Effects of group B streptococci on cord and adult mononuclear cell interleukin-12 and interferon-gamma mRNA accumulation and protein secretion

Group B streptococci (GBS) are a major cause of early-onset infection in ne onates, Neonates, who have defects in neutrophil function that likely contr ibute to susceptibility to GBS infection, are deficient in the production o f the phagocyte activator interferon (IFN)-gamma. GBS-stimulated mRNA accum ulation and protein secretion of IFN-gamma and interleukin (IL)-12, a major enhancer of IFN-gamma production, by mixed mononuclear cells (MMCs) from u mbilical cord and adult peripheral blood was examined. GBS-exposed cord blo od MMCs secreted lower concentrations of both IL-12 and IFN-gamma proteins than did MMCs from adults. IL-12 and IFN-gamma mRNA accumulation was examin ed by use of comparative reverse transcriptase-polymerase chain reaction. C ord blood MMCs accumulated less mRNA for both IL-12 and IFN-gamma than did adult blood MMC. The deficiency in cord blood cell production of IL-12 may have a role in inadequate IFN-gamma production, which contributes to the un ique susceptibility of neonates to GBS infections.