Development of B Lymphocyte Function in Childhood

Abstract

The capacity of blood lymphocytes of children aged from birth to 6 yr to produce Ig was studied in vitro at the cell level using a direct B lymphocyte activator (Epstein-Barr virus) or a T lymphocyte dependent B lymphocyte activator (pokeweed mitogen). Umbilical cord blood lymphocytes secreted IgM at adult levels after Epstein-Barr virus stimulation, while the ability to synthesize IgG and IgA increased up to the ages of 1 and 2 yr, respectively, but not beyond this period. IgG3 production preceded that of the other IgG subclasses. The T lymphocyte dependent IgM synthesis was low at birth, but approached adult levels at 2 yr of age. T cell dependent IgG and IgA secretion, however, remained reduced even up to 6 yr of age.