Influence of transplacentally acquired antibody on neonatal susceptibility to canine distemper virus in gnotobiotic dogs.

In utero acquistion of protective levels of neutralizing antibody to canine distemper virus (CDV) was observed in four litters of colostrum-deprived gnotobiotic and specific-pathogen-free puppies. Pregnant bitches with high antibody titers passively transferred antibody to these pups transplacentally in average titers of 1:7 to 1:16 per litter. Maternally derived antibody protected neonatal pups from otherwise fatal infection with virulent CDV. Protection was associated with a transient lymphopenia and viremia and temporary suppression of lymphocyte responses to phytohemagglutinin-P.