Humoral immune response suppresses reproductive physiology in male Brandt's voles (Lasiopodomys brandtii).

In order to evaluate the potential costs of humoral immune response, which is important for survival in small wild mammals, we studied the physiological function of adult male Brandt's voles (Lasiopodomys brandtii) challenged with human immunoglobulin G (IgG). Compared with controls, the immunochallenged voles showed significantly higher antibody levels 15 days after injection. Serum testosterone levels, and mass of testes and epididymides were lower in immunochallenged voles than in control animals.