Activity of antibodies recovered from immune complexes of ovarian cancer patients

Autologous antibodies eluted from membrane fragments in human ovarian epithelial neoplastic effusions. III. Cytotoxic potential in vitro and characterization of antigen(s)

Cyst and ascites fluids from patients with ovarian epithelial neoplasms contain immunoglobulins with antitumor activity. Autologous antibodies bound to the cellular membrane fragments obtained from human ovarian neoplastic effusions react with cell-surface antigens on different human ovarian cell lines, surgical specimens of human ovarian adenocarcinoma, and human ovarian tumors grown in athymic Balb/c mice. The antibodies do not react with tissue preparations from normal human ovaries, other nonovarian normal or neoplastic tissues, and nonovarian human cell lines. These studies indicate that these antibodies are capable of complement-mediated lysis of human ovarian tumor cell lines in vitro. Preliminary characterization of the autologous ovarian tumor-associated antigen(s) indicates that it may be composed of three large-molecular-weight proteins of 182,000, 164,000, and 122,000 d.

Polyethylene glycol significantly enhances the transfer of membrane immunoblotting

Poly(ethylene glycol)n is a group of water-soluble, hydrophobic, optically transparent and biomacromolecule-nondenaturing polymers. These properties have caused it be widely used for various purposes in the biological sciences. In this study, the effects of poly(ethylene glycol)n on protein preservation, electrotransferring, and immunoblotting from sodium dodecyl sulfate (SDS)-polyacrylamide gel onto polyvinylidene difluoride (PVDF) membrane have been systematically evaluated. After SDS-polyacrylamide gel electrophoresis, 30% poly(ethylene glycol)n may be applied to reversibly fix proteins within the gel more completely, differing from irreversible fixation produced by solutions such as trichloroacetic acid-sulfosalicylic acid or acetic acid-methanol systems. The intragel proteins, fixed by poly(ethylene glycol)n, can be electroblotted directly onto PVDF membranes in the presence of 30% poly(ethylene glycol)n. We have shown that treatment with poly(ethylene glycol)n may reduce background, raise signal-to-noise ratio, sharpen protein bands, and increase resolution, resulting in enhancement of the immunoblotting transfer. It is possible to visualize a few picograms of a single protein band, increasing the sensitivity of the method by 10- to 100-fold, as compared with standard immunoblotting techniques.

Ovarian cancer-associated antibodies recovered from ascites: their use for the isolation of ovarian cancer-associated antigen to produce monoclonal antibodies

Immune complexes (ICs) were recovered from the ascites of a patient with stage IV endometrioid ovarian cancer by sequential precipitation with 33% saturated ammonium sulfate and 2.5% polyethylene glycol 6000 (PEG 6000), followed by affinity chromatography on protein A-Sepharose CL-4B. The IgG-containing ICs were dissociated using 8 M urea, separated by ion-exchange chromatography on Sephadex QAE-50, and subsequently analyzed for purity by immunoelectrophoresis (IEP) and radial immunodiffusion (RID). Recovered antibody was tested for reactivity by immunohistologic techniques against paraffin-embedded tumor tissue and acetone-fixed cell suspensions of epithelial tumors. The antibody which demonstrated ovarian cancer-associated activity was absorbed with antigen extracts of breast, colon, and lung cancers as well as keratin to reduce cross-reactivity. The absorbed endometrioid ovarian cancer-associated antibody (OCAAb) was used to produce an immunoadsorbent column for the recovery of tumor-associated antigens. A mouse monoclonal antibody designated FEN-1 was produced using this antigen-containing fraction, and preliminary screening has demonstrated ovarian tumor-associated reactivity. The use of autologous ICs as reagents for preparing tumor antigen-rich immunogens may provide a valuable tool in the search for tumor-associated antigens.

Detection of human ovarian tumor-associated antigens by antibodies isolated from ovarian carcinoma ascitic fluid

Ascitic fluid from patients with ovarian epithelial cancer contains large amounts of soluble immune complexes and is a potential source of antibodies and antigens associated with the tumor. The antibodies against tumor-associated antigens were purified from the ascitic fluids of patients with ovarian serous cystadenocarcinoma. These antibodies showed specificity toward ovarian epithelial cancer when tested against ovarian tumor cell lines and paraffin-embedded tissue sections of ovarian cancer. The antigens in sera of patients were separated from IgG and IgG complexes by affinity chromatography and the free antigens were isolated. With the antibodies purified from ascitic fluid, the levels of tumor-associated antigens in sera of 10 patients with serous cystadenocarcinoma and 12 control patients were detected by an enzyme-linked immunosorbent assay. The antigens in patients with ovarian epithelial cancer were 2 to 10 times higher than those in control patients. These studies demonstrate that the antibodies isolated from ascitic fluid detect the tumor-associated antigens on tumor cells as well as the shed antigens present in serum.

Circulating immune complexes as an immunological marker in premalignant and malignant lesions of the oral cavity

Circulating immune complexes and their immunoglobulin contents were estimated in the sera of 50 patients with oral leukoplakia, 50 patients with oral submucous fibrosis and 50 oral cancer patients. The values were compared with that of 50 normal controls. The circulating immune complexes and their immunoglobulin contents were found to be elevated significantly both in oral submucous fibrosis and oral cancer. This study seems to be of help in monitoring the malignant transformation of oral submucous fibrosis to oral cancer.

Ovarian tumor antigens: preliminary histological investigation

The immunoglobulin IgG was isolated from the immune complexes obtained from the ascitic fluids of patients with ovarian serous cystadenocarcinoma. The IgG isolates did not react in immunoperoxidase staining of normal ovarian, fallopian tube, or endocervical tissue. In contrast, the IgG isolates did react in immunoperoxidase staining of autologous and allogeneic ovarian cancer tissue. However, the staining was variable in terms of areas of positivity and was completely absent in some serial sections. This variability was also evident in control sections of an ovarian mucinous cystadenocarcinoma that was positive for the carcinoembryonic antigen. In addition, it appears that serous and mucinous ovarian cancers may share common antigenic determinants. These results demonstrate the antigenic heterogenous nature of ovarian cancer.

Isolation and dissociation of immune complexes from pleural effusions of lymphoma patients

Immune complexes (IC) isolated from pleural effusions of lymphomas with favorable and unfavorable prognoses were of IgG type. These IC were further dissociated by ion exchange chromatography using 8 M urea. The antibody was found to be a high molecular weight protein (1.5 X 10(5) daltons) and reacted with antihuman IgG immunologically while a second peak obtained on ion exchange chromatography may be an antigen moiety with a molecular weight of 3.2 X 10(4) daltons as it reacted immunologically with the antibody. Strong cytoplasmic fluorescence was observed with various cell suspensions of lymphomas when reacted with the antibody preparations. The antisera raised against two different antigen fractions prepared from two lymphomas--nHL and LL showed positive fluorescence with both nHL and LL suspensions. The absorption of these rabbit antibodies with individual cell extracts or with antigen preparations also entirely blocked the cytoplasmic staining. The antigen moiety (PK-II) may have a common origin in the disease process. Pleural effusions from patients with unfavorable and favorable prognoses showed identical patterns of separation of IC components.

Autologous antibodies eluted from membrane fragments isolated from the effusions of human ovarian epithelial neoplasms. I. Quantitation of antibodies

Cyst and ascites fluids from patients with ovarian epithelial neoplasms contain large amounts of soluble immunoglobulins without detectable antibody activity against human ovarian tumor cell lines by indirect immunofluorescence. Membrane fragments were prepared from 56 human ovarian effusions, and the presence of membrane-bound IgG, IgA, and IgM was demonstrated. The predominant membrane-bound immunoglobulin class was IgG, which ranged from 18 to 4275 ng/ml on samples tested, whereas IgA was present in the range of 5 to 52 ng/ml. The autologous membrane-bound antibodies strongly recognized cell-surface antigens on four human ovarian cell lines and four surgical specimens of human ovarian adenocarcinoma but did not react with normal human ovaries, non-ovarian normal and neoplastic tissues, or non-ovarian human cell lines by indirect immunofluorescence assay. These studies indicate that patients with ovarian cancer have the capability of recognizing and forming antibodies against autologous ovarian tumor-associated antigens.

Quantitation of immunoglobulins in the effusions of human ovarian epithelial neoplasms

Cyst and ascites fluid was obtained from 31 different patients with ovarian epithelial neoplasms and was analyzed for the molecular forms and quantities of IgG, IgM, and IgA. The fluids were grouped on the basis of the pathologic diagnosis of the tumor tissue for investigation of the possibility that immunoglobulin levels in fluids from ovarian neoplasms varied with the type of tumor. Immunoglobulin concentrations in most cyst fluid samples were comparable to amounts detected in normal human serum; however, significant reductions in the amounts of IgA in fluids from mucinous cystadenocarcinomas and in the amounts of both IgA and IgM in fluids from mucinous cystadenoma were demonstrated. The cyst fluid immunoglobulins were present in the same molecular forms as serum immunoglobulins, that is, pentameric IgM, predominantly monomeric IgA, and monomeric IgG. The usefulness of cyst effusions as a source of autologous antibodies in the investigation of the immune response to tumors is discussed.