IMPAIRMENT OF TETANUS TOXOID-SPECIFIC TH1-LIKE IMMUNE-RESPONSES IN HUMANS INFECTED WITH SCHISTOSOMA-MANSONI

After vaccination with tetanus toroid (TT), TT-specific immune respons es in humans infected with Schistosoma mansoni were assessed. Peripher al blood mononuclear cells (PBMC) from vaccinated infected subjects an d vaccinated uninfected controls were evaluated for their ability to p roduce cytokines characteristic of Th1 or Th2 cells (interferon [IFN]- gamma or interleukin [IL]-4, respectively) after in vitro restimulatio n with TT. TT-specific IFN-gamma production by PBMC from infected subj ects was inversely related to infection intensity and was significantl y lower than TT-specific IFN-gamma production by control PBMC. PBMC fr om all of the infected subjects and 3 of the 5 controls analyzed by re verse transcriptase-polymerase chain reaction transcribed the IL-4 gen e in response to TT restimulation. Together, these results suggest tha t S. mansoni-infected persons mount a Th2-like response to the bystand er antigen TT, while uninfected persons mount a Th1- or Th0-like respo nse.