DEFECTIVE CYTOKINE EXPRESSION BUT ADULT-TYPE T-CELL RECEPTOR, CD8, AND P56(LCK) MODULATION IN CD3-ACTIVATED OR CD2-ACTIVATED T-CELLS FROM NEONATES

Expression of IL-2, interferon-gamma, and IL-3 mRNA and proteins was i nvestigated in peripheral blood mononuclear cells from cord blood afte r activation with phytohemagglutinin, CD2, or CD3 MAb. The results sho wed that interferon-gamma and IL-3 expression was decreased in cord pe ripheral blood mononuclear cells when compared with expression observe d in adult peripheral blood mononuclear cells, irrespective of the sti mulation used. In addition, in newborn cells a defect in IL-2 secretio n and mRNA expression was observed in response to CD2 or CD3 MAb, but not in response to phytohemagglutinin-mediated activation. We further analyzed the modulation of nonlymphokine genes under the same protocol of stimulations. The results indicate that in newborn cells, despite a reduced lymphokine expression observed after CD2 or CD3 MAb activati on, the up-regulation of the T-cell receptor, CD8, and p56(lck) was si milar to that found in adult cells, as was also found after phytohemag glutinin activation of both types of cells. These data are in favor of a deficient T-cell responsiveness to CD2 or CD3 MAb, in newborn cells . This impairment of the T-cell response appears to selectively affect lymphokine gene expression because the modulation of other genes also implicated in T cell activation is not altered.