Paradoxical effect of antibodies against chorionic gonadotropin on BeWo choriocarcinoma cells in vitro and in vivo: evidence for heterogeneity of cell types.
Antisera raised in monkey or baboon against purified beta-subunit of human chorionic gonadotropin (beta-hCG) coupled to tetanus toxoid exert complement-dependent cytotoxic effects on BeWo choriocarcinoma cells maintained in tissue culture. The cytotoxic effect is manifested morphologically as well as by incorporation of radioactive thymidine and leucine. However, in the presence of saturating amounts of anti-beta-hCG antibodies and complement, antibodies failed to kill all of the BeWo choriocarcinoma cells. Evidence is presented to suggest that the partial and not complete cytotoxic effect of antibodies may be due to the heterogeneity of cell types, one sensitive to immune attack by anti-beta-hCG antibodies, the other resistant. Immunoenzymatic localization of hCG revealed its presence on the cell surface of only a fraction of BeWo cells. The antibody-resistant BeWo cell population had no demonstrable hCG on the cell surface. Resistant cells did not secrete hCG into the medium when cultured for up to 4 days. However, the resistant cell population, upon transplantation to the hamster cheek pouch, regained the ability to secrete hCG. Heterogeneity of cell types may explain the refractoriness of the BeWo cells transplanted to the hamster cheek pouch to an inhibitory effect of antibodies at later stages of tumor growth.
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D002460:Cell Line; D002610:Cheek; D002822:Choriocarcinoma / Q000276:immunology* / Q000473:pathology; D006063:Chorionic Gonadotropin / Q000032:analysis / Q000276:immunology*; D018997:Chorionic Gonadotropin, beta Subunit, Human; D006224:Cricetinae; D003602:Cytotoxicity, Immunologic; D005260:Female; D006801:Humans; D008253:Macaca mulatta; D008297:Male; D010215:Papio; D010446:Peptide Fragments / Q000276:immunology*; D011247:Pregnancy; D014594:Uterine Neoplasms / Q000276:immunology* / Q000473:pathology
D000906:Antibodies; D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D010446:Peptide Fragments