Effects of immunization of mothers on the immune reaction of their offspring. II. Significance of enhanced antigen elimination by maternal antibodies on the suppression of the offspring.

In the offspring of sheep erythrocyte (SRBC)- or chicken erythrocyte (CRBC)-immunized mothers, generation of cytotoxicity and plaque forming cells (PFC) were suppressed, while delayed-type hypersensitivity (DTH) was not. We performed experiments to analyse the mechanism of this suppression. Antigen specific antibodies, which enhanced opsonization or antibody-dependent cell-mediated cytotoxicity (ADCC), might have a close relation to the suppression (1). The suppression was weakened by a high-dose of antigen challenge or macrophage blockade with colloidal carbon, while enhanced by macrophage activation with Corynebacterium parvum. In contrast, secondary immune responses in the offspring showed the same amplitude as in normal mice. Therefore, the suppression in the offspring might be a result from the early antigen elimination by enhanced opsonization or ADCC due to passive antibodies. But, generation of memory cells or effector cells of DTH might not be affected in the presence of passively transferred antibodies.