title: A novel tuberculosis antigen identified from human tuberculosis granulomas.
abstract: Tuberculosis is a global infectious disease caused by Mycobacterium tuberculosis (Mtb). Although novel Mtb biomarkers from both the pathogen and host have been studied, more breakthroughs are still needed to meet different clinic requirements. In an effort to identify Mtb antigens, chaperone-peptide complexes were purified from TB infected lungs using free-solution isoelectric focusing combined with high resolution LTQ Orbitrap Velos mass spectrometry. Antigen specific cellular immune responses in vitro were then examined. Those efforts led to the identification of six Mtb peptides only identified in Tuberculosis lung samples and that were not found in the control samples. Additionally, antigen-specific IFN-γ secretion, T-cell proliferation, cytokine expression, and a cytotoxic assay were also evaluated. Among the peptides isolated, we identified a 34 amino acid peptide named PKAp belonging to a serine/threonine-protein kinase, as being able to generate Mtb-specific cellular immune responses as noted by elevated antigen-specific cytokine secretion levels, increased CD8(+) T-cell proliferation and a strong cytotoxic lymphocyte (CTL) response. Moreover, the immune stimulating abilities of PKAp were further validated in vivo, with target peptide immunized mice showing an increased cellular IFN-γ in both the lungs and spleen without causing immunopathogenesis. In conclusion, we identified novel functional Mtb antigens directly from the granulomatous lesions of Tuberculosis patients, inducing not only significant antigen-specific IFN-γ secretion but also a marked cytotoxic lymphocyte functional response. These findings indicated that PKAp has potential as a novel antigen biomarker for vaccine development.
authors.affiliation: From the ‡MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100176, China;
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: From the ‡MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100176, China;
authors.forename: Dongdong
authors.initials: D
authors.lastname: Jin
authors.affiliation: From the ‡MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100176, China;
authors.forename: Shizong
authors.initials: S
authors.lastname: Hu
authors.affiliation: From the ‡MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100176, China;
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: §Beijing Tuberculosis and Thoracic Tumor Research Institute, 101149, China;
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Zheng
authors.affiliation: From the ‡MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100176, China;
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zheng
authors.affiliation: ¶Guangdong Key Laboratory for emerging infectious diseases, Shenzhen Key Laboratory of Infection and Immunity, Shenzhen Third People's Hospital, Guangdong Medical College, Shenzhen, 518020, China;
authors.forename: Mingfeng
authors.initials: M
authors.lastname: Liao
authors.affiliation: ¶Guangdong Key Laboratory for emerging infectious diseases, Shenzhen Key Laboratory of Infection and Immunity, Shenzhen Third People's Hospital, Guangdong Medical College, Shenzhen, 518020, China;
authors.forename: Xinchun
authors.initials: X
authors.lastname: Chen
authors.affiliation: ‖Department of Neurosurgery, University of Colorado, Denver, Colorado 80045.
authors.forename: Michael
authors.initials: M
authors.lastname: Graner
authors.affiliation: From the ‡MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100176, China; haiyingbj@gmail.com.
authors.forename: Haiying
authors.initials: H
authors.lastname: Liu
authors.affiliation: From the ‡MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100176, China;
authors.forename: Qi
authors.initials: Q
authors.lastname: Jin
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D049109:Cell Proliferation; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005260:Female; D005453:Fluorescence; D006099:Granuloma / Q000276:immunology* / Q000382:microbiology; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D007114:Immunization; D007371:Interferon-gamma / Q000378:metabolism; D007525:Isoelectric Focusing; D008168:Lung / Q000378:metabolism; D008297:Male; D013058:Mass Spectrometry; D008562:Membrane Glycoproteins / Q000378:metabolism; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014376:Tuberculosis / Q000276:immunology* / Q000382:microbiology
chemical_list: D000942:Antigens, Bacterial; D018984:Epitopes, T-Lymphocyte; D018840:HSP70 Heat-Shock Proteins; D015395:Histocompatibility Antigens Class I; D008562:Membrane Glycoproteins; D010455:Peptides; C053387:endoplasmin; D007371:Interferon-gamma