In vitro foeto-maternal lymphocyte responses at delivery: no gross changes in MLC and PLT responsiveness.

The reactivity of peripheral blood mononuclear cells of mothers and their newborns in mixed lymphocyte cultures (MLC) and primed lymphocyte typing (PLT) was tested. The primary MLC tests did not demonstrate any altered kinetics or suppression of the mother's lymphocytes towards the cells of her newborn, or vice versa. In most cases, the bidirectional MLC between maternal and newborn cells was found to be normal. Maternal lymphocytes could, however, be primed in vitro to cells from their newborn, and demonstrated a somewhat better specificity for HLA-D determinants than paternal cells similarly primed, indicating that some priming may have occurred in vivo during pregnancy.