Comparison of antibody responses against Mycobacterium tuberculosis antigen Rv0679c in tuberculosis patients from the endemic and non-endemic regions of the Beijing genotype: a case control study

• Published in: BMC infectious diseases 2017-05, Vol.17 (1), p.344-344, Article 344
• Main Authors: Zhao, Jingge, Matsuba, Takashi, Zhang, Xiaoyan, Leano, Susan, Nakajima, Chie, Chagan-Yasutan, Haorile, Telan, Elizabeth Freda, Suzuki, Yasuhiko, Hattori, Toshio
• Format: Article
• Language: English
• Subjects: Amino acids; Animals; Antibodies, Monoclonal - immunology; Antibody Formation; Antigenicity; Antigens; Antigens, Bacterial - genetics; Antigens, Bacterial - immunology; Bacteria; Beijing; Beijing genotype; Case-Control Studies; China - epidemiology; Cytokines; Dimorphic antigen; Enzymes; Epitopes; Genotype; Health care; Hospitals; Humans; Immune response; Immune system; Immunoglobulin A - blood; Immunoglobulin G; Immunoglobulin G - blood; Immunoglobulins; Immunology; Infections; Lung diseases; Membrane proteins; Mice; Mutation; Mycobacterium tuberculosis; Mycobacterium tuberculosis - genetics; Mycobacterium tuberculosis - immunology; Pandemics; Patients; Peptides; Philippines; Polyclonal antibodies; Proteins; Rv0679c; Tuberculosis; Tuberculosis - epidemiology; Tuberculosis - immunology; Tuberculosis, Pulmonary - immunology; Virulence
• ISSN: 1471-2334; 1471-2334
• DOI: 10.1186/s12879-017-2442-5

Strains of the Beijing genotype of Mycobacterium tuberculosis (MTB) are reportedly associated with the virulence of tuberculosis (TB) infection, unfavorable outcomes of anti-TB treatment, and the global TB pandemic. Rv0679c, a hypothetical membrane protein related to host cell invasion, has a Beijing genotype-specific mutation at residue 142 (Asn142Lys). Antigenicity differences between Rv0679c-Asn142 (N-type) and Rv0679c-Lys142 (K-type) have been previously observed in mice antigen-antibody responses. However, the immune response to Rv0679c in humans remains unknown. Therefore, we aimed to investigate the anti-Rv0679c immune response in TB patients from the endemic and non-endemic regions of the Beijing MTB genotype. We analyzed the Rv0679c-specific antibody responses in 84 subjects from the endemic region of the Beijing genotype MTB in China, including 45 pulmonary TB patients (C-PTB) and 39 healthy controls (C-HC), and 81 subjects from the Philippines (the endemic region of the non-Beijing genotype), including 51 pulmonary TB patients (P-PTB) and 30 healthy controls (P-HC). Anti-tuberculous-glycolipid (TBGL) antigen was used as the control antibody. TBGL IgG titers were higher in both C-PTB and P-PTB than those in their corresponding HC (C-PTB median 4.2, P-PTB median 11.2; C-PTB vs. P-PTB, p > 0.05), suggesting immune response comparability in PTB from two different countries. C-PTB showed a higher response compared to C-HC for anti-K-type IgG (53.3%) than anti-N-type IgG (6.67%); this response was not observed in P-PTB (both N-type and K-type 9.80%). Dimorphic antigen Rv0679c was found to be associated with distinct immune response patterns, indicating the role of Beijing/non-Beijing genotype of MTB in stimulating specific responses in TB patients from the endemic region of Beijing MTB. Meanwhile, reactions to Rv0679c in patients and HC from non-endemic regions of the Beijing MTB may be caused by the response to the common epitope of Rv0679c N/K-type.