Pregnant and pseudopregnant mice produce a low cytotoxic alloantibody response when challenged by fetal but not adult F1 alloantigens

Antibody isotype produced by pregnant mice immunised with fetal allogeneic lymphocytes is mainly IgG1

Virgin and Pregnant BALB/c mice were immunized three times with (BALB/c X CBA)F1 fetal or adult lymphocytes. An enzyme linked immunosorbent assay (ELISA) was developed for analysing the isotypes and specificities of the alloantibody produced. Pregnant mice immunized with fetal lymphocytes showed an immunodeviation towards IgG1 production compared with other groups.

Maternal humoral immune response to incompatibility at multiple minor histocompatibility loci in mice

Mice of the H-2b haplotype were mated with males of the same MHC haplotype, but differing at multiple minor histocompatibility loci. Mice were bled during each pregnancy and at 2-day intervals post-partum. The sera were assayed by indirect immunofluorescence for evidence of a humoral immune response to paternal minor histocompatibility antigens. Alloantibody was first detected in the post-partum period following the third pregnancy, and was also detected during the fourth pregnancy. Thereafter, alloantibody levels dropped and by the post-partum period following the fifth pregnancy, fell to control values. Assays on a panel of cells from mice of different inbred strains revealed specificity of the alloantibody to H-3.1, H-4.1 and H-7.1 antigens. A conventional dye exclusion cytotoxicity test revealed the pregnancy-induced alloantibody did not exhibit complement-dependent cytotoxicity. These findings are discussed in relation to the regulation and functional significance of the humoral immune response in allogeneic pregnancy.

Collagen-induced arthritis and pregnancy in mice: the effects of pregnancy on collagen-induced arthritis and the high incidence of infertility in arthritic female mice

Collagen-induced arthritis (CIA) in mice is a model of inflammatory polyarthritis that has many features similar to human rheumatoid arthritis. In rheumatoid arthritis, pregnancy leads to amelioration of the disease while exacerbation develops after delivery. We used the CIA model to elucidate the role of pregnancy on disease and vice versa. The onset of arthritis in pregnant mice was delayed in the B10.RIII strains immunized with native porcine type II collagen 7-12 days prior to syngeneic [B10.RIII (susceptible to CIA) X B10.RIII] and allogeneic (B10.RIII female X B10.K male that are CIA resistant) pregnancy. In contrast, when mice were immunized on days 1-6 of pregnancy, the onset of arthritis was earlier as compared with controls. In addition, once the mice developed CIA after delivery, the disease showed markedly rapid progression as compared to the control immunized group. Humoral immune responses to type II collagen showed significantly decreased levels on day 14 (at late stage of pregnancy) both in syngeneic and allogeneic postmating immunized pregnant mice. The same effect was also seen in allogeneic premating immunized pregnant mice on day 21 (at mid-stage of pregnancy). The levels of these antibodies increased after delivery. Subclasses of IgG1 and IgG2a antibodies to type II collagen were suppressed during pregnancy. In the pseudopregnant group, these antibodies showed decreased levels on day 14, but did not differ from the control groups on day 21 and 28. Some immunoregulatory changes may play a role in these alterations in pregnant arthritic mice. In comparison to the effects of syngeneic (susceptible X susceptible) pregnancy on CIA, allogeneic (susceptible female X resistant male) pregnancy seemed to be beneficial for the affected individuals. Litter size and mean birth weight were not affected by immunization of type II collagen. After onset of CIA, both syngeneic and allogeneic matings failed to produce offspring in arthritic female mice. The estrus cyclicity was highly disturbed in arthritic female mice and gonadotropin stimulation in arthritic mice induced significantly less ova in oviducts and maturing follicles as compared to nonarthritic controls. Immunological factors yet to be elucidated may be involved in this ovarian dysfunction.