Effect of Fetal or Neonatal Immunization on Antibody Response of the Adult Rat.

Abstract
Rats were immunized with washed sheep erythrocytes 7 days before birth or 1 day post-natally. These animals as well as suitable controls received a single injection of sheep erythrocytes at 9-10 weeks of age. The rats which were exposed to the erythrocytes during the prenatal or perinatal period exhibited an undiminished capacity for hemolysin production as compared to the controls. The disparity between these results and those of other investigators who induced immunologic paralysis or actively acquired tolerance is considered in the light of quantitative considerations rather than in terms of qualitative alterations in the antigen-host relationship.