IMPAIRED TETANUS-SPECIFIC CELLULAR AND HUMORAL RESPONSES FOLLOWING TETANUS VACCINATION IN HUMAN ONCHOCERCIASIS - A POSSIBLE ROLE FOR INTERLEUKIN-10

Onchocerca volvulus infection has been associated with impaired cellul ar responses to parasite antigens, an impairment that may also extend to nonparasite antigens, To investigate the mechanism of this impaired immune response, the effect of concurrent O. volvulus infection on th e immune response to tetanus toroid (TT) following tetanus vaccination was studied. The proliferative, cytokine, and antibody response to TT of O. volvulus-infected subjects (n = 19) and comparable noninfected controls (n = 20) were studied before and 6 months after vaccination w ith TT. Following vaccination, antibody levels, proliferative response s, and levels of interferon-gamma were significantly greater in noninf ected subjects (P < .05, .001, and .05, respectively); however, infect ed subjects produced interleukin-10, but noninfected controls did not (P = .001). These studies indicate that concurrent infection with O. v olvulus can diminish the immune response to an unrelated antigen (TT) by a mechanism that is likely to involve interleukin-10.