Deficient tumor necrosis factor secretion by cord blood mononuclear cells upon in vitro stimulation with Listeria monocytogenes

We examined the production of tumor necrosis factor (TNF) by mononuclear cells (MNC) after incubating adult or cord blood MNC with Listeria monocytogenes in vitro, With adult MNC cultures, we found that TNF activity reached a peak at 6 h (606 +/- 120 x 10(3) units/liter) and declined to the baseline by day 3. In contrast, using cord blood MNC, we found that TNF activity increased gradually reaching a peak at 24 h, In addition, the peak TNF activity using newborn MNC (189 +/- 26 x 10(3) U/liter) at 24 h was still lower than the peak using adult MNC at 6 h (p < 0.0002). In seeking an explanation for the decreased TNF secretion from newborn MNC, we examined the possibility that newborn cells produce TNF but failed to secrete it. However, lysates of newborn cells contained functionally and antigenically less TNF than adult cells, Based on these observations, we conclude that the overall TNF production by newborn cells incubated with L. monocytogenes is decreased compared with similarly stimulated adult cells.