The effect of chloroquine on the production of interferon-gamma, interleukin (IL)-4, IL-6, and IL-10 in Plasmodium chabaudi chabaudi in infected C57BL6 mice

The effect of chloroquine (CQ) on the production pattern of interferon (IFN )-gamma, interleukin (IL)-4, IL-6, and IL-10 in female C57BL6 mice infected with Plasmodium chabaudi chabaudi AS was evaluated during a period of 35 c lays. Our data confirm that there is a switch from a T helper cell (Th)1 to a Th2 response during malaria infection in this model. Proliferation assay s showed a decreased stimulation index in infected mice that was further re duced in infected mice treated with CQ, Noninfected control mice treated wi th CQ showed an increase production of IFN-gamma. However, no detectable ch anges in IL-4, IL-6, and IL-10 production were observed in this group. CQ t reatment of infected mice resulted in parasite clearance that was associate d with an earlier production of IL-4, IL-6, and IL-IO when compared with no ntreated infected mice. We suggest that this earlier switch to a Th2 respon se is a consequence of parasite killing rather than CQ interference with cy tokine production.