Interleukin-2 production by human fetal lymphocytes.

ABSTRACT

IL-2 production by PHA-stimulated human lymphocytes in umbilical blood was studied ontogenetically. Lymphocytes from the 16-week-old fetus produced appreciable amounts of interleukin-2 (IL-2). In 16- to 36-week-old fetuses the IL-2 production rate was found to be significantly higher than that in adults. When signal transduction, which is mediated by high affinity IL-2 receptors (IL-2R), was studied after adding exogenous IL-2 to PHA-blast lymphocytes, the response of the 24-week-old fetus was similar to that of adults. These results indicate that the attainment of IL-2 production and the function of IL-2 receptors are completed at a relatively early stage of fetal development.