Anticollagen antibody responses in DBA/1 (H-2 q) mice associated with type II collagen-induced arthritis and the effect of pregnancy

Abstract

We have previously shown that DBA/1 mice immunized with heterologous type II collagen showed remission of the subsequent collagen-induced arthritis (CIA) when pregnant, but experienced exacerbation postpartum. Measurement of anticollagen antibody (aCa) responses by ELISA in primiparous mice immunized at day 1 of pregnancy revealed no significant difference compared to aCa titres in virgin animals, apart from slightly increased titres following the primary immunisation. When mice received collagen challenge during early pregnancy, however, the date at which maximal antibody titres was reached was delayed by 5 days. Pregnancy initiated following the intraperitoneal boost caused a ten-fold suppression in aCa titres with a rise post-partum. Measurements of aCa levels in individuals which showed fetal resorption indicated that suppression of humoral responses was dependent on the presence of a viable conceptus. Antibody titres declined in all animals after a period of time, which was more prolonged in multigravidae where aCa titres were higher than in nulliparous and primiparous mice. The results show that although pregnancy alters aCa responses during the course of gestation, no long-term modification of humoral immunity occurs, an observation in agreement with the clinical findings in these mice and in humans.