Immunoactive products of placenta: VIII. Translation products of messenger RNA extracted from murine placenta or A6B9IC5 teratocarcinoma are immunosuppressive in vitro.

RNA was extracted from placentae of synpregnant C3H mice (day 14 of gestation) and from A6B9IC5 teratocarcinoma. After isolation of poly-(A)+ RNA on an oligo d(T) cellulose column, putative messenger RNA was injected into Xenopus laevi oocytes. Supernatants and homogenates from the oocytes were assayed for immunoregulatory activity in MLR, CML, and NK assays and found to be immunosuppressive. These data indicate that immunomodulators could be obtained from the placenta by molecular biology technology in sufficient quantities for eventual clinical applications.