H5D12 monoclonal antibody identifies a 24-kD immunosuppressor factor produced by human chorio carcinoma cells.
OBJECTIVE
The purpose of this study was to identify and characterize embryo-associated immunosuppressor factor (EASF) secreted by chorio carcinoma cells with the help of EASF-specific monoclonal antibody H5D12 (raised against EASF purified from embryo growth media of in vitro fertilized human ova).


METHODS
Paraffin-embedded slides of human chorio carcinoma as well as control cell lines were prepared, and immunohistochemistry was done by the avidin-biotin-peroxidase technique. EASF was affinity purified using H5D12-Sepharose 4B from culture media of cell lines and analyzed for immunosuppressive activity (by Concanavalin-A-induced lymphocyte proliferation assay) and molecular weight identity (by metabolic-labelling studies with 35S-methionine followed by immunoprecipitation and SDS-PAGE).


RESULTS
H5D12 showed intense immunostaining of BeWo chorio carcinoma cells. Biosynthetic labeling studies identifies this factor as a 24-kD molecule, and EASF bioassay indicates that this factor possesses immunosuppressive activity. No such immunosuppressive activity or similar molecules were identified when control cell lines were analyzed.


CONCLUSIONS
Monoclonal antibody H5D12 recognizes a 24-kD factor with immunosuppressive activity that is secreted by chorio carcinoma cells, which suggests that this is a unique factor and may be one of the key regulators of reproductive functions.
Bose
R
R
Department of Obstetrics, Gynecology and Reproductive Sciences, University of Manitoba, Winnipeg, Canada.
Berczi
A
A
D000911:Antibodies, Monoclonal / Q000276:immunology*; D002822:Choriocarcinoma / Q000276:immunology*; D002847:Chromatography, Agarose; D017077:Culture Media, Conditioned; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D011233:Precipitin Tests; D011247:Pregnancy; D013491:Suppressor Factors, Immunologic / Q000032:analysis* / Q000276:immunology; D014407:Tumor Cells, Cultured; D014594:Uterine Neoplasms / Q000276:immunology
D000911:Antibodies, Monoclonal; D017077:Culture Media, Conditioned; D013491:Suppressor Factors, Immunologic