Decidua-associated suppressor activity and viability of individual implantation sites of allopregnant C3H mice

Release of soluble suppressor activity from individual implant site decidua of DBA/2-mated C3H/HeJ mice was measured on days 12.5-13.5 of pregnancy. Suppressor activity varied among sites and followed a distribution curve that was displaced towards low suppression when resorption sites were compared to healthy embryonic implants. Pre-immunization against the DBA/2 strain paternal antigens failed to increase resorbtion (by loss of low suppression implants) but led instead to a reduced resorbtion rate. This was associated with an increase in soluble suppressor activity obtained from decidua. Some reduction in resorbtion occurred independent of an increase in the level of suppression suggesting additional contributing factors to the immunization effect.