To evaluate whether IL-2 is required to induce and to sustain the suppressive activity of Treg cells in malaria, we examined in detail the effects of anti-IL-2 treatment with JES6-1 monoclonal antibody (mAb) on the splenic CD4+ T cell response during acute and chronic P. chabaudi AS infection in C57BL/6 mice. The gene discussed is IL2; the disease is malaria.