Cell mediated immunity (CMI) is suggested to be important for the protection of chickens against Leucocytozoon caulleryi. To analyze the CMI in more detail, CD4- and CD8-depleted chickens were inoculated with sporozoites of L. caulleryi and the parasitological and immunological changes were examined. CD4-depleted chickens showed a longer parasitemia than those of untreated chickens or CD8-depleted chickens at primary infection. After secondary inoculation with a lethal dose of sporozoites, CD4-depleted chickens showed increased susceptibility, whereas CD8-depleted or untreated chickens showed strong resistance. Serum-soluble antigen, which is a maker of protozoan propagation, was detected in the CD4-depleted chickens, but not in CD8- depleted or untreated chickens after the secondary infection. These results suggest that CD4+ T cells are important for the protective immunity of chickens against L. caulleryi.
(Lab. of Parasitic Diseases, Department of Bacteriology and Parasitology)
Reference:
Isobe, T., Aoki, H. and Tsuji, N. :1997. CD4+ T cell is important for protective immunity against Leucocytozoon caulleryi in chickens. Proc. of 7th Int. Coccidiosis Conf., p.94 (1997)
