PDCD1 and parasitic infectious disease: However, although P. chabaudi infection in mice has a prolonged acute parasitemia and a long chronic phase, few PD-1+ effector (Figure 2E) Tg CD4+ T cells (all CD62Llo, maximum of 5.7% at day 21) were transiently present, and no KLRG-1+ cells were observed (data not shown).