A MODEL FOR INDUCTION OF T-CELL-INDEPENDENT HUMORAL IMMUNITY IN RESPONSE TO POLYSACCHARIDE ANTIGENS

We provide a model for induction of T cell-independent, polysaccharide -specific Ig secretion in response to bacterial challenge, Two predomi nant pathways are defined that require the concerted action of multiva lent membrane Ig cross-linking by the polysaccharide Ag with 1) variou s B cell-activating moieties contained within the bacterial pathogen a nd/or 2) cytokines, such as IFN-gamma and granulocyte-macrophage colon y-stimulating factor produced by NK cells and macrophages, that become activated in a T cell-independent manner during bacterial infection.