PRODUCTION OF INTERLEUKIN-6 BY NORMAL HUMAN TROPHOBLAST

The placenta plays a number of important roles during pregnancy, some of which might be mediated by cytokines with multiple activities such as IL-6. Using an IL-6-dependent cell line, MH60·BSF2, we showed that the placenta released IL-6 into the culture supernatant. Analysis of single-cell suspensions of placental cells determined the major source of IL-6 to be trophoblast. Using a mouse monoclonal antibody specific for IL-6 (αBSF2-166), immunohistochemical analysis of placental specimens demonstrated the localization of IL-6 only in the trophoblast layer. Additional immunocytochemical studies with single-cell suspensions of trophoblasts demonstrated the preferential presence of IL-6 molecules in syncytiotrophoblasts rather than cytotrophoblasts. The evidence that a high titer of IL-6 is produced spontaneously by syncytiotrophoblasts indicates that IL-6 may play immunological roles in fetomaternal interactions by means of IL-6-driven multiple immunoregulatory activities. © 1990, Baillière Tindall. All rights reserved.