The effect of cold stress on lymphocyte proliferation in fetal ethanol-exposed rats

Prenatal ethanol exposure and stress have each been shown to have significant effects on the immune system. This study examined the possible interactive effects of prenatal ethanol exposure and exposure to stress later in life on the immune system. Differential vulnerability to these challenges in female and male offspring was assessed. At 5 to 6 months of age, female and male offspring from prenatal ethanol-exposed (E), pair-red (PF), and ad libitum-fed control (C) conditions were exposed to 0, 1 or 3 days of cold (4 degrees C). At the end of the cold period, the proliferative response of splenic lymphocytes to the mitogens concanavalin A (Con A) and pokeweed mitogen (PWM) was assessed. The data demonstrate a significant interactive effect between prenatal ethanol exposure and cold stress in female offspring. After 1 day of cold stress, E females had significantly increased PWM-induced lymphocyte proliferation compared with PF and C females, and significantly increased Con A-induced lymphocyte proliferation compared with PF females. There were no differences in PWM or Con A-induced lymphocyte proliferation among E, PF, and C females after 0 or 3 days of cold stress, nor among E, PF, and C males on any test day. Regardless of prenatal treatment, females exposed to 1 or 3 days of cold had significantly greater basal plasma corticosterone levels than females not exposed to cold. In contrast, only E males exposed to 1 or 3 days of cold had significantly increased basal plasma corticosterone levels, compared with E males not exposed to cold; PF and C males showed no significant change in basal corticosterone after cold stress. These data demonstrate that, in response to the challenge of cold stress, changes in lymphocyte proliferation to PWM and Con A may occur selectively in E females. Moreover, the interactive effects of prenatal ethanol and cold stress may result in enhanced rather than suppressed immune responsiveness.