Distribution of beta2 microglobulin and HLA in chorionic villi of human placentae.

Abstract

ANALOGIES are often made between transplantation and placental immunology. The role of histocompatibility antigens is of undisputed importance in transplantation immunology but it is not clear whether such antigens are important in pregnancy. Indeed, it is not known whether trophoblasts manifest histocompatibility antigens. If HLA antigens are relevant in pregnancy, it is of central importance to know if trophoblasts have these antigens. This is a difficult problem because human anti-HLA sera often contain other antibodies, and heterologous anti-HLA sera often lack precise HLA specificity1. But HLA has been shown to be invariably associated with β2-microglobulin2, and here we present data in support of the concept that human trophoblasts contain neither β2 microglobulin nor HLA. Also, treatment with several enzymes has failed to reveal these antigens. In addition, we have not been able to identify either β2 microglobulin or HLA on trophoblasts from 6-week or 13-week placentae or on placental tissues maintained in vitro for 5 d.