CD4 and parasitic infectious disease: It should be noted, however, that in our experiments JES6-1 treatment results in substantial CD4+ T cell activation in non-infected mice, whereas IL-2/JES6-1 treatment leads to expansion of the Treg cell population and, in consequence, to reduction of CD4+ and CD8+ T cell responses to Plasmodium berghei infection [24] and to increase in parasitemia during P. chabaudi infection [27].