Cocaine-induced suppression of interferon-gamma secretion in leukocytes from young and old C57BL/6 mice

The effects of cocaine (0.1-100 micrograms/ml) were studied on interferon-gamma (IFN) secretion in Con A-stimulated splenocytes from young (4 months) and old (18 months) C57BL/6 mice. IFN secretion was significantly suppressed by cocaine in a concentration-dependent manner. Suppression was observed in splenocytes from both young and old mice. Splenocytes from young mice released higher amounts of IFN (23.40 +/- 1.47 ng/ml) than those from old mice (6.10 +/- 0.35 ng/ml) after 24 h in culture. The concentration of Con A used to stimulate IFN secretion significantly affected the suppressive effect of cocaine. Pretreatment of splenocytes with cocaine followed by culture in the absence of cocaine did not affect IFN secretion in old mice, while splenocytes from young mice showed a sustained depression in IFN release. This suggests that cocaine suppresses IFN release in vitro and the susceptibility to this inhibitory effect may be age related.