BIOCHEMICAL AND TOPOLOGICAL ANALYSIS OF ADULT T-CELL LEUKEMIA-DERIVEDFACTOR, HOMOLOGOUS TO THIOREDOXIN, IN THE PREGNANT HUMAN UTERUS

Adult T-cell leukaemia-derived factor (ADF), homologous to thioredoxin , displays various biological activities, such as radical scavenging a ction and the reduction of protein disulphide bonds. We examined the b iochemical and immunohistochemical localization of ADF in the pregnant human uterus, using two heteroantibodies to ADF, antibody C and W. Im munohistochemically, decidua and trophoblast cells were intensely stai ned by antibody C. The concentration of ADF-like substance in the deci dua was 95.9 ng/mg protein, determined by enzyme-linked immunosorbent assay. The molecular weight of ADF-like substance:in these tissues was determined by gel electrophoresis to be 13 kDa, the same as that of r ecombinant ADF. These findings Indicate that abundant ADF is present i n decidua and trophoblast cells; the localization of such a potent dit hiol reducing substance may be beneficial in protecting the fertilized egg and placental trophoblasts from the cytotoxic effects of oxygen r adicals.