title: Foxp3+ regulatory T cells among tuberculosis patients: impact on prognosis and restoration of antigen specific IFN-γ producing T cells.
abstract: CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg) and programmed death-1 (PD-1) molecules have emerged as pivotal players in immune suppression of chronic diseases. However, their impact on the disease severity, therapeutic response and restoration of immune response in human tuberculosis remains unclear. Here, we describe the possible role of Treg cells, their M. tuberculosis driven expansion and contribution of PD-1 pathway to the suppressive function of Treg cells among pulmonary tuberculosis (PTB) patients. Multicolor flow cytometry, cell culture, cells sorting and ELISA were employed to execute the study. Our results showed significant increase in frequency of antigen-reactive Treg cells, which gradually declined during successful therapy and paralleled with decline of M. tuberculosis-specific IL-10 along with elevation of IFN-γ production, and raising the IFN-γ/IL-4 ratio. Interestingly, persistence of Treg cells tightly correlated with MDR tuberculosis. Also, we show that blocking PD-1/PD-L1 pathway abrogates Treg-mediated suppression, suggesting that the PD-1/PD-L1 pathway is required for Treg-mediated suppression of the antigen-specific T cells. Treg cells possibly play a role in dampening the effector immune response and abrogating PD-1 pathway on Treg cells significantly rescued protective T cell response, suggesting its importance in immune restoration among tuberculosis patients.
authors.affiliation: Cellular Immunology Division, Department of T.I.I., All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India.
authors.forename: Amar
authors.initials: A
authors.lastname: Singh
authors.forename: Aparajita Ballave
authors.initials: AB
authors.lastname: Dey
authors.forename: Anant
authors.initials: A
authors.lastname: Mohan
authors.forename: Prabhat Kumar
authors.initials: PK
authors.lastname: Sharma
authors.forename: Dipendra Kumar
authors.initials: DK
authors.lastname: Mitra
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D015847:Interleukin-4 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D061026:Programmed Cell Death 1 Receptor / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism*; D014397:Tuberculosis, Pulmonary / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D055815:Young Adult
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor; D015847:Interleukin-4; D007371:Interferon-gamma