Production and characterization of monoclonal antibodies to embryo-associated immunosuppressor factor (EASF) produced by human pre-implantation embryo.

Balb/c mice were immunized with pre-implantation embryo-associated immunosuppressor factor (EASF) (purified from embryo growth media of in vitro fertilized human ova). Hybridoma clones were produced by fusing their spleen cells with NS1 and P3X653 myeloma cell lines. The presence of specific anti-EASF monoclonal antibodies (mAb) in the hybridoma culture supernatants were tested by enzyme-linked immunosorbent assay. A total of 15 hybridoma clones were selected, and their products were purified and characterized. Each mAb bound specifically to its antigen in a dose-dependent manner. The affinity-purified EASF from embryo growth media demonstrated immunosuppressive activity on Concanavalin A-induced lymphocytes and the presence of 14 kDa, 24 kDa and 37 kDa factors. No such activity or similar molecules were identified when control growth media were analyzed. This clearly demonstrates that these mAb are indeed EASF-specific and are able to recognize biologically active immunosuppressive components in embryo growth media. These mAbs are presently being tested for the development of EASF-specific assay system.