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Theileria parva candidate vaccine antigens recognized by immune bovine cytotoxic T lymphocytes

Graham, S.P., Pelle, R., Honda, Y., Mwangi, D.M., Tonukari, N.J., Yamage, M., Glew, E.J., De Villiers, E.P., Shah, T., Bishop, R.
Proceedings of the National Academy of Sciences of the United States of America 2006 v.103 no.9 pp. 3286-3291
cattle, cytotoxic T-lymphocytes, CD8-positive T-lymphocytes, immune response, cell-mediated immunity, antigens, Theileria parva, vaccines, vaccine development, schizonts, complementary DNA, clones, nucleotide sequences
East Coast fever, caused by the tick-borne intracellular apicomplexan parasite Theileria parva, is a highly fatal lymphoproliferative disease of cattle. The pathogenic schizont-induced lymphocyte transformation is a unique cancer-like condition that is reversible with parasite removal. Schizont-infected cell-directed CD8+ cytotoxic T lymphocytes (CTL) constitute the dominant protective bovine immune response after a single exposure to infection. However, the schizont antigens targeted by T. parva-specific CTL are undefined. Here we show the identification of five candidate vaccine antigens that are the targets of MHC class I-restricted CD8+ CTL from immune cattle. CD8+ T cell responses to these antigens were boosted in T. parva-immune cattle resolving a challenge infection and, when used to immunize naive cattle, induced CTL responses that significantly correlated with survival from a lethal parasite challenge. These data provide a basis for developing a CTL-targeted anti-East Coast fever subunit vaccine. In addition, orthologs of these antigens may be vaccine targets for other apicomplexan parasites.