Maternal antibodies in human foetal sera at different stages of gestation

Abstract

Complement-fixing antibodies to ten viral antigens and/or mercaptoethanol treated anti-streptolysin-O and anti-staphylolysin-α were determined in thirty human sera from foetuses at different stages of gestation, in fifty-seven full-term cord sera, and in the corresponding maternal sera. In the smallest foetuses (crown—heel length of 125–150 mm), no antibody was found. In those of length 155–215 mm, antibody was detectable if the corresponding maternal value was high. In foetuses of 230–380 mm, antibody was detected occasionally even when the maternal value was low. Sera of foetuses of 390 mm or more contained the same antibodies as the maternal sample, and foetal titres sometimes exceeded those of the mother. Titres in the full-term cord sera were significantly higher than the maternal titres for seven of the twelve antibodies studied.