Transfer of maternal antibodies results in inhibition of specific immune responses in the offspring.

A potentially detrimental consequence of maternally transferred antibodies was demonstrated in a mouse model for rabies virus, where pups from rabies virus-immune dams showed a decrease in the generation of specific B- and T-cell responses to immunization with rabies virus antigen, resulting in vaccine failures. The degree and duration of the vaccine failures was inversely correlated with the amounts of maternally transferred antibodies, and exceeded the time when maternal antibodies provided reliable protection against a viral challenge. The low responsiveness to vaccination, measured by serum antibody titers and by lymphokine release upon in vitro restimulation of in vivo-primed lymphocytes, was specific for the target virus of the maternal antibodies and was also observed in pups from Sendai virus-immune dams upon vaccination with the homologous virus. In addition, an inhibition of the specific immune responses was demonstrated upon passive immunization of newborn mice with monoclonal antibodies to rabies virus. Although the mechanism(s) that causes the observed inhibition in the offspring of immune dams or in pups that were inoculated with antibodies postnatally is currently unknown, data presented in this manuscript indicate that the observed effect on B- and T-cell responses might not be solely caused by removal of the antigenic load due to residual maternal antibodies.