Unusual apparently constitutive interferons and antagonists in human placental blood.

Abstract

Seemingly uninduced interferons (IFNs) were detected in 29/37 human placental samples obtained during caesarean sections at different periods of pregnancy, mostly around the 37th wk. The amounts were usually low and did not enable correlation of findings with any physiological or pathological conditions. Occasionally the presence of IFN was masked by a lectin-like antagonist. In a number of cases, substantially higher amounts of IFN were found after purification by affinity chromatography using concanavalin A, Cibacron blue, or antiserum to IFN-.alpha., each coupled to Sepharose. Analysis by sodium dodecyl sulfate/polyacrylamide gel electrophoresis revealed the presence of IFN-.alpha. and IFN-.beta. with molecular masses between 15 and 80 kilodaltons. Some of the high MW components were neutralized either only by monospecific antiserum to IFN-.alpha. or, to the same extent, by antiserum to IFN-.alpha. or to IFN-.beta., reminiscent of those previously reported after viral induction in the human amniotic membrane. Both IFNs and antagonist apparently play a physiological role during fetal development.