Interleukin-1 augments the diminished interleukin-2 mRNA expression and proliferative response of neonatal T lymphocytes to anti-CD2 antibodies.

Expression of IL-2 mRNA by unstimulated and stimulated purified T cells and mononuclear cells from adult and cord blood was investigated in an attempt to better understand the underlying defective neonatal host immune defense system. Using RNA dot-blot analysis, IL-2 mRNA expression in anti-CD2-stimulated neonatal T cells revealed significantly reduced levels when compared to adult T cells (P < 0.01). Purified neonatal T cells also showed a significantly reduced proliferative response to anti-CD2 antibodies (P < 0.01). Addition of IL-1 beta enhanced the hyporesponsiveness of neonatal T cells at both the level of proliferation and IL-2 mRNA expression. Unseparated mononuclear cells from adult and cord blood revealed similar IL-2 mRNA levels and proliferation when activated by anti-CD2 stimulation. The reduced IL-2 mRNA expression observed in neonatal T cells may explain, in part, the difference in host defense between the newborn and adult during states of increased demand such as infection.