Immunodepression during Trypanosoma brucei gambiense infections in the field vole, Microtus montanus.

The effects of Trypanosoma brucei gambiense infections upon immune responses were examined in an outbred laboratory colony of field voles. Microtus montanus. Antibody levels to challenge with heterologous erythrocytes and bovine serum albumin were significantly depressed in infected animals. Trypanosome infections impaired both primary and secondary humoral responses, although previously established specific antibody levels were not affected by infection. Specific antibody-producing capabilities of previously infected, trypanoicidal drug-treated voles were found to be comparable to uninfected controls, within 3 days following chemotherapy. Cell-mediated hypersensitivity responses to oxazolone were also significantly depressed by trypanosome infection; responses to the initial sensitization of oxazolone and to secondary challenge treatments were depressed compared to uninfected controls. Possible mechanisms of trypanosome-induced immunodepression are discussed.