Immunoproteomic identification of human T cell antigens of Mycobacterium tuberculosis that differentiate healthy contacts from tuberculosis patients.
Identification of Mycobacterium tuberculosis antigens inducing cellular immune responses is required to improve the diagnosis of and vaccine development against tuberculosis. To identify the antigens of M. tuberculosis that differentiated between tuberculosis (TB) patients and healthy contacts based on T cell reactivity, the culture filtrate of in vitro grown M. tuberculosis was fractionated by two-dimensional liquid phase electrophoresis and tested for the ability to stimulate T cells in a whole blood assay. This approach separated the culture filtrate into 350 fractions with sufficient protein quantity (at least 200 microg of protein) for mass spectrometry and immunological analyses. High levels of interferon-gamma (IFN-gamma) secretion were induced by 105 fractions in healthy contacts compared with TB patients (p < 0.05). Most interesting was the identification of 10 fractions that specifically induced strong IFN-gamma production in the healthy contact population but not in TB patients. Other immunological measurements showed 42 fractions that induced significant lymphocyte proliferative responses in the healthy contact group compared with the TB patients. The tumor necrosis factor-alpha response for most of the fractions did not significantly differ in the tested groups, and the interleukin-4 response was below the detectable range for all fractions and both study groups. Proteomic characterization of the 105 fractions that induced a significant IFN-gamma response in the healthy contacts compared with the TB patients led to the identification of 59 proteins of which 24 represented potentially novel T cell antigens. Likewise, the protein identification in the 10 healthy "contact-specific fractions" revealed 16 proteins that are key candidates as vaccine or diagnostic targets.
Deenadayalan
Anbarasu
A
Tuberculosis Research Centre, Indian Council of Medical Research, Mayor V. R. Ramanathan Road, Chetput, Chennai 600 031, India.
Heaslip
Darragh
D
Rajendiran
Adhilakshmi Aavudaiyappan
AA
Velayudham
Banurekha Vaithilingam
BV
Frederick
Sheela
S
Yang
Hong-Liang
HL
Dobos
Karen
K
Belisle
John T
JT
Raja
Alamelu
A
D000328:Adult; D000942:Antigens, Bacterial / Q000032:analysis* / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D007159:Immunologic Tests; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism; D015847:Interleukin-4 / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000737:chemistry* / Q000276:immunology; D040901:Proteomics; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D014397:Tuberculosis, Pulmonary / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
D000942:Antigens, Bacterial; D014409:Tumor Necrosis Factor-alpha; D015847:Interleukin-4; D007371:Interferon-gamma