Bovine T-cell responses to defined Trypanosoma congolense antigens during infection
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Permanent link to this item: http://hdl.handle.net/10568/2826
Internet URL: https://cgspace.cgiar.org/handle/10568/2726
Infections of cattle with tsetse-transmitted Trypanosoma congolense are accompanied by antibody responses to the variable surface glycoprotein (VSG) and to two major invariant antigens, a member of the hsp 70 family and a 33KDa cysteine protease. During primary infection, trypanotolerant N'Dama (Bos taurus) cattle exhibit higher levels of IgG1 to CP than susceptible Borans. Boran cattle, on the other hand, have high levels of IgM to irrelevant antigens. During rechallenge infections, N'Dama cattle have higher levels of IgG1 to hsp70 while Boran cattle exhibit high titres of IgM to this antigen. Although Boran cattle do generate high titres of IgM to hsp70, N'Dama cattle develop higher levels of specific IgG antibody (Authie et al., 1993b). These observations are consistent with a possible dysfunction in isotype switch from IgM to IgG in Boran cattle. Because of the central role of T helper cells in induction of Ig isotype switch, the difference in antibody responses between N'Dama and Boran cattle migh reflect defective T helper cell function in the susceptible breeds during infection. We undertook a study to analyse T-cell function in cattle during infection with T. congolense. T-cell proliferative responses to a recombinant form of the hsp70 (R63), cysteine protease and VSG were measured in a group of Boran cattle following primary challenge with T. congolense. The role of CD4+ and CD8+ cells in the response was also investigated.