Immunization of the neonate

The generation of diversity of T and B cells begins early in gestation. Selective restrictions in expression of V genes occur in fetal life, but insufficient clonal diversity is not likely to limit newborn immune capabilities. The functional immaturity of neonatal T and B cells is beginning to be defined. Virgin T cells lack the capacity to produce diverse lymphokines, whereas neonatal B cells are less responsive to the lymphokines that promote terminal differentiation to plasma cells.