Decline in the production of interleukin-3 with age in mice.

Abstract Previously, we and others have found that the ability to produce interleukin-1 (IL-1) and interleukin-2 (IL-2) declines with age in mice. The purpose of this study was to determine the influence of age on the capacity of mice to produce interleukin-3 (IL-3). Splenic cells (5 × 10 6 / ml) from young (3–4 months) and old (24–32 months) C57BL/6 mice were first assessed for their IL-3-producing capacities in response to varying doses of concanavalin A (Con A; 2–20 μg/ml) in a time-dependent manner. The results showed that the production of IL-3 by both young and old C57BL/6 mice was maximal on Days 3 and 4 in response to 20 μg/ml of Con A, and that of IL-2 was minimal (activity was less than 0.1 unit) on Day 4. Consequently, Day 4 was selected to assess the effect of age on IL-3 production by splenic cells. The results showed a twofold reduction in IL-3 production with age ( P r = 0.92, P