Effects of maternal allergen-specific IgG in cord blood on early postnataldevelopment of allergen-specific T-cell immunity

Background: A wide body of epidemiologic evidence indicates that as yet unk nown maternal factor(s) can influence susceptibility to allergic disease in the offspring. It is also well established that the induction of allergen- specific T-cell memory is frequently initiated in utero, and it is likely t hat maternal factors exert their influence during this period. Methods: This study examines the relationship between maternally derived al lergen-specific IgG subclass antibodies and cellular immune responses (lymp hoproliferation and cytokine production) against the same allergens in 49 s ubjects tested at birth and at 2 years of age. Polyclonal production of the Th1 cytokine IFN-gamma was also examined in the cord-blood samples. Results: At birth, then were positive correlations between both house-dust mite (HDM)- and ovalbumin (OVA)-specific IgG subclass levels in cord blood, maternal atopy, and the magnitude of perinatal lymphoproliferative respons es to respective allergens. Inverse relationships were also observed betwee n cord-blood IgG antibody titres and allergen-specific production of some T h2 cytokines. However, there were no consistent relationships between cord- blood allergen-specific IgG antibodies and subsequent immune responses to a llergens when the same subjects were retested at 2 years of age. An inverse relationship was observed between maternal history of atopy and perinatal IFN-gamma production capacity. Conclusions: Our results suggest that transplacental transfer of allergen-s pecific IgG antibody is unlikely to be a major mechanism for maternal regul ation of allergen-specific immunity in infancy. An alternative possibility is that maternal effects may operate by influencing IFN-gamma production by T cells in the offspring.