Cell-mediated lympholysis by human maternal and neonatal lymphocytes: mother's reactivity against neonatal cells and vice versa.

Maternal reactivity in cell-mediated lympholysis (CML) against cells from her own child is, in average, half of the maternal reactivity against unrelated adult cells. This finding remains the same when cells from a newborn or from an older child are used, suggesting that the reduced maternal reactivity is based rather on the one haplotype identity between the mother and child than on the occurrence of specific maternal tolerance. Consistently, CML-capacity of the child, directed against cells of own mother, is half of the control values, again independently of the child's age.