title: Genetic diversity of antigens Rv2945c and Rv0309 in Mycobacterium tuberculosis strains may reflect ongoing immune evasion.
abstract: Host immune pressure and associated immune evasion of pathogenic bacteria are key features of host-pathogen co-evolution. A previous study showed that human T-cell epitopes of Mycobacterium tuberculosis are evolutionarily hyperconserved and thus it was deduced that M. tuberculosis lacks antigenic variation and immune evasion. Here, we selected 173 clinical M. tuberculosis complex (MTBC) isolates from China, amplified the genes encoding Rv2945c and Rv0309, and compared the sequences. The results showed that genetic diversity existed in these two genes among the MTBC strains and two single nucleotide polymorphisms (SNPs) presented higher polymorphisms. Antigen Rv2945c harbored a higher number of amino acid substitutions of its T-cell epitopes, which may reflect ongoing immune evasion. In addition, the high dN/dS value of Rv0309 suggested antigen Rv0309 might be involved in diversifying selection to evade host immunity. Finally, a small group of strains were identified based on the genetic diversity of these two genes, which might indicate that they interact differently with human T cells compared with other strains.
authors.affiliation: National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention/State Key Laboratory for Infectious Disease Prevention and Control, Beijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Jiang
authors.forename: Xiangfeng
authors.initials: X
authors.lastname: Dou
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.forename: Haican
authors.initials: H
authors.lastname: Liu
authors.forename: Xiuqin
authors.initials: X
authors.lastname: Zhao
authors.forename: Haiyin
authors.initials: H
authors.lastname: Wang
authors.forename: Lulu
authors.initials: L
authors.lastname: Lian
authors.forename: Qin
authors.initials: Q
authors.lastname: Yu
authors.forename: Jingrui
authors.initials: J
authors.lastname: Zhang
authors.forename: Guilian
authors.initials: G
authors.lastname: Li
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.forename: Kanglin
authors.initials: K
authors.lastname: Wan
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D018984:Epitopes, T-Lymphocyte / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D014376:Tuberculosis / Q000382:microbiology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D018984:Epitopes, T-Lymphocyte
keywords: Mycobacterium tuberculosis; T-cell epitopes; host-pathogen co-evolution