EXPRESSION OF HLA ANTIGENS, BETA 2-MICROGLOBULIN AN ENZYMES BY HUMAN AMNIOTIC EPITHELIAL CELLS

A monolayer of epithelial cells, endowed with unique secretory properties, lines the human amniochorion1,2. It has been shown that transplantation of these membranes into allogeneic hosts does not result in overt acute graft rejection3–6. We demonstrate here that HLA-A, -B, -C and -DR antigens and β2 microglobulin (β2m) cannot be detected by immunofluorescence on freshly collected or in vitro cultured amniotic epithelial cells, although small quantities of such antigens were detected when more sensitive radiobiological techniques were used. We also show that these cells, cultured in vitro, produce large quantities of enzymes absent in patients with lysosomal storage diseases and that their supernatants can correct glycosaminoglycan accumulation in cultured fibroblasts from patients with Hurler's and Hunter's syndromes.