TRANSFER OF CELL MEDIATED IMMUNITY (CMI) TO THE FETUS

Abstract

Previous evidence of transfer of CMI to the fetus (Field & Caspary, Lancet 2: 337, 1971) was limited to in vitro demonstration of sensitivity in mononuclear cells (MC) of mother and newborn to purified protein derivative (PPD). If such transfer indeed occurs, it could theoretically reduce the efficacy of BCG immunization given often shortly after birth. We examined MC response from mothers and their infants, using PPD (Connaught), Candida extract (Hollister Stier) and/or streptokinase streptodornase (SKSD) (Lederle) as mitogens. The response was measured by tritiated thymidine incorporation on the 6th day in triplicate microcultures, containing 2×105 MC in 15% autologous or pooled AB serum and RPMI medium. The stimulation index (SI) (CPM of stimulated divided by CPM of unstimulated cultures) was used to determine positive (SI>2.5) or negative responses. Of 63 mothers with a positive response to PPD, 22 infants were positive. Of 46 mothers positive to Candida, 17 infants were positive to Candida. Of 27 mothers positive to SKSD, 9 infants were positive to SKSD. Mothers with negative responses to any of the antigens had infants negative to the same antigens. Positive responses in infants persisted for at least 3 weeks in all infants tested but eventually all were negative. Karyotyping of male newborns' MC stimulated with specific antigens revealed that the transformed cells were of XY karyotype. We conclude that specific CMI is indeed transfered from mother to fetus. This may be an important argument to postpone BCG immunization till after the newborn period.