Antibody can mediate protective immunity at early tissue-dwelling stages of intestinal helminth infection (37.27)

Abstract

Abstract B cells may be critical in mediating protective immunity by aiding Th2 cell development and/or antibody production. To examine the role of B cells during helminth infection B cell-deficient mice were inoculated with one of two intestinal nematode parasites: Nippostrongylus brasiliensis (Nb) and Heligmosomoides polygyrus (Hp). A similar pattern in elevation of Th2 cytokine gene expression was seen in B cell-deficient and WT mice after inoculation with either species. No difference in worm expulsion was found between B cell-deficient and WT mice after Nb infection, but differences in worm expulsion occurred after Hp inoculation. At day 4 and day 7 after secondary Hp challenge impaired larval migration and development occurred in WT but not B cell-deficient mice suggesting that both early invasion and in situ larval development were inhibited through B cell-dependent mechanisms. Administration of immune serum to B cell-deficient mice restored protective immunity and when given to naïve mice mediated protective effects, suggesting a primary role for antibody in protective immunity during Hp infection. Thus, these data indicate that B cells contribute to protective immunity during Th2-types responses primarily through their production of antibodies and that their importance varies among different species of intestinal helminthes.