In contrast with an earlier study [19], we observed a second peak of parasitemia and reduced survival in the β2-m KO, suggesting a role for CTLs in mouse resistance to P. yoelii. Similar findings were obtained in CD8-depleted mice infected with P. chabaudi AS that showed an intense reticulocytosis and two recurrent bouts of parasitemia, on day 16 (17,9%) and on day 30, (8,5%) leading to the conclusion that CD8+ T cells are important for parasite clearance [39,40]. The gene discussed is B2M; the disease is parasitic infectious disease.