CA2014304A1 - Monoclonal antibody to novel anitgen associated with human tumors - Google Patents

Abstract

ABSTRACT

The present invention is concerned with a novel monoclonal antibody which binds strongly to a protein antigen associated with human tumors, including carcinomas of the colon and lung. The antibody binds to normal human cells to a much lesser degree than to tumor cells. The antibody finds use both in diagnostic methods such as the detection of malignant cells associated with tumors and in therapeutic methods for treatment of humans with tumors. Also disclosed is a novel 66,000 dalton glycoprotein antigen found on the cell surface of human tumor cells. The amino terminal amino acid sequence of this antigen is:

Description

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NOVEL MONOCLONAL ANTI~ODY TO NOVEL A~TIGEN
ASSOCIATED WITH HUM~N TUMORS

Fleld of the Invention The present invention relates to a novel monoclonal antibody and a novel antigen, and to methods for production and use of such novel monoclonal antibody reactive with human carcinoma cells. More specifically, the monoclonal antibody of this invention is reactive with the novel cell surface antigen which is associated with a variety of human tumors including carcinomas of the colon and lung.

The monoclonal antibody of this invention is suitable for both ln vivo and ln vitro clinical diagnostic purposes, such as the detection of malignant carcinomas. Additionally the antibody of the present invention is suited for therapeutic uses, for example to react with tumor cells, and in conjugates as a target-selective carrier of various agents which have anti-tumor effects including, but not limited to: chemotherapeutic drugs, toxins, immunological response modifiers, and radioisotopes. The antigen of the invention is also useful for therapeutic and diagnostic purposes.

Background of the Invention Carcinomas cause millions of deaths annually.
For example, lung carcinomas are responsible for the majority of deaths from cancer among men and are overtaking breast carcinomas as the most frequent cause of cancer death among women. Most cases of carcinomas are incurable by chemotherapy and radiation therapy unless radically removed in the early stages of the disease. There is thus a great need for methods of diagnosis and therapy of carcinomas of the breast, colon, ~ c3 ovary and lung, as well as for o~her malignank neoplasms such as melanomas and sarcomas.

Monoclonal antibodies reactive with carcinoma-associated antigens are known (see, e.g., Papsidero, Semin. Surq. Oncol., 1 (4):171-81 (1985); Schlom et al., Important Adv. Oncol., 170-92 (1985); ~llum et al., Surg.
Ann., 18:41-64 (1986); Houghton et al., Semin Oncol., 13 (2):165-79 (1986); Monoclonal Antibodies in Cancer:
Advances for Diaqnosis and Treatment, Roth (ed.), Futura Publishing, Mt. Kisco, New York (1986); and Cancer Diaqnosis In Vitro Using Monoclonal Antibodies, Kupchik (ed.) Marcel Dekker, Inc., New York, (1988)).

Most of the known monoclonal antibodies are reactive with several types of human carcinomas, while a few antibodies react with carcinomas derived from specific organs of the body, e.g., lung, breast, ovary, colon, stomach or pancreas. The target antigens are commonly glycoproteins or glycolipids (see, e.g., Hellstrom et al., Cancer Research, 46:3917-23 (19~6); and Fink et al., Proq. Clin. Pathol., 9:121-33 (1984)). For example, monoclonal antibodies reactive with glycoprotein antigens on specific types of carcinomas include those described in United States Patent 4,737,579 (monoclonal antibodies to non-small cell lung carcinomas); United States Patent 4,753,894 (monoclonal antibodies to human breast cancer); United States Patent 4,579,827 (monoclonal antibodies to human gastrointestinal cancer);
and United States Patent 4,713,~52 (monoclonal antibodies to human xenal carcinoma). Some monoclonal antibodies react with high molecular weight antigens which appear to be mucins. For example, monoclonal antibody B72.3 appears to recognize a tumor-associated oncofetal glycoprotein antigen of greater than 1,000 kd molecular weight that is selectively expressed on a number of different carcinomas. Thus, B72.3 has been shown to react with 84% of breast carcinomas, 94% of colon carcinomas, 100% of ovarian carcinomas and 96% of non-small-cell lung carcinomas (see Johnston, Acta CYtol., 1 (5):537-56 (1987) and United States Patent 4,612,282, issued to Schlom et al.). Similarly, monoclonal antibody KC-~ recognizes an approximately 400-~00 kd protein antigen expressed on a number ofcarcinomas, such as colon, prostate, lung and breast carcinoma (See United States Patent 4,708,930).

Monoclonal antibodies reactive with glycolipid antigens that are believed to be associated with certain tumor cells have also been disclosed. For example, Young et al., J. Exp. Med., 150:1008-19 (1979) disclose the production of two monoclonal antibodies specific for asialo GM2, a cell surface glycosphingolipid antigen that was established as a marker for BALB/c 3T3 cells trans~ormed by Kirsten murine sarcoma virus. See, also, Kniep et al., J. Immunol., 131 (3):1591-94 (1983) and United States Patent 4,507,391 (monoclonal antibody to human melanoma).

In addition, monoclonal antibodies reactive with glycolipid antigens found on specific types of carcinoma cells include those described by Rosen et al., Cancer Research, 44:2052-61 (1984) (monoclonal antibodies to human small cell lung cancer); Varki et al., Cancer Research, 4~:681-87 (1984) (monoclonal antibodies to human adenocarcinomas of the lung, stomach and colon and melanoma); and United States Patent 4,579,827 (monoclonal antibodies to human colon adenocarcinoma). See, also, Hellstrom et al., Proc. Nat'l. Acad. Sci. USA, 83:7059-63 tl986) which describes the L6 monoclonal antibody that recognizes a carbohydrate antigen expressed on the surface of human non-small cell lung carcinomas, breast carcinomas and colon carcinomas.

Additional monoclonal antibodies exhibiting a reactivity to antigens found on a variety of tumor cells are greatly needed. This is because oE the antigenic heterogeneity of most tumors which often necessitates, in ~ J ~

diagnosis or therapy, the use of a combination of different monoclonal antibodies directed to the same tumor mass. Furthermore, monoclonal antibodies that display a high degree of reactivity with a wi~e range of tumors, while showing the absence of or only a very weak reactivity with normal tissues, are not common. Such antibodies would clearly be advantageous.

It is thus apparent that a monoclonal antibody reactive with an antigen expressed at high levels by a variety of tumors may become useful towards an earlier diagnosis of cancers, a better definition of the spread of the cancer, the immunological monitoring of cancer patients, as well as for development of improved methods for therapy of cancers. It is also apparent that monoclonal antibodies to novel cell surface molecules can be used for further definition of such molecules which may be of value for preparing immunogens in the form of cancer vaccines, and which may also have important cellular functions, for example, as receptors of hormones or growth factors or as molecules otherwise involved in intra- and intercellular communication. The antigens may even have enzymatic or growth factor activity by themselves.

Summary of the Invention The present invention provides such a monoclonal antibody, C1, which is specific for a determinant site on a cell surface glycoprotein antigen, the Cl antigen, associated with human tumor cells, particularly cells from lung and colon carcinomas. Thus, the antibody of the invention can be useful for the diagnosis and therapy of tumors expressing the C1 antigen identified by antibody C1. The C1 antibody of the invention is of the class IgG, and IgGl subclass, and it shows no significant reactivity with normal human cells.

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The antibody of the invention may be used in 1n vltro diagnostic methods for determining the presence of a malignant condition in human lung tissue and other human tissues. The methods involve examining the tissue for the presence of an antigen having the characteristics of the 66,000 dalton Cl antigen glycoprotein reactive with antibody Cl. For example, the tissue can be contacted with the C1 monoclonal antibody of the invention which defines a determinant site on a cell-associated antigen having the characteristics of the C1antigen, a functional e~uivalent or a fragment of this antibody and any interactions of said antlbody and antigenic determinants are detected. One such method involves the determination of the presence of carcinoma cells in a specimen suspected of containing such cells.
The specimen is contacted with the monoclonal antibody, which is capable of distinguishing such cells from other cell types which may be present in the specimen. The contact is carried out under conditions for binding of the antibody to such cells. After contact, the presence or absence of binding of the antibody to the cells in the specimen is determined. This bindiny is related to the presence or absence of carcinoma cells in the specimen.
Generally, the specimen is contacted with a labeled specific binding partner of the monoclonal antibody.
This label is capable of producing a detectable signal.
Alternatively, the monoclonal antibody itself may be labeled.

Another diagnostic method involves the in vivo localization of a tumor by administering to a patient a purified antibody or antibody fragment of the present invention labeled with an agent which gives a detectable signal. The localization is then detected using external scintigraphy, emission tomography or radionuclear scanning. This method can also provide better ways to stage cancer patients with respect to the extent of disease and to monitor changes in response to therapy.

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The invention also has therapeutic applications, since the C1 antihody and similar antibodies can react with the C1 antigen that is expressed in high concentrations at the tumor cell surface. The monoclonal antibody of the invention may be used to prepare a composition for treating tumors. The composition comprises a therapeutically effective amount of the antibody in association with a pharmaceutically - acceptable parenteral vehicle. The antibody of the invention can also be used in immunoconjugates as a carrier of various agents which have an antitumor effect, including, but not restricted to, chemotherapeutic drugs, toxins, immunological response modifiers, and radioisotopes.
The invention also comprises the novel C1 antigen characterized by a molecular weight of about 66,000 daltons and having an amino terminal amino acid sequence:

X-E-L-T-I-L-H-T-N-D-V-H-S-~-L-E-~-T-S-X

in which X represents an unidentified amino acid, and equivalents, identified by antibody C1 and the class of antibodies that bind to this antigen.

The invention includes methods for using the ~5 purified or cloned C1 antigen as a vaccine to immunize against certain tumors Detailed Desc~ption of Invention In order that the invention herein described may be more fully understood, the following detailed description is set forth.

The present invention concerns a novel monoclonal antibody, designated C1, which is specifically reactive with an antigen (Cl antigen) localized on human s3 f~

tumor cells, particularly from carcinomas of the lung and colon, methods for producing the Cl monoclonal antibody and diagnostic and therapeutic methods employing the antibody. The C1 antibody reacts with a range of tumors while sho~ing essentially no reactivity with normal human tissues or other types of tumors such as melanomas or lymphomas.

The invention further concerns a novel cell surface glycoprotein antigen, designated C1 antigen, and primarily associated with human tumors of the lung and colon, and methods for using the C1 antigen.

The monoclonal ant.body of the invention can be prepared by hybridoma fusion techniques or by techniques that utilize EBV-immortalization technologies.

Hybridoma fusion techniques were first introduced by Kohler and Milstein (see, Kohler and Milstein, Nature, 256:495 97 (1975); Brown et al., J. Immunol., 127 (2):539~46 (1981); Brown et al., J. Biol. Chem., 255:4980-83 (1980); Yeh et al., Proc.
Nat'l. Acad. Sci. (USA), 76 (6):2927-31 (1976); and Yeh et al., Int. J._ Cancer, 29:269-75 (1982)).

These techniques involve the injection of an immunogen (e.g., purified antigen or cells or cellular extracts carrying the antigen) into an animal (e.g., a mouse) so as to elicit a desired immune response (i.e., production of antibodies) in that animal. For example, human lung carcinoma cells from pleural effusions, cultured cells from explanted human non-small cell lung carcinomas (NSCLC), or cells from a normal fetal lung or lysates from such cells may be used as the immunogen. In Example I, infra, a membrane preparation from human adenocarcinoma of the colon designated H3059 and cells from the colon carcinoma cell line 3347 are used as the immunogen. The membrane preparation is injected, for example, into a mouse, and after a sufficient time the mouse is sacrificed and somatic antibody-producing lymphocytes are obtained. Antibody-produciny cells may be derived from the lymph nodes, spleens and peripheral blood of primed animals. Spleen cells are preferred.
Mouse lymphocytes give a higher percentage of stable fusions with the mouse myelomas described below. The use of rat, rabbit and frog somatic cells is also possible.
The spleen cell chromosomes encoding desired immunoglobulins are immortalized by fusing the spleen cells with myeloma cells, generally in the presence of a fusing agent such as polyethylene glycol (PEG). Any of a number of myeloma cell lines may be used as a fusion partner according to standard techniques; for example,~
the P3-NS1/1-Ag4-1, P3-x63-Ag~.653 or Sp2/O-Agl4 myeloma lines. These myeloma lines are available from the American Type Culture Collection (ATCC), Rockville, Maryland.

The resulting cells, which include the desired hybridomas, are then grown in a selecti~e medium, such as HAT medium, in which unfused parental myeloma or lymphocyte cells eventually die. Only the hybridoma cells survive and can be grown under limiting dilution conditions to obtain isolated clones. The supernatants of the hybridomas are screened for the presence of antibody of the desired specificity, e.g., by immunoassay techniques using the antigen that has been used for immunization. Positive clones can then be subcloned under limiting dilution conditions, and the monoclonal antibody produced can be isolated. Various conventional methods exist for isolation and purification of the monoclonal antibodies so as to free them from other proteins and other contaminants. Commonly used methods for purifying monoclonal antibodies include ammonium sulfate precipitation, lon exchange chromatography, and affinity chromatography (see, e.g., Zola et al., in Monoclonal Hybridoma Antibodies: Techniques and Applications, Hurell (ed.) pp. 51-52 (CRC Press 1932))~
Hybridomas produced according to these methods can be 2a,~.f,l;3i~3,~.ol propagated in vitro or ln vivo (in ascites fluid) using techniques known in the art (See, generally, Fink et al., supra, at page 123, Fig. 6~1).

Generally, the individual cell line may be propagated ln vitro, for example in laboratory culture vessels, and the culture medium containing high concentrations of a single specific monoclonal antibody can be harvested by decantation, ~iltration or centrifugation. Alternatively, the yield of monoclonal antibody can be enhanced by injecting a sample of the hybridoma into a histocompatible animal of the type used to provide the somatic and myeloma cells for the original fusion. Tumors secreting the specific monoclonal antibody produced by the fused cell hybrid develop in the injected animal. The body fluids of the animal, such as ascites fluid or serum, provide monoclonal antibodies in high concentrations. ~s discussed by Cole et al., su~ra, when human hybridomas or EBV-hybridomas are used, it is necessary to avoid rejection of the xenograft injected into animals such as mice. Immunodeficient or nude mice may be used or the hybridoma may be passaged first into irradiated nude mice as a solid subcutaneous tumor, cultured ln vitro and then injected intraperitoneally into pristane primed, irradiated nude mice which develop ascites tumors secreting large amounts of specific human monoclonal antibodies (See Cole et al., supra).

For certain therapeutic applications chimeric (mouse-human) or human monoclonal antibodies may be preferable to murine antibodies because patiants treated with mouse antibodies generate human antimouse antibodies. (Shawler et al., J. Immunol., 135:1530-35 (1985)). Chimeric mouse-human monoclonal antibodies reactive with the C1 antigen can be produced, for example, by techniques recently developed for the production of chimeric antibodies (oi et al., Biotechnoloqies, 4(3):214-221 (19~6); Liu et al., Proc.
Nat'l. Acad. Sci. (USA), 84:3439-43 (1987)).

~ b,S ~ ~, 9 Accordingly, genes coding for the constant regions of the murine C1 antibody molecule are substituted with human genes coding for the constant regions of an antibody with appropriate biological activity (such as the ability to activate human complement and mediate ADCC). Novel antibodies of mouse or human origin, can also be made to the C1 antigen having the appropriate biological functions. For example, human monoclonal antibodies may be made by using the antigen, e.g., the C1 antigen of the invention, to sensitize human lymphocytes to the antigen in vitro followed by EBV-transformation or hybridization of the antigen-sensitized lymphocytes with mouse or human lymphocytes as described by Borrebaeck et al. (Proc.
Nat'l. Acad. Sci~ (USA), ~5:3995-99 (1988)).

According to a preferred embodiment, the antibody of this invention, designated C1, was produced via hybridoma techniques using membranes from colon adenocarcinoma effusion cells and cells from a colon carcinoma cell line 3347 as the immunogen as described in Example I, infra. The C1 hybridoma, producing the C1 ankibody, has been deposited with the ATCC, Rockville, Maryland, and has there been identi~ied as follows:

C1 Accession No.: HB 9803 The C1 antibody is of the IgG1 subclass. The antibody displays a very strong reactivity with tumor cells, particularly cells from colon and lung carcinomas.
The Cl antibody shows no detectable binding to the lymphoma cell lines, CEM, MOLT-4, the B cell lymphoma line P3HR-1, and to melanoma cells.

In addition, the antibody of this invention does not display any immunohistologically detectable binding to normal human tissues such as fibroblasts, endothelial cells or epithelial cells from the major organs, e.g., kidney, spleen, liver, skin, lung, breast, colon, brain, thyroid, heart, lymph nodes or ovary. Nor t ,~ s~3 (~

does the antibody react with peripheral blood leukocytes.
Thus, this antibody is superior to most known antitumor antibodies in its specificity for a range of tumor cells and in its high degree of specificity for tumor cells as compared to normal cells (See, e.g., Hellstrom et al., Covalently Modified Antiqens And Antibodies In Diaanosis And Therapy, Quash/Rodwell (eds.), pp. 24-28 (Marcel Dekker, Inc. (1989); and Bagshawe, Br. J. Cancer, 48:167-75 (1983)).

It should be understood that the present invention encompasses the C1 antibody described above and any fragments thereof containing the active binding region of the antibody, such as Fab, F(ab)2 and Fv fragments. Such fragments can be produced from the C1 antibody using techniques well established in the art (see, e.g., Rousseaux et al., in Methods Enzymol., 121:663-69, Academic Press (1986)).

In addition, the present invention encompasses antibodies that are capable of binding to the same antigenic determinant as the Cl antibody and competing with the Cl antibody for binding at that site. These include antibodies having the same antigenic specificity as the Cl antibody but differing in species origin, isotype, binding affinity or biological functions (e.g., cytotoxicity). For example, class, isotype and other variants of the antibody of the invention may be constructed using recombinant class-switching and fusion techniques known in the art (see, e.g., Thammana et al., Eur. J. Immunol., 13.614 (1983); Spira et al., J. Immunol. Meth., 74:307-15 (1984); Neuberger et al., Nature, 312:604-08 (1984); and Oi et al., supra)). Thus, chimeric antibodies or other recombi.nant antibodies (e.g., antibody fused to a second protein such as a lymphokine) having the same binding specificity as the C1 antibody fall within the scope of this invention.
Furthermore, since the C1 antigen to which the antibody of the invention binds is a novel tumor antigen, the ~ ,_, ,7, ~ J l~

antibody of the invention includes antibodies thak bind to any antigenic determinant on that Cl antigen, including determinants other than that with which the Cl antibody reacts.

Also included within the scope of the invention are anti-idiotypic antibodies of the Cl antibody of the invention. These anti-idiotypic antibodies can be produced using the Cl antibody as immuno~en and are useful for diagnostic purposes in detecting humoral response to tumors and in therapeutic applications, e.g., in a vaccine, to induce an anti-tumor response in patients (See, e.g., Nepom et al., Cancer_And Metastasis Reviews, 6:487-501 (1987); and Lee et al., Proc. Nat'l.
Acad. Sci. (USA!, 82:6286-90 (1985)).

The Cl antibody can be used to isolate and characterize the Cl antigen to which it binds. Thus, Cl can be used as a probe to identify and characterize the epitope recognized by the antibody and to further define the Cl antigen on the surface of the carcinoma cells 20 (see, e.g., Hakomori, Ann. Rev. Immunol., 2:103-26 (1984); Brown et al., J. Immunol., 127: 539-546 (1981); Brown et al., Nature, 296: 171-173 (1982); and Rose et al.; Proc. Nat'l. Acad.
Sci. (USA~, 83: 1261-1265 (1986)).

The Cl antigen recognized by the monoclonal antibodies of the present invention comprises a novel cell surface glycoprotein antigen characteristic of tumor cells, particularly cells from carcinomas of the colon and lung. ~1 antigen has a molecular weight of about 30 66,000 daltons when subjected to immunoprecipitation on polyacrylamide gel electrophoresis.

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The amino terminal amino acid sequence of the novel Cl glycoprotein antigen is as follows:

X-E-L-T-I-L-H-T-N-D-V-H-S-R-L-E-~-T-S-X

in which X represents an amino acid that has not been identified as yet, and the rest of the letters represent the conventional single letter abbreviations for amino acids. A comparison of the 20 residue C1 amino-terminal sequence with those stored in the current protein data base (PI~
Release 16, March 1988; Gen BANK Release 57.0, September 1988; NEW, November 30, 1g88; DIF, November 30, ls88;
SWISSPROT, November 30, 1988; LOSPRO, November 30, 1988) reveals no significant sequence homology with any other known sequences.

The monoclonal antibody of the invention is also useful for diagnostic applications, both in vitro and in vivo, for the detection of human carcinomas carrying the C1 antigen with which the Cl antibody is specifically reactive. In vitro diagnostic methods are well ~nown in the art (See, e.g., Roth, supra and Kupchik, supra) and include immunohistological detection of tumor cells (e.g., on human tissue, cells or excised tumor specimens) or serologic detection of tumor-associated antigens (e.g., in blood samples or otherbiological fluids).
Immunohistological techniques involve contacting a biological specimen such as a tumor tissue specimen with the antibody of the invention and then detecting the presence on the specimen of the antibody complexed to its antigen. The formation of such antibody-antigen complexes with the specimen indicates the presence of tumor cells in the tissue. Detection of the antibody on the specimen can be accomplished using techniques known in the art, such as the immunoperoxidase staining technique, the avidin-biotin (ABC) ~echnique or ~ ~ A ,~3 ~ !~
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immunofluorescence techniques (see, e.g., Ciocca et al., Meth. Enzymol., 121:562-79 (1986); Hellstrom et al., Cancer Research, 46:3917-23 (1986); and Kimball (ed.), Introduction To Immunoloqy (2nd Ed.), pp. 113-117, Macmillan Publ. Co. (1986)). For example, immunoperoxidase staining was used as described in Example III, infra, to demonstrate the reactivlty of the Cl antibody with lung and colon carcinomas, and the lack of reactivity of the antibody with normal human tissue specimens.

Serologic diagnostic techniques involve the detection and quantitation of tumor-associated antigens that have been secreted or "shed" into the serum or other biological fluids of patients thought to be suffering from carcinoma. Such antigens can be detected in the body fluids using techniques known in the art such as radioimmunoassays (RIA) or enzyme-linked immunosorbent assays (ELISA) wherein an antibody reactive with the "shed~' antigen is used to detect the presence of the antigen in a fluid sample (see, e.g., Uotila et al., J.
Immunol. Methods, 42:11 (1981) and Allum et al., supra at pp. 48-51). These assays, using the C1 antibody disclosed herein, therefore can be used for the detection in biological fluids of the Cl antigen with which the Cl antibody reacts and thus the detection of various carcinomas in human patients. Thus, it is apparent from the foregoing that the Cl antibody of the invention can be used in most assays involving antigen-antibody reactions. These assays include, but are not limited to, standard RIA techniques, both liquid and solid phase, as well as ELISA assays, immunofluorescence techniques, and other immunocytochemical assays (see, e.g., Sikora et al.
(eds.), Monoclonal Antibodies, pp. 32 52, Blackwell Scientific Publications, (198~)).

The Cl antibody of the invention is also useful for in vivo diagnostic applications for the detection of human tumors. One such approach involves the detection , C3 of tumors ln vlvo by tumor imaging techniques using the antibody labeled with an appropriate imaging reagent that produces detectable signal. Imaging reagents and procedures for labeling antibodies with such reagents are well known (see, e.g., Wensel and Meares, Radio Immunoimaqinq and Radioimmunotherapy, Esevier, New York (1983); Colcher et al., Meth. Enzymol., 121:802-16 (1986)). The labeled antibody may be ~etected by a technique such as radionuclear scanning (see, e.g., Bradwell et al. in Monoclonal Antibodies for Cancer Detection and Therapy, Baldwin et al. (eds.), pp. 65-85, Academic Press (1985)).

The C1 antibody of the invention has a number of ln vivo therapeutic a~pIications. In addition to being used alone to target tumor cells, the antibody can be used in conjunction with an appropriate therapeutic agent to treat human cancer. For example, the antibody can be conjugated or linked to a therapeutic drug or toxin for delivery of the therapeutic agent to the site o~ the cancer. Techniques for conjugating such therapeutic agents to antibodies are well known (see, e.g., Arnon et al., Monoclonal Antibodies And Cancer Therapy, Reisfeld et al. (eds.), pp. 2~3-56, AIan R.
Liss, Inc., (1985~; Hellstrom et al. in Controlled Drug Delivery (2nd ed.), Robinson et al. (eds.~, pp. 623-53, Marcel Dekker, Inc., (1987); Thorpe, Monoclonal Antibodies '8~. Biological And Clinical Applications, Pinchera et al. (eds.), pp. 475~506 (1985~; and Thorpe et al., Immunol. Rev., 62:119-58 (1982)). Since the C1 antibody is not easily internalized when cells are exposed to it ln vitro, it may be preferable to target chemotherapeutic drugs to the tumor cells by coupling the antibody with an enzyme, e.y., usiny direct chemical coupling or recombinant DNA techniques. When such conjugates are localized to the tumor, the enzyme can convert an inactive (nontoxic) prodrug, which is administered after the conjugates have bound to the tumor cells, to an active anticancer drug. (See, e.g., Senter ~ ~ ,),, ,,L~ S

et al., Proc._Nat'l. Acad Sci. (USA), 85:48~2-46 (1988)).

Alternatively, the antibody can be coupled to a source o~ high-energy radiation, e.g., a radioisotope such as 131I, which, when localized at the tumor site, results in a killiny of several cell diameters (See, e.g., Order, in Monoclonal Antibodies For Cancer Detectlon And Therapy, ~aldwin et al. (eds.), pp. 303-16, Academic Press, (1985)). According to yet another embodiment, the C1 antibody can be conjugated to a second antibody to form an antibody heteroconjugate for the treatment of tumor cells as described by Segal in United States Patent 4,676,9~0.

Still other therapeutic applications for the C1 antibody of the invention include its use, either in the presence of complement or as part of an antibody-drug or antibody-toxin conjugate, to remove tumor cells from the bone marrow of cancer patients. According to this approach, autologous bone marrow may be purged ex vlvo by treatment with the antibody and the marrow infused back into the patient (See, e.g., Ramsay et al., J. Clin.
Immunol., 8~2):81-88 (1988)).

Furthermore, chimeric or other recombinant C1 antibodies of the invention, as described earlier, may be used therapeutically. For example, a fusion protein comprising at least the antigen-binding region of the C1 antibody joined to at least a functionally active portion of a second protein having anti-tumor activity, e.g., a lymphokine or oncostatin, may be used to treat human tumors ln vivo. In addition, a chimeric C1 antibody wherein the antigen-binding reyion of C1 is ~oined to a human Fc region, e.g., IgG1, may be used to promote - anti~ody-dependent cellular cytotoxicity or complement mediated cytotoxicity. Furthermore, recombinant techniques known in the art can be used to construct ~ J,7 bispecific antibodies wherein one of the binding specificities of the antibody is that of the C1 antibody (See, e.g., United States Patent 4,474,893).

S Finally, anti-idiotypic antibodies of the C1 antibody may be used therapeutically in active tumor immunization and tumor therapy (See, e.g., Hellstrom et al., "Immunological Approaches To Tumor Therapy Monoclonal Antibodies, Tumor Vaccines, And Anti-Idiotypes" in Covalently Modified Antiqens and Antibodies In Diaqnosis and Therapy, supra, at pp. 35-41)-It is apparent, therefore, that the presentinvention encompasses pharmaceutical compositions, combinations and methods for treating human tumors. For example, the invention includes pharmaceutical compositions for use in the treatment of human tumors comprising a pharmaceutically effective amount of a C1 antibody and a pharmaceutically acceptable carrier. The compositions may contain the C1 antibody, either unmodified, conjugated to a therapeutic agent (e.g., drug, toxin, enzyme or second antibody) or in a recombinant form (e.g., chimeric or bispecific C1). The compositions may additionally include other antibodies or conjugates for treating carcinomas (e.g., an antibody cocktail).

The antibody compositions of the invention can be administered using conventional modes of administration, including, but not limited to, intravenous, intraperitoneal, oral, intralymphatic or administration directly into the tumor. Intravenous administration is preferred.

The antibody compositions of the invention may be in a variety of dosage ~orms which include, but are not limited to, li~uid solutions or suspensions, tablets, pills, powders, suppositories, polymeric microcapsules or microvesicles, liposomes, and injectable or infusible solutions. The preferred form depends upon the mode of administration and the therapeutic application.

The antibody compositions also pre~erably include conventional pharmaceutically accepka~le carriers and adjuvants known in the art such as human serum albumin, ion exchangers, alumina, lecithin, buffer substances such as phosphates, glycine, sorbic acid, potassium sorbate, and salts or electrolytes such as protamine sulfate.

The most effective mode of administration and dosage regimen for the compositions of this invention depends upon the severity and course of the disease, the patient's health and response to treatment, and the judgment of the treating physician. Accordingly, the dosages of the compositions should be titrated to the individual patient. Nevertheless, an effective dose of the antibody compositions of this invention may be in the range of from about l to about 5000 mg/m2.

The novel antigen of the present invention, referred to as antigen Cl may also be used for therapeutic applications. The antigen can be purified from tumors or produced by recombinant DNA technology (Brown et al., copending U.S. Patent Application Serial No. 827,313, Attorney Docket No. 5624-008, filed on February 7, 1986, incorporated by reference herein). The gene coding for the C1 antigen may be cloned by methods which first enrich the mR~TA of the Cl antigen. By one such method, polysomes (consisting of mR~TA ribosomes and nascent polypeptide chains) can be purified by immunoaf~inity chromatography with antibody that recognizes the Cl antigenic determinant on the nascent chain. The mRNA is isolated by immunoprecipitation with, e.g., C1 antibody and the cDNA is cloned in an appropriate expression vector.

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Alternatively, Cl antibody or antiserum to Cl antigen might be used to screen a cDNA library usin~ an expression vector. The purified or cloned Cl antigen may be administered alone as an immunogen or together with a proper immunological adjuvant.

Purified or cloned C1 antigen may be used in the methods of the invention as a vaccine to immunize against certain tumors. Procedures for preparing such vaccines are known in the art (see, e.g., Estin et al., Proc~ Nat'l. Acad. Sci. (USA), 85:1052 (1988)). Briefly, recombinant viruses are constructed for expression of the cloned tumor-associated antigen, for example, Cl antigen.
Cells infected with the recombinant viruses will express the tumor antigen at the surface of the cells together with the host's incompatibility antigens and immunogenic viral proteins. This favors the induction of cellular immunity which plays a key role in tumor rejection. A
suitable virus, for example, vaccinia virus derived from a plaque-purified virus of the Wyeth smallpox vaccine (New York City Board of Health strain), is used to construct a recombinant virus containing the coding sequence of the Cl antigen under control of the vaccinia virus "7.5 K" promoter (Hu et al., J. Virol., 62:176-180 (1988)). The recombinant virus may then be administered intravenously as a vaccine to protect against cancer.

In order that the invention described herein may be more fully understood, the follo~ing examples are set forth. It should be understood that these examples are for illustrative purposes only and are not to be construed as limiting the scope of this invention in any manner.

EXAMPLE I

Preparation of the C1 Monoclonal Antibody The Cl monoclonal antibody of the invention was produced using hybridoma fusion techniques described previously by Yeh et al., Proc. Nat'l Acad. Sci. (USA) (1979), supra. All cell lines used in the following examples were developed at Oncogen, Sea~tle, Washington, from samples of tumors obtained from humans either as solid tumors or effusions. Briefly, a three month-old BALB/c mouse was immunized four times using a membrane preparation of a human adenocarcinoma of the colon, designated H3059, and three times using cells from colon carcinoma cell line 3347. The membrane preparation was prepared as follows: Tumor was obtained from ascites 15 effusion. 10 mls of lysing buffer (19.8 ml deionized water and 0.1 ml of 0.2 M NaHC03 and 0.1 m~ of 0.2 M PMSF
tprotease inhibitor) in ethanol) was added to the cells and disrupted on ice 25 to 50 times. The mixture was then transferred to a 15 ml tube, and spun for 2 min. at 20 2000 X G at 0C. The supernatant was removed and transferred to a 5 ml cellulose tu~e. The pellet was checked under a microscope for lysis. The supernatant was then centrifuged on an ultra-centrifuge for 15 min.
at 37,000 X G at 4C. The supernatant was then aspirated and the pellet resuspended in at least 1 ml of PBS. The suspension was transferred to a 5 ml tube and sonicated on ice for 1 min. A 1:100 dilution was made and the protein concentration was determined using the Bradford procedure (Bradford, Analytic Biochemistry, 72:248-254 (1976)). The membrane preparations were stored frozen in aliquots of 0.2 ml in a Revco freezer (-70C.).
The mouse received seven (7) injections (inj.) as follows:

1st inj.: 100 ~g membrane preparation + 100 ~g muramyl dipeptide (MDP)/50 ~1 + 50 ~1 2 r, incomplete ~reund1s adjuvant given subcutaneously (s.c.) at 4 sites;
2nd inj.: 100 ~g membrane preparation given s~c.
at 4 sites;
3rd inj.: 100 ~g membranes given intraperitoneally ~i.p.);
4th inj.: 100 ~g membranes given i.p. and s.c. at 4 sites;
5th inj.: 107 3347 cells given i.p. and s.c. at 4 sites;
6th inj.: 107 3347 cells given i.p. and s.c. at 4 s ites;
7th inj.: 106 3347 cells given i.p. and s.c. at 4 sites;

Three days after the last immunization, the spleen was removed, and the spleen cells were suspended - in culture medium. The spleen cells were then fused with ATCC CRL 1580, P3 X 63 ~ Ag8.653 cells, using polyethylene glycol (PEG), and the cell suspension grown in microliter wells in selective HAT medium as described by Yeh et al., Proc. Nat'l. Acad. Sci. (USA), supra. The mixture was seeded to form low density cultures originating from single fused cells or clones.

Bindin~ Assays The supernatants from these hybridoma cultures were then screened for direct binding activity on the colon cancer cell line 3347~ using an ELISA assay similar to that described by Douillard et al., Meth. Enzymol., 92 168-74 (1983)o According to this assay, the antigen (with which the antibody being screened for is reactive) is immobilized on microtiter plates and then incubated with hybridoma supernatants. If a supernatant contains the desired antibody, the antibody will bind to the immobilized antigen and is detected by addition of an anti-immunoglobulin antibody-~nzyme conjugate and a ~ .J 3~

substrate for the enzyme which leads to a measurable change in optical density.

~ or this example, colon cancer cells were dispensed into a 96-well tissue culture plate (Costar, Cambridge, MA) and incubated overnight in a humid 37C
incubator (5~ Co2). The cells were then fixed with 100 ~l of freshly prepared 1.0% glutaraldehyde to a final well concentration of 0.5% and incubated for 15 min. at room temperature, followed by washing three times with 1 X
PBS. The cells were next blocked for 1 hr. with 5% BSA
in PBS and washed again three times with PBS. The supernatants from the hybridoma cultures were then added at 100 ~l/well, the wells incubated for 1 hr. at room temperature, and the cells washed three times with PBS.
Next, goat anti-mouse horseradish peroxidase (Zymed, CA) diluted in 0.1% BSA and PBS was added to a concentration of 100 ~l/well. The reaction mixture was incubated for either 1 hr. at room temperature or 30 min at 37C and the cells were then washed three times with PBS. o phenylenediamine (OPD) was then added at 100 ~1/well and the plates incubated in the dark at room temperature for 5-45 min. Antibody binding to the cells was detected by a color change in the wells that occurred within 10-20 min. The reaction was stopped by adding 100 ~1/well H2S04 and the absorbance read in a Dynatech (Alexandria, VA) Microelisa autoreader at 492 nm.
Next the antibody was tested in a fluorescent assay using 3347 cells attached to coverslips and stained with fluorescein. Cultured 3347 cells were plated in 24 well tissue culture plates with sterile glass coverslips at a density of 1 to 2 x 105 cells per well and allowed to grow to 75-90% confluency. The cells were fixed with 3%
paraformaldehyde for five minutes and then washed with binding buffer. 250 ~l of antibody containing supernatant diluted 1:2 with binding buffer was added to each well and incubated for 30 min. at room temperature or at 37C. The cells were then washed three times.

Then 250 ~1 of an optimal dilution of FITC conjuyated goat anti-mouse IgG antibody ~TAG0, Burlin~ame, CA) was added to each well and incubated as before. The wash step was then repeated and the coverslips removed and mounted on microscope slides. Staining patterns were read using a ~luorescence microscope.

Supernatants from wells positive on the colon carcinoma cell line in both the ELISA and fluorescence assays were further tested by immunohistology technology on 3347 cell pellets, colon carcinoma tissue and normal kidney, liver, and spleen tissues as described in Example II, infra.

It should be noted that the ELISA assay can be performed using intact cells or purified soluble antigen or cellular extracts as the immobilized antigen. When soluble antigen or cell extracts were used as antigen, the antigen was initially plated at 50 ~l/well in PBS and the plates were incubated overnight at room temperature before beginning the assay. When using intact cells as antigen, they may be used fresh or after fixation. In either case, the cells were initially plated at 104 cells at 100 ~l/well in culture medium and incubated overnight or until confluency in a 37C incubator (5~ C02).

Hybridomas which produced antibodies binding to the colon cancer cell line and not to the normal tissues were thus selected, cloned, e~panded ln vitro, and further tested for antibody specificity. Those hybridomas which produced antibody reactive with human colon cancer were recloned, expanded, and injected into pristane-primed 3-month old BALB/c mice, where they grew as ascites tumors.

Following this procedure, hybridoma cell line Cl was obtained, cloned and injected into mice to develop as an ascites tumor. As disclosed above, the Cl hybridoma has been deposited with the ATCC. Antibody 2 ; L ~.3 ~

secreted into the ascites was purified on protein A~ or protein G-Sepharose (see, e~g., Ey et al., Immunochemistry, 15:429-436 (1978)) or by gel filtration on Sephacryl S-300. Purified C1 antibody was used for further characterization.

EXAMPLE II

Characterization of The Cl Monoclonal Antibody Isotype Determination To determine the class of immunoglobulin produced by the Cl hybridoma, the following techniques were utilized:

a) Ouchterlony immunodiffusion.

An aliquot of supernatant of the C1 hybridoma cells was placed into the center well of a 25% agar plate. Monospecific rabbit anti-mouse Ig isotypes antibodies (Southern Biotechnology, Birmingham, AL) were placed in the outer wells, and the plate was incubated for 2~-48 hr. at 37C. Precipitation lines were then read.

b) ELISA isotyping.

Dynatech Immulon 96-well plates were coated with goat anti-mouse Ig antibodies at 1 ~g/ml concentration, 50 ~l/well in PBS and left covered overnight at 4C. The plates were washed with PBS/Tween 20, 0.05%. After washing the plates, supernatants from the Cl hybridoma were added and incubated at room temperature for 1 hr. After washing wikh PBS/Tween 20 containing bovine serum albumin (BSA), plates were incubated at 37C for 2 hr. with monospecific goat anti-mouse Ig-HRP isotype antibodies coupled to peroxidase (Zymed). After washing, plates were incubated with 1 mg/ml o-phenylenediamine and 0-03% H22 in 0.1 ~ citrate buffer, pH 4. 5 . Optical density at 490 and 630 nm was determined on a Dynatec ELISA plate reader.

Based on these procedures, it was determined that the Cl monoclonal antibody is of the IgG1 isotype.

Bindinq Characteristics of The c1 Monoclonal Antibody The subcellular localization of antigen was determined by measuring antibody binding to cells before or after permeabilization with non-ionic detergent.
Antibodies binding to the cell surface of intact cultured cells were identified by direct fluorescence using the fluorescence activated cell sorter (FACS), as described by Hellstrom et al., Cancer Research, ~6:3817-3923 (1986). Briefly, for binding analyses using a FACS cell sorter, 1 x 106 cultured cells were aliquoted in 15% fetal bovine serum (FBS) in IMDM media (Gibco, Grand Island, NY) to a total volume of 500 ~l/tube. The cells were centrifuged for 1.5 min on a Serofuge and the supernatant removed. 100 ~l of the Cl monoclonal antibody at 10 ~g/ml and labeled with phycoerythrin was added to each tube, the contents of which was then mixed and incubated on ice for 30 min. The reaction mixture was washed three times with 1 ml of 15~ ~BS/IMDM by centrifugation for 1.5 min. on the Serofuge (tubes were blotted a~ter the third wash). ~ach pellet was resuspended in 500 ~l of PBS.
Each sample was run on a Coulter Epics C FACS and the mean fluorescence intensity (MFI~ was determined. From the MFI, the linear fluorescence equivalent (LFE) was determined. The LFE of each test sample divided by the LFE of a negative control gave a ratio between the brightness of cells stained by specific V5. control antibody (1.0 = no difference in fluoresence, 2.0 =
fluoresence twice as bright, etc.). The binding data is shown in Table 1 below. Phycoerythrin was used as a fluorescent conjugate when attempts to conjugate C1 antibody with FITC were unsuccessful.

Table l Binding of Cl Antibody to Various Cell Lines Cell Lines_l AntibodY Bindinq Ratio RCA Colon carcinoma (ca.)2.6 3347 Colon ca. 76.0 2964 Lung ca. 14.1 2981 Lung ca. 12.4 3606 Lung ca. 2.4 3464 Breast ca. 2.8 3620 Melanoma 1.0 2669 Melanoma 7O4 3614 Melanoma 3.7 Peripheral blood cells 1.0 CEM T lymphocytes l.0 15 Molt-4 T lymphocytes 1.0 P3yHR-1 B lymphoma 1.1 As Table 1 demonstrates, the Cl monoclonal antibody reacted with lung and colon carcinoma cell lines, but did not react with T or B lymphoma lines nor with normal peripheral blood leukocytes. Weak reactivity with 2 of 3 melanoma lines was also observed.

Immunohistology The PAP technique of L. A. Sternberger as described in Immunochemistry, pp. 104-69, John Wiley &
Sons, New York (lg79), as modified by Garrigues et al., Int. J. Cancer, 29:511 15 (1982), was used for immunohistological studies on frozen tissue sections.
The target tissues for these tests were obtained at surgery and frozen within 4 hr. of removal using isopentane precooled in liquid nitrogen. Tissues were then stored in liquid nitrogen or at -70C until used.
Frozen sections were prepared, ai.r-dried, treated with - acetone and dried again (see Garrigues et al., upra).
Sections to be used for histologic evaluation were stained with hematoxylin. To decrease non-specific ~ ~if .. ~ .. L' ~7 backgrounds, sections were preincubated ~lith normal human serum dlluted 1/5 in PBS (see Garrigues et al., supra).
Mouse antibodies, rabbit anti-mouse IyG, and mouse PAP
were diluted in a solution of 10% normal human serum and 3% rabbit serum. Rabbit anti-mouse IgG (Sternberger-Meyer Immunochemicals, Inc., Jarettsville, MD) was used at a dilution of 1/50. Mouse peroxidase-antiperoxidase complexes (PAP, Sternberger-Meyer Immunochemicals, Inc.) containing 2 mg/ml of specifically purified PAP were used at a dilution of 1/80.

The staining procedure consisted of treating serial sections with either specific antibody, i.e., C1, or a control antibody for 2.5 hr., incubating the sections for 30 min. at room temperature with rabbit anti-mouse IgG diluted 1/50 and then exposing the sections to mouse PAP complexes diluted 1/80 for 30 min.
at room temperature. After each treatment with antibody, the slides were washed twice in PBS.

The immunohistochemical reaction was developed by adding freshly prepared 0.5~ 3,3'-diaminobenzidine tetrahydrochloride (Sigma Chemical Co., St. Louis, MO) and 0.01% H22 in 0.05 M Tris buffer, pH 7.6, for 8 min.
(see Hellstrom et al., J. Immunol., 127:57-60 (1981)). Further exposure to a 1%
OSO4 solution in distilled water for 20 min. intensified the stain. The sections were rinsed with water, dehydrated in alcohol, cleared in xylene, and mounted on slides. Parallel sections were stained with hematoxylin.

The slides were each evaluated under code and coded samples were checked by an independent investigator. Typical slides were photoyraphed by using differential interference contrast optics (Zeiss-Nomarski). The degree of antibody staining was evaluated as 0 (no reactivity), ~ (a few weakly positive cells), ++
(at least one third of the cells positive), +-~+ (most cells positive), ++++ (all cells strongly positive).

~ ,ri ~ 3 /q Because differences between + and O staininy were less clear cut than between + and ++ staining, a staining graded as ++ or greater was considered "positive." Both neoplastic and stroma cells were observed in tumor samples. The staining recorded is that of the tumor cells because the stroma cells were not stained at all or were stained much more weakly than the tumor cells.

Table 2 below presents the immunohistological staining of various tumor and normal tissue specimens using the C1 monoclonal antibody. As the table clearly demonstrates, the C1 antibody reacts with human colon and lung carcinomas but not detectably with~cells from breast carcinoma or melanoma; the only ovarian carcinoma sample tested was positive. The C1 antibody shows no reactivity with any of the number of normal human tissues tested.

~ fJ ~ 3~ ;

Immunoperoxidase Staining of Tumors and Normal Tissue Specimens with Cl Monoclonal Antibody Tissue Type AntibodY Binding (Number of Positive Tumors/
Total Number of Tumors Tested) Colon carcinoma (ca.) 9/9 Lung ca. 12/17 Breast ca. 0/14 10 Ovarian ca. 1/l Melanoma 0/6 Sarcoma 1/5 Normal Tissues: SPLEEN 0/4 TONSIL 0/l EXAMPLE III

Cl Antiqen Recoqnized BY Cl Antibody Purification Cl antigen was isolated from colon carcinoma 3347 cells, and from lung carcinoma 2964 cells and partially purified by immunoaffinity chromatography. C1 antigen was purified to homogeneity by SDS-PAGE and recovered from SDS-polyacrylamide gels by electroelution or electroblotting onto membranes.

Following electrophoresis, the SDS-polyacrylamide gel was stained with Coomassie BrilliantBlue and destained. The stained C1 antigen band (Mr =
66,000) was excised with a razor blade and subjected to electroelution.

Cl antigen was also recovered from SDS-polyacrylamide gels by electroblotting onto Immobilonmembrane (Millipore Corp., Bedford, MA) using Mini-Transblot Electrophoretic Transfer Cell (BioRad Laboratories, Richmond, CA), as described by Matsudaira in J. Biol. Chem., 261:10035-10038 (1987). The membrane was stained with Coomassie Brilliant Blue, destained, and the stained Cl antigen band (Mr = 66,000) was excised with a razor blade for subsequent aminoterminal sequence analysis.

Se~uence Analysis Automated Edman degradation was performed on three preparations of C1 antigen with 33 pmol of antigen from 3347 cells, 49 pmol of antigen from 2964 cells, and 6 pmol of antigen from 2964 cells.

The aminoterminal sequence of C1 ankiyen was as follows.

X-E-L-T-I-L-H-T-N-D V-H-S-R-L-E-Q-T-S-X

The aminoterminal sequence of C1 antigen was compared against the following data bases:

Number of Sequences 1. PIR (Release 18.0, Sept. 1988) 8,588 2. GenBANK (Release 57.0, Sept. 1988) 19,044 3. NEW (November 30, 1988) 4,148 4. DIF (November 30, 1988) 2,610 5. SWISSPROT (November 30, 1988) 7,724 6. LOSPRO (November 30, 1988)11,343 The sequence comparison did not reveal significant matches with any other known sequence.

Immunolo~ical Characterization Western Blot Analysis Immunoaffinity-purified Cl antigen was subjected to SDS-PAGE (10~ acrylamide) and electroblotted onto nitrocellulose mem~rane (Schleicher and Schuell, Keene, NH), as described by Towbin et al. in Proc. Nat'l. Acad. Sci. (USA), 76:4350-4354 (1379). C1 antigen was immunodetected using alkaline phosphatase-conjugated rabbit anti-mouse IgG as a second antibody (ICN Biomedicals, Lisle, I~) and 5-bromo-4-chloro-3-indolyl phosphate p-toluidine salt and p-nitro blue tetrazolium chloride as chromogens (BioRad Laboratories).
Immunodetection revealed that the major band at Mr =
66,000 was specifically stained with C1 antibody.
Radioimmunoprecipitation ~J,~ 3~3 33~7 cells were metaholically labeled with 3H-glucosamine by incubation in RPMI 1640 medium (glucose-free RPMI 1640) supplemented with 10%
dialyzed fetal bovine serum for 4 hr. at 37C. The cell pellet was e~tracted with 20 mM Tris-HCl buffer, pH 7.5, 100 mM NaCl, 1 mM EDTA, 0.5~ MP-40, PMSF (10 ~g/ml) aprotinin (10 ~g/ml). C1 antigen was immunoprecipitated by incubating the cell lysate with C1 antibody for 1 hr. at 4C. The antigen-antibody complex was precipitated with goat anti-mouse IgG and Pansorbin (Calbiochem, San Diego, CA).
The washed immunoprecipitate was analyzed by SDS-PAGE under reducing and non-reducing conditions and visualized by fluorography after impregnating the gel with EN3HANCETM.

2964 cells, 2707 cells, CH3T2 cells, and 2981 cells, all derived from adenocarcinomas of the lung, were surface-labeled with 125I by the lactoperoxidase method described by Vitetta et al.
in J. Exp. Med., 134:242-264 (1971). Cl antigen was immunoprecipitated from 125I-labeled cell lysates with Cl antibody, goat anti-mouse IgG, and Pansorbin. The immunoprecipitates were analyzed by SDS-PAGE under reducing conditions and visualized by autoradiography.

C1 antibody specifically precipitated Cl antigen with a Mr of from about 66,000 to 68,000.
These data demonstrate that the antigenic determinant recognized by C1 monoclonal antibody is localized on a unique single-chain glycoprotein with a Mr of about 66,000. The C1 antigen is associated with a variety of tumor cells, particularly lung and colon carcinoma tumors.

~!. ifi It is apparent that many modifications and variations of this invention as set forth above may be made without departing from the spirit and scope.
The specific embodiments described are given by way of example only, and the invention i5 limited only by the terms of the appended claims.

Claims (35)

1. A monoclonal antibody produced by hybridoma cell line ATCC No. HB 9803, which antibody binds to a determinant site on a cell surface glycoprotein antigen of human tumor cells and functional equivalents, binding fragments and immunocomplexes of said antibody.

2. The monoclonal antibody of claim 1 wherein said tumor cells are carcinoma cells.

3. The monoclonal antibody of claim 2 wherein said carcinoma cells are selected from the group consisting of lung and colon carcinoma cells.

4. The monoclonal antibody of claim 1 conjugated to a label capable of producing a detectable signal.

5. The monoclonal antibody of claim 4 wherein the label is selected from the group consisting of a radionuclide, an enzyme, a fluorescent agent and a chromophore.

6. A monoclonal antibody produced by hybridoma cell line ATCC No. HB 9803, which antibody binds to a cell determinant site on a cell surface glycoprotein antigen of human tumor cells, said antigen characterized by a molecular weight of about 66,000 daltons, as determined by polyacrylamide gel electrophoresis, and having an amino terminal amino acid sequence as follows:

in which X represents an unidentified amino acid and functional equivalents, binding fragments and immunocomplexes of said antibody.

7. A composition for treating tumors comprising a therapeutically effective amount of the antibody of claim 6 in association with a pharmaceutically acceptable parenteral vehicle.

8. A monoclonal antibody produced by a hybridoma cell line formed by fusion of a myeloma cell and a cell capable of producing antibody which binds to a determinant on a cell surface glycoprotein antigen of human tumor cells, said antigen having a molecular weight of about 66,000 daltons as determined by polyacrylamide gel electrophoresis, and having an amino terminal amino acid sequence as follows:
in which X represents an unidentified amino acid and functional equivalents, binding fragments and immunocomplexes of said antibody.

9. The monoclonal antibody of claim 8 which is of class IgG.

10. The monoclonal antibody of claim 8 which is of subclass IgG1.

11. The monoclonal antibody of claim 8 which is a murine antibody.

12. A monoclonal antibody reactive with a determinant site on a cell surface glycoprotein antigen associated with human tumor cells, said antigen characterized by a molecular weight of about 66,000 daltons as determined by polyacrylamide gel electrophoresis and having an amino terminal amino acid sequence as follows:
in which X represents an unidentified amino acid, and functional equivalents, binding fragments and immunocomplexes of said antibody.

13. The monoclonal antibody of claim 12 consisting of the monoclonal antibody produced by hybridoma cell line ATCC No. HB 9803.

14. The monoclonal antibody of claim 12 which is a human antibody.

15. The monoclonal antibody of claim 12 which is a mouse-human antibody.

16. A composition for treating tumors comprising a therapeutically effective amount of the antibody of claim 12 in association with a pharmaceutically acceptable parenteral vehicle.

17. An immunoassay for the detection of human tumors comprising:

a) combining a monoclonal antibody reactive with a cell surface glycoprotein antigen associated with human tumor cells, said antigen characterized by a molecular weight of about 66,000 daltons as determined by polyacrylamide gel electrophoresis and having an amino terminal amino acid sequence as follows:
in which X represents an unidentified amino acid, with a sample of tumor cells said antibody labeled so as to be capable of detection; and b) assaying for said labeled monoclonal antibody binding to tumor cells associated with said antigen.

18. The immunoassay of claim 17 wherein said monoclonal antibody is the antibody produced by hybridoma cell line ATCC No. HB 9803.

19. The immunoassay of claim 17 wherein said antibody is labelled with a label selected from the group consisting of a radionuclide, an enzyme, a fluorescent agent and a chromophore.

20. A method for detecting tumors which comprises: contacting the monoclonal antibody of claim 1, 6, 8 or 12 with a human tissue or fluid sample and detecting interaction of said antibody with any antigenically corresponding tumor cells or antigenic determinants thereof in said sample.

21. The method of claim 20 wherein said tumor cells are lung carcinoma cells and the human tissue is lung tissue.

22. The method of claim 20 wherein said tumor cells are colon carcinoma cells and the human tissue is colon tissue.

23. The method of claim 20 wherein the interaction of said monoclonal antibody with said tumor cells is detected by immunohistological staining.

24. A method for localizing human tumors in vivo, comprising:

a) purifying the monoclonal antibody claim 1, 6, 8 or 12;

b) radiolabeling said antibody;

c) administering said antibody to a human patient in a suitable carrier; and d) localizing the monoclonal antibody by external scintigraphy, emission tomography or radionuclear scanning.

25. A method of immunotherapy for the treatment of tumors, comprising:

a) purifying the monoclonal antibody of claim 1, 6, 8 or 12;

b) conjugating said monoclonal antibody to cytotoxic agent, a toxin, or a radiopharmaceutical; and c) administering said conjugated monoclonal antibody to a human tumor patient in a suitable carrier.

26. The method of claim 25 wherein said monoclonal antibody is an anti-idiotype antibody.

27. A continuous cell line which produces a monoclonal antibody, said monoclonal antibody characterized by the capability of binding to a determinant site on a cell surface glycoprotein antigen of human carcinoma cells, which comprises:
a hybridoma of a lymphocyte derived from a mouse immunized with carcinoma cells or an immunogenic determinant thereof and a mouse myeloma cell.

28. A continuous cell line which produces a monoclonal antibody, said monoclonal antibody characterized by the capability of binding to a determinant site on a cell surface glycoprotein antigen of human carcinoma cells, which comprises:
a hybridoma of a lymphocyte derived from a human with carcinoma and a myeloma cell.

29. Hybridoma cell line ATCC No. HB 9803 monoclonal antibody capable of binding to a determinant on a cell surface glycoprotein antigen of human tumor cells.

30. Hybridoma cell line ATCC No. HB 9803 formed by fusing on ATCC CRL 1580, P3 x 63-Ag 8.653 mouse myeloma cell with a mouse splenocyte obtained from a BALB/c mouse immunized with colon adeno-carcinoma H3059 cells which produces a monoclonal antibody which binds to a determinant of cell surface glycoprotein antigen of human tumor cells having a molecular weight of about 66,000 daltons and having an amino terminal amino acid sequence as follows:
in which X represents an unidentified amino acid as determined by polyacrylamide gel electrophoresis.

31. A continuous cell line which produces a monoclonal antibody being characterized by the capability of binding to a determinant site on a cell surface glycoprotein antigen associated with tumor cells, said antigen having a molecular weight of about 66,000 and daltons and having an amino terminal amino acid sequence as follows:
in which X represents an unidentified amino acid, which comprises: a hybridoma of a lymphocyte capable of producing antibody against said antigen and a myeloma cell.

32. A glycoprotein antigen in substantially purified form, said antigen derived from human tumor cells and having a molecular weight of about 66,000 daltons as determined by polyacrylamide gel electrophoresis, and having an amino terminal amino acid sequence as follows:
in which X represents an unidentified amino acid and immunocomplexes of this antigen.

33. A vaccine for use in immunization against tumors comprising a recombinant virus including the DNA coding for the antigen of claim 32.

34. The vaccine of claim 33 wherein said virus is vaccinia virus.

35. A method for immunizing against tumors comprising administering in a therapeutically effective amount of the vaccine of claim 33.