Melatonin improves humoral and cell-mediated immune responses of male golden hamster following stress induced by dexamethasone

•Mel improved the dex-induced immunosuppression of splenocytes & GM-CFU count.•Mel antagonized the dex-induced inhibition of IL-2 and anti-KLH IgG production.•Mel increased the expression of receptor MT1 and decreased GR expression.

Melatonin is known as an antistress and immunostimulator compound while glucocorticoids have immunosuppressive function. The mechanism of action of both the hormones on immune cells is still a question. We found that melatonin improved the effect of dexamethasone (synthetic glucocorticoid) induced immunosuppression of splenocytes and bone marrow GM-CFU along with increased production of serum IL-2, IgG and the receptor expression for melatonin and glucocorticoid in spleen that might be responsible for the proliferation of immune cells. Thus, seasonal variation in peripheral melatonin might be responsible for the improvement of immune status under different stress conditions experienced by the rodents for better survival.