CHARACTERIZATION OF T-CELL IMMUNE-RESPONSES OF ECHINOCOCCUS MULTILOCULARIS-INFECTED C57BL 6J MICE/

Specific and non-specific parasite-induced changes in lymphocyte respo nses were analysed in C57BL/6J mice after intrahepatic infection with Echinococcus multilocularis. Spleen cells harvested at selected times after infection were in vitro stimulated with mitogens or a crude solu ble parasitic extract (EmAg) at an optimized dose. Cell proliferative responses to Con-A were not modified by the infection over the first 2 2 week. In contrast, LPS-induced responses were decreased from the 13t h week. A strong CD4(+) proliferative T-cell response to the parasitic extract of infected mouse spleen cells was observed at the early stag e of infection. This response then progressively decreased but remaine d significantly, higher than that of control mice until the 19th week of infection. Cytokine production was investigated after in vitro EmAg stimulation of spleen cells. IFN-gamma, IL-2, IL-5 were produced with in the first weeks after infection whereas the detection of IL-10 was slightly delayed. Thus, the promotion of the disease does not appear a ssociated with the expansion of one rather than another T-cell subset in C57BL/6J mice. A general immunosuppression affecting both mitogenic and parasite-specific T-cell responses was observed at the end of the infection.