Humoral immune responses in murine pregnancy. I. Anti-paternal alloantibody levels in maternal serum.

The kinetics and properties of anti-paternal alloantibody produced by female C57BL(H-2b) mice in response to mating with CBA(H-2k) males have been investigated using an immunobead adsorption assay. No alloantibody was ever detected in the first pregnancy or post-partum period. 72% of females exhibited a humoral response in their second pregnancy, detectable from day 16 or 17 post-coitum, and almost all females responded in their third pregnancy. Column chromatographic and immunoelectrophoretic analysis showed that the alloantibody was IgG. Although passive transfer experiments suggested similar stability characteristics to those of cytotoxic antibody induced by experimental hyperimmunization, the pregnancy-induced alloantibody did not exhibit complement-dependent cytotoxicity. The findings are discussed in relation to the nature of the immunogenic stimulus from the conceptus and the regulation and possible function of the humoral immune response in allogeneic pregnancy.