Pharmacological and biochemical studies on the role of free radicals during stress-induced immunomodulation in rats

► Restraint stress suppressed markers of humoral and cell mediated immunity in rats. ► Such stress induced immunomodulation was accompanied by elevated malondialdehyde and lowered antioxidant levels. ► Pretreatment with antioxidants, attenuated stress induced changes in immunological and oxidative markers. ► Oxidative stress may be involved in such stress induced immunomodulation.