The immune response of offspring mice from mothers immunized during pregnancy with protein antigens

The immune system of offspring mice from mothers immunized with photo-oxidized timothy grass pollen antigen B (OX-AgB) or Trinitrophenyl-bovine gamma globulin (TNP-BGG) during their pregnancy was examined. Offspring mice immunized 6 or 8 weeks after delivery with the same antigen administered to their mothers have completely suppressed primary responses and greater than 80% suppressed secondary responses. The observed immunosuppression in offspring mice appears to persist until about 16 weeks after delivery, and is antigen-specific. Adoptive transfer studies show that spleen cells from adult OX-AgB primed mice injected i.v. into lethally X-irradiated (800 rads) syngeneic recipients and challenged with antigen produce significant levels of AgB-specific IgG antibody. Spleen cells (5 x 10(6] from offspring mice of mothers immunized with OX-AgB during their pregnancy were added to spleen cells from adult OX-AgB primed mice and injected i.v. into lethally X-irradiated syngeneic recipients and challenged with antigen. These recipients showed a significantly (greater than 85%) immunosuppressed secondary response. The observed immunosuppression appears to be mediated by CD4+ and CD8+ T cells suggesting a requirement for both T suppressor inducer and effector cell populations. The reported findings are discussed in relation to possible mechanisms to explain the immunosuppression obtained in the offspring of mothers immunized during pregnancy.