Melatonin restores immunodepression in aged and cyclophosphamide-treated mice.

Melatonin, the main hormone of the pineal gland, when chronically injected into young mice or mice immunodepressed by aging or by cyclophosphamide treatment, was able to enhance the antibody response to a T-dependent antigen. The enhancement of antibody response was associated with increased induction of T helper cell activity and IL-2 production as evidenced in mice immunodepressed by aging or by cyclophosphamide treatment. These observations suggest that melatonin may be successfully used in the therapy of immunodepressive conditions.