β-Endorphin effects on antibody production, proliferation, and secretion of Th1/Th2 cytokines in vivo.

Intraperitoneal injection of β-endorphin in doses of 1, 0.01, and 0.0005 μg/kg under conditions of systemic immunization increased the count of antibody-producing cells in the spleen and the titer of anti-erythrocyte antibodies in the plasma of experimental animals. Intraperitoneal β-endorphin stimulated proliferative activity of splenocytes in mice in the presence of both B- and T-cell mitogen, did not change the production of IFN-γ, reduced the level of IL-2, and stimulated the secretion of IL-4, the main Th2-polarizing factor.