Mycobacterium tuberculosis-specific and MHC class I-restricted CD8+ T-cells exhibit a stem cell precursor-like phenotype in patients with active pulmonary tuberculosis

• Published in: International journal of infectious diseases Vol. 32; no. C; pp. 13 - 22
• Main Authors: Axelsson-Robertson, Rebecca, Ju, Ji Hyeon, Kim, Ho-Youn, Zumla, Alimuddin, Maeurer, Markus
• Format: Journal Article
• Language: English
• Published: Canada Elsevier Ltd 01.03.2015; Elsevier
• Subjects: Adult; Aged; Antigens, Bacterial - immunology; CD8+ T-cells; CD8-Positive T-Lymphocytes - immunology; Cytokines - metabolism; Epitopes, T-Lymphocyte; Female; Histocompatibility Antigens Class I - metabolism; Humans; Infectious Disease; Male; Middle Aged; Mycobacterium tuberculosis; Mycobacterium tuberculosis - immunology; Phenotype; Pulmonary/Respiratory; Stem Cells - immunology; T-cell differentiation; Tetramer; Tuberculosis, Pulmonary - immunology; Young Adult; T-cell differentiation; Mycobacterium tuberculosis; CD8+ T-cells; Tetramer
• ISSN: 1201-9712; 1878-3511
• DOI: 10.1016/j.ijid.2014.12.017

•Mycobacterium tuberculosis (MTB) antigen-specific CD8+ T-cells exhibited a distinct marker profile associated with the nature of the MTB antigens, i.e. Rv0288, Rv1886c, and Rv3875-reactive T-cells clustered in the precursor T-cell compartment, whereas Rv2958c, Rv2957, and Rv0447c-reactive T-cells were associated with the terminally differentiated T-cell phenotype, in the patient cohort. MTB-specific T-cells in patients with active TB are more frequently directed against a particular set of antigens derived from ‘early secreted antigens’ and not against antigens expressed by slow-growing bacteria.•Rv0288, Rv1886c, and Rv3875-specific CD8+ T-cells were significantly enriched for CD107a+ T-cells in HLA-A*02:01 (p<0.0001) and HLA-A*24:02 (p=0.0018) positive individuals, as compared to Rv2958c, Rv2957, and Rv0447c antigens. CD127 (interleukin 7 receptor (IL-7R))-expressing T-cells were enriched in HLA-A*02:01-positive individuals for the Rv0288, Rv1886c, and Rv3875 specificities (p=0.03).•A high proportion of antigen-specific T-cells showed a precursor-like phenotype (CD45RA+CCR7+) and expressed the stem cell-associated markers CD95 and c-kit. The data show that MTB-specific T-cells can express stem cell-like features; this is associated with the nature of the MTB antigen and the genetic background of the individual.•The data imply that we may underestimate the number of antigen-specific T-cells in patients with active TB, shown by higher numbers of tetramer-reactive T-cells as compared to interleukin 2, interferon, tumour necrosis factor, or interleukin 17 production in the same blood sample. The nature and longevity of the T-cell response directed against Mycobacterium tuberculosis (MTB) are important for effective pathogen containment. We analyzed ex vivo the nature of MTB antigen-specific T-cell responses directed against the MTB secreted antigens Rv0288, Rv1886c, Rv3875, the antigens Rv2958c, Rv2957, and Rv0447c (intracellular, non-secreted enzymes) in blood from Korean patients with active tuberculosis (TB). MTB-specific T-cell function was defined by intracellular cytokine production (interleukin (IL)-2, interferon gamma, tumour necrosis factor alpha, and IL-17) and by multimer-guided (HLA-A*02:01 and HLA-A*24:02) analysis of epitope-specific CD8+ T-cells, along with phenotypic markers (CD45RA and CCR7), CD107a, a marker for degranulation, and CD127 co-staining for T-cell differentiation and homing. Cytokine production analysis underestimated the frequencies of MTB antigen-specific T-cells defined by major histocompatibility complex (MHC) class I–peptide multimer analysis. We showed that MTB antigen-specific CD8+ T-cells exhibit a distinct marker profile associated with the nature of the MTB antigens, i.e., Rv0288, Rv1886c, and Rv3875-reactive T-cells clustered in the precursor T-cell compartment, whereas Rv2958c, Rv2957, and Rv0447c-reactive T-cells were associated with the terminally differentiated T-cell phenotype, in the patient cohort. Rv0288, Rv1886c, and Rv3875-specific CD8+ T-cells were significantly enriched for CD107a+ T-cells in HLA-A*02:01 (p<0.0001) and HLA-A*24:02 (p=0.0018) positive individuals, as compared to Rv2958c, Rv2957, and Rv0447c antigens. CD127 (IL-7 receptor)-expressing T-cells were enriched in HLA-A*02:01-positive individuals for the Rv0288, Rv1886c, and Rv3875 specificities (p=0.03). A high proportion of antigen-specific T-cells showed a precursor-like phenotype (CD45RA+CCR7+) and expressed the stem cell-associated markers CD95 and c-kit. These data show that MTB-specific T-cells can express stem cell-like features; this is associated with the nature of the MTB antigen and the genetic background of the individual.