Polymorphism of human T cell epitopes of eight immune-related conserved hypothetical proteins in Mycobacterium tuberculosis

Objective To investigate the polymorphisms of human T epitopes of antigens Rv1158c, Rv1461, Rv1977, Rv2182c, Rv3207c, Rv-3333c, Rv3378c and Rv3714c in Mycobacterium (M.) tuberculosis isolated in China. Methods We selected 151 clinical isolates of M. tuberculosis for the amplification of gene sequences of the eight antigens. The sequence alignment was conducted with software Bioedit. Results Among the 151M. tuberculosis strains, all the proteins were conservative in T cell epitopes except Rv1977. There were three non-synonymous mutations and one frame shift mutation in Rv1977. The mutations and deletion in Rv1977 all affected one of three T cell epitopes. Conclusion Among 8 immune-related conserved hypotheticals proteins in M. tuberculosis, only Rv1977 showed polymorphism in T cell epitopes, indicating that the antigen might be involved in diversifying selection to evade host immunity.