Immunity and Vaccine Development in the Bovine Theilerioses

摘要: There are three economically important bovine Theileria species: annulata, which causes tropical theileriosis and occurs across north Africa most of central Asia; parva, East Coast fever is found in Central Africa; sergenti, predominantly a problem Japan Korea. annulata preferentially infects macrophages vivo. It controlled largely by means live, attenuated vaccines, produced prolonged tissue culture the schizont-infected cells. The immunity induced animals, have either recovered from an infection or been vaccinated (with vaccine), broad, solid cell mediated. considered that main effector cells cytostatic produce nitric oxide. Subsidiary roles for leucocyte antigen (BoLA)-restricted, transiently appearing, cytotoxic T cells, possibly also natural killer (NK) identified. Cytokines such as tumour necrosis factor alpha (TNF-alpha) may roles, particularly induction pathology. Matrix metalloproteinases implicated metastatic behaviour nature protective schizont target antigens remains unknown. Attempts to develop subunit vaccine focused upon sporozoite (SPAG-1) merozoite (Tams1). Both SPAG-1 Tams1 given partial protection using different delivery systems adjuvants, but further development will probably require identification range other antigens, especially stage. parva has tropism Vaccination currently 'infection treatment' method, involves challenging with dose stabilate simultaneous administration long-acting tetracyclines. thus mediated BoLA-restricted recognize polymorphic antigens. These not characterized at molecular level. However, underlies fact very strain specific--a situation distinguishes T. annulata. Interestingly, it possible requires up two orders magnitude more schizonts order achieve transfer new host. A suggested reason this macrophage targets phagocytes natural, efficient route entry whilst preferred host non-phagocytic cell. Analysis T-cell response revealed evidence BoLA haplotype dominance plus competition between parasite epitopes. Subunit vaccination recombinant (p67) proved promising, levels 70% being achieved. proportion protected calves exhibits complete sterile immunity. basis clear, since there no correlation titre antibodies inhibit penetration lymphocytes protection. Similarly, significant susceptible animals. data encouraging, components, those derived schizont, need be identified characterized. mild species Korea (termed sergenti literature) cause severe chronic anaemia. stage life cycle rare type known. pathology associated piroplasm infection. Immunity can immunizing crude extracts. Serological analysis immune sera reveals immunodominant polypeptide 30-33 kDa, corresponds Tams1. (ABSTRACT