Allopregnancy in B-cell deprived C57/Bl mice — An investigation focusing on the relationship between survival of the fetuses and anti-paternal immune activity of the mothers

Abstract C57/Bl female mice (haplotype H2-b) were treated throughout their life cycles with rabbit anti-mouse IgM antibodies in order to remove all maturing B-lymphocytes. At an age of 40 days the B-cell-deprived mice and the corresponding controls were allowed to mate with CBA/Ca males (haplotype H2-k). Four groups of allopregnant animals were investigated: (A) mice not subjected to further treatment, which were allowed to pass through a first pregnancy, (B) mice not subjected to further treatment, which were allowed to pass through a first and second pregnancy, (C) mice immunized with paternal cells prior to mating and then allowed to pass through a first pregnancy, (D) mice which during their first pregnancy were given transfusions of anti-paternal lymphocytes obtained from hyperimmune virgin donors. All animals were dissected on the calculated day for parturition (or the first day that abortions or resorptions were detected). On conclusion of the experiments, the efficiency of the anti-IgM treatment was defined for each mouse, using three different methods (ELISA for detection of serum IgG, immune staining for detection of surface Ig-carrying cells, and the protein A plaque assay for detection of Ig-secreting cells). The T-cell function was recorded in vitro by ConA responsiveness. In addition, control animals were assayed for anti-paternal serum antibodies. In experiments (A), (B) and (C), B-cell-deprived mice and corresponding controls were equally successful in passing through pregnancy, having fairly similar litter sizes and resorption frequency. In group (D), however, some of the anti-IgM-treated mice resorbed all her fetuses. Those that gave birth at on schedule had a resorption frequency and litter size fairly similar to those of the controls.