Abstracts (first author)
Maternal immune challenges exert both enhancing and suppressive effects on offspring immune responses
Maternal antibodies can both enhance and suppress offspring humoral immune responses. However, these enhancing and suppressive effects have typically been documented in separate studies conducted with different species and different antigens over variable time periods. Thus the conditions that induce a priming effect of maternal immune challenge versus a suppressive effect have been unclear. In this study, we exposed female zebra finches (Taeniopygia guttata) and their offspring to one of two antigens (keyhole limpet hemocyanin (KLH) or lipopolysaccharide (LPS)) or a control treatment and quantified maternal antibody transmission and endogenous offspring antibody production. Antigen-specific maternal antibodies reached their lowest levels between days 17 and 28 post-hatch and total antibody concentrations peaked at day 17 post-hatch. We found that both maternal KLH and maternal LPS exposure stimulated the production of antigen-specific antibodies in non-challenged offspring after the catabolism of maternal antibodies. This suggests a stimulatory effect of maternal immune challenge on offspring humoral immunity. However, offspring of both KLH and LPS challenged mothers exhibited weaker antigen-specific secondary immune responses when mothers and offspring were challenged with the same antigen. Maternal immune challenge did not impact the ability of young to respond to the other antigen. This supports a specific, suppressive effect of maternal immune challenge on offspring antibody production. Thus, maternal antibodies can have an instructive role, potentially acting as internal antigens, and stimulate offspring antigen-specific antibody production in response to two distinct antigens. However, when the early antigenic environment of offspring is similar to the maternal antigenic environment, maternal antibodies may suppress the endogenous antibody responses of young.