Identification of Mycobacterium tuberculosis-Specific Th1, Th17 and Th22 Cells Using the Expression of CD40L in Tuberculous Pleurisy

Abstract

Important advances have been made in the immunodiagnosis of tuberculosis (TB) based on the detection of Mycobacterium tuberculosis (MTB)-specific T cells. However, the sensitivity and specificity of the immunological approach are relatively low because there are no specific markers for antigen-specific Th cells, and some of the Th cells that do not produce cytokines can be overlooked using this approach. In this study, we found that MTB-specific peptides of ESAT-6/CFP-10 can stimulate the expression of CD40L specifically in CD4+ T cells but not other cells from pleural fluid cells (PFCs) in patients with tuberculous pleurisy (TBP). CD4+CD40L+ but not CD4+CD40L− T cells express IFN-γ, IL-2, TNF-α, IL-17 or IL-22 after stimulation with MTB-specific peptides. In addition, CD4+CD40L+ T cells were found to be mostly polyfunctional T cells that simultaneously produce IFN-γ, IL-2 and TNF-α and display an effector or effector memory phenotype (CD45RA−CD45RO+CCR7−CD62L−ICOS−). To determine the specificity of CD4+CD40L+ T cells, we incubated PFCs with ESTA-6/CFP-10 peptides and sorted live CD4+CD40L+ and CD4+CD40L− T cells by flow cytometry. We further demonstrated that sorted CD4+CD40L+, but not CD4+CD40L− fractions, principally produced IFN-γ, IL-2, TNF-α, IL-17 and IL-22 following restimulation with ESTA-6/CFP-10 peptides. Taken together, our data indicate that the expression of CD40L on MTB-specific CD4+ T cells could be a good marker for the evaluation and isolation of MTB-specific Th cells and might also be useful in the diagnosis of TB.

Expansion of Pathogen-Specific Mono- and Multifunctional Th1 and Th17 Cells in Multi-Focal Tuberculous Lymphadenitis

“…Similarly, a subset of CD4 + T cells that expresses IL-22 (distinct from Th17 cells) is also thought to play an important role in immunity to human TB infection [17], [27]. In addition, CD4 + T cells expressing different combinations of IFN-γ, IL-2, TNF-α, IL-17A, and IL-22 have been described in tuberculous pleurisy [38], [39]. Finally, a recent study has reported that the CD4 + IFN-γ + IL-17A + lymphocytes in peripheral blood and pleural fluid of TB patients correlated positively with clinical parameters associated with disease severity [25].…”

IP-10 release assays in the diagnosis of tuberculosis infection: current status and future directions

“…Further evidence has since substantiated this discovery and >40 additional biomarkers have been screened for diagnostic potential. Of all investigated markers, it appears that IP-10 is the most consistently expressed in response to antigen challenge, rendering it the most promising alternative marker to IFN-g [18][19][20][21][22][23][24][25][26][27] and a promising means of improving IGRAs [28][29][30][31][32][33][34].…”

The comparative value of pleural fluid adenosine deaminase and neopterin levels in diagnostic utility of pleural tuberculosis

“…It is well known that because of the low number of M. tuberculosis in pleural effusion, sensitivity of various methods of M. tuberculosis identification in pleural fluid is low (10). The highest diagnostic sensitivity, reaching 70-80%, has been observed for PCR methods identifying specific nucleic acid sequences in pleural fluid.…”