title: Monoclonal antibodies to early pregnancy factor perturb tumour cell growth.
abstract: The pregnancy-associated substance early pregnancy factor (EPF) has previously been reported as a product of tumours of germ cell origin. More recently EPF (or an EPF-related substance, tEPF) has also been detected in the serum of patients bearing tumours of non-germ cell origin. We report here the production of tEPF by a variety of cultured transformed and tumour cell lines, of both germ and non-germ cell origin. Antibodies specific for EPF remove all tEPF activity from tumour cell conditioned medium. tEPF production is found to be associated with cell division; tEPF is no longer detected after growth arrest or differentiation. Co-culture of tumour cells with increasing doses of anti-EPF monoclonal antibodies resulted in a significant, dose-dependent decrease in rate of cell growth and viability. Similar anti-EPF concentrations had no effect on the concanavalin A induced proliferation of mouse spleen cells. These studies suggest, therefore, that tEPF is a growth-regulated product of cultured tumour and transformed cells. These cells are also dependent upon tEPF for continued growth, i.e. tEPF is acting in the autocrine mode.
authors.affiliation: Department of Surgery, University of Queensland, Royal Brisbane Hospital, Australia.
authors.forename: K A
authors.initials: KA
authors.lastname: Quinn
authors.forename: S
authors.initials: S
authors.lastname: Athanasas-Platsis
authors.forename: T Y
authors.initials: TY
authors.lastname: Wong
authors.forename: B E
authors.initials: BE
authors.lastname: Rolfe
authors.forename: A C
authors.initials: AC
authors.lastname: Cavanagh
authors.forename: H
authors.initials: H
authors.lastname: Morton
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D002455:Cell Division; D018835:Chaperonin 10; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D007166:Immunosuppressive Agents / Q000276:immunology* / Q000378:metabolism; D010452:Peptide Biosynthesis; D010455:Peptides / Q000276:immunology*; D011257:Pregnancy Proteins; D013491:Suppressor Factors, Immunologic; D014407:Tumor Cells, Cultured / Q000276:immunology* / Q000378:metabolism / Q000473:pathology
chemical_list: D000911:Antibodies, Monoclonal; D018835:Chaperonin 10; D007166:Immunosuppressive Agents; D010455:Peptides; D011257:Pregnancy Proteins; D013491:Suppressor Factors, Immunologic; C025124:early pregnancy factor