PROBLEM: The structure and protective activity of antibodies against tetanus (anti-T) and diphtheria (anti-D), produced during human pregnancy and transferred to new-born, was studied.
METHOD: Antibody levels were measured by ELISA in non-pregnant women (control group), primiparae, and multiparae, and in their children. The proportion of symmetric and asymmetric IgG molecules was determined and their respective protective capacity evaluated.
RESULTS: The quantity of asymmetric anti-T and anti-D antibodies in mothers at the time of delivery was roughly four- and three-fold that of the control group, respectively, dropping significantly 1 month later. A similar proportion of these antibodies was observed in the new-born. The lower neutralizing capacity of asymmetric molecules was demonstrated in vivo.
CONCLUSION: Results show that during pregnancy there is a modulation of the immune response with an increase in the production of asymmetric molecules of lower protective capacity.