The role of B cells and accessory cells in the neonatal response to TI-2 antigens.

The neonate has an increased susceptibility to infection, in part owing to an inability to produce antibody to thymus-independent antigens such as bacterial polysaccharides (PS). This poor response to PS antigens is likely owing to multiple factors. Neonatal B cells are of an immature phenotype, as evidenced by cell-surface marker characteristics and increased susceptibility to tolerance induction. The spleen of the neonate has a different cellular composition, which is most prominent in the marginal zone. Neonatal accessory cells such as macrophages and dendritic cells (DCs) appear to produce less stimulatory cytokines and an overabundance of inhibitory cytokines. This review examines the current data supporting the role of B cells and accessory cells in the neonatal unresponsiveness to PS antigens.