T-Cell Surface Molecule Expression and Interferon-γ Production in Human Cord Blood

We investigated T-cell surface antigen expression and the production of interferon-gamma (IFN-gamma) and interleukin-2 (IL-2) by human cord and adult blood cells. Cord blood lymphocytes stimulated with Staphylococcus enterotoxin B (SEB) released only minimal titers of IFN-gamma and IL-2 in comparison with adult blood lymphocytes. Systematic analyses of several cell-surface molecules on untreated cord blood and adult blood T cells demonstrated a significant reduction of CD8+ subset numbers in cord blood. Furthermore, cord blood lymphocytes did not express the memory T-cell marker CD45RO. No differences were found in gamma/delta T-cell receptor (TCR), CD5, and CD25 antigen expression between untreated cord blood and adult blood. However, cord blood mononuclear cells showed a decreased CD25 antigen expression in comparison to those of adults following activation with SEB. These observations suggest that the decrease in the proportion of some T-cell subsets and the absence of CD45RO memory T cells may be responsible for the diminished lymphokine production of cord blood lymphocytes.