ANTIVIRAL NONSPECIFIC IMMUNITY OF HUMAN PLACENTA AT TERM - POSSIBLE ROLE OF ENDOGENOUS TUMOR NECROSIS FACTORS AND INTERFERONS

The antiviral immunity of human placenta and amniotic membrane in an o rgan culture (OC) system was studied. Freshly isolated explants of mos t of the placentas at term and the amniotic membranes were found to be relatively resistant to herpes simplex virus type 1 (HSV-1), encephal omyocarditis virus (EMCV), and vesicular stomatitis virus (VSV) infect ions. After in vitro aging, however, the OC acquired the sensitivity t o the viruses, In about 66%-90% of placentas, resistance of freshly is olated explants to the infection was observed, This indicates that the placentas displayed a constitutive immunity against the viruses, To s tudy the role of endogenous cytokines in antiviral immunity, we added specific antibodies neutralizing IFN and TNF activities to VSV-infecte d OC and checked their influence on viral replication, Increases of 10 -fold to 100-fold of VSV replication in the OC treated with anti-TNF-a lpha, anti-IFN-alpha, anti-IFN-gamma or anti-IFN-beta sera were observ ed, The results indicate the importance of the endogenous cytokines in placental and amniotic membrane immunity, However, we did not observe a simple correlation between the spontaneous IFN and TNF production a nd the level of resistance against viruses, In view of the results, th e participation of TNF and IFN in the constitutively expressed immunit y of human placenta is of a more complex nature.