| Research Abstract |
This study was conducted to uncover effects of helminth-driven immunomodulation on concurrent infections of other unrelated parasites in mice. Murine hosts infected with Schistosoma mansoni are thought to be in Th2-dominant situation, which might have detectable effects for the bio-defence system. Results in this study suggest that schistosome-driven Th2 response induced strong protective immunity against Strongyloides venezuelensis infection. On the other hand, S.mansoni infection did not have any detectable effects on Leishmania major infection for which Th1 response is hightly protective in particular mice strains. C57BL/6 mice are resistant against L.major through induction of Th1-dominant response, however, these mice were still resistant even in concomitant infection of S.mansoni. Schistosome-driven Th2 response seemed to impair killer T cell response in mice implanted with UV*1 fibrosarcoma cells. Unexpected results were observed in case of Plasmodium chabaudi infection in A/J mice, which is highly susceptible to P.chabaudi infection. When A/J mice were infected with S.mansoni, parasitemia was significantly suppressed, and moreover, no mice died of malaria, while all A/J mice infected with P.chabaudi alone died within 7 days. Together with these results, we conclude that schistosome infection could have deep effects on the bio-defence system of infected hosts, although the effects are highly heterogenous. Such effects are determined not only by host-schistosome interaction, but also by parasite-parasite interaction. The complicated mechanisms for determining the bio-defence system in infected hosts are involved in disease susceptibility of host population, and eradication of particular parasites might provide unexpected risk of another infective disease.
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