Abstract
Of 851 [human] full-term pregnancies, 169 with lymphocyte cytotoxic antibody activity were found. A rise in incidence of antibody activity was found through 1st, 2nd and 3rd pregnancies. The average scores for antibody titer and avidity were similar for antibodies to the [HL-A] A and B loci in 1st, 2nd and 3rd pregnancies although individual scores varied greatly. Five cases are reported where antibody activity was not detectable till the 6-mo. post-natal stage. ABO compatability did not have any effect on antibody production. A further 40 placental eluates are reported with the same findings as reported previously.