Complement regulatory proteins at the feto‐maternal interface during human placental development: distribution of CD59 by comparison with membrane cofactor protein(CD46) and decay accelerating factor (CD55)

Abstract

The complement (C) regulatory proteins decay‐accelerating factor (DAF, CD55)and membrane cofactor protein (MCP, CD46), which control C3 convertases, together with CD59, an inhibitor of the membrane attack complex (MAC), were found to be present in the developing human placenta from at least 6 weeks of gestation until term. Immunostaining revealed differences in the distribution of these proteins on the fetally derived trophoblast epithelium, especially in early placentae which contain trophoblast populations of diverse proliferative potential and differentiation status. Expression of all three proteins occurred on the terminally differentiated syncytiotrophoblast epithelium covering chorioni..