RELEASE OF IL-1 AND IL-2 AND EXPRESSION OF IL-2 RECEPTORS AS A FUNCTION OF POSTNATAL AGE AND SEX

Release patterns of the mitogen-induced cytokines IL-1 and IL2 by Long Evans rat unfractionated spleen cells, as well as expression of IL-2R on such cells at different postnatal days (neonatal to adult) were st udied for female and male rats. IL-1 release was found to be low but i n a more or less steady fashion in cells of both sexes over the entire period. However, IL-2 synthesis increased from an almost undetectable level up to a significant secretion at the time of weaning and contin ued to increase in female but not male spleen cells. IL-2 receptors we re found to be expressed in moderate amounts already at early postnata l days and up to weaning. Thereafter, the synthesis of IL-2R followed a course essentially similar to that of IL-2, i.e. higher for female t han for male cells. In the female rats, a hormonal influence was obser ved on the formation of IL-1 and IL-2 but not on the expression of IL- 2R.