Multiple mycobacterial antigens are targets of the adaptive immune response in pulmonary sarcoidosis

Abstract

IntroductionSarcoidosis is a multisystem granulomatous disease for which the association with mycobacteria continues to strengthen. It is hypothesized that a single, poorly degradable antigen is responsible for sarcoidosis pathogenesis. Several reports from independent groups support mycobacterial antigens having a role in sarcoidosis pathogenesis. To identify other microbial targets of the adaptive immune response, we tested the ability of CD4+ and CD8+ T cells to recognize multiple mycobacterial antigens.MethodsFifty-four subjects were enrolled in this study: 31 sarcoidosis patients, nine non-tuberculosis mycobacterial (NTM) infection controls, and 14 PPD- controls. Using flow cytometry, we assessed for Th1 immune responses to ESAT-6, katG, Ag85A, sodA, and HSP.ResultsAlveolar T-cells from twenty-two of the 31 sarcoidosis patients produced a CD4+ response to at least one of ESAT-6, katG, Ag85A, sodA, or HSP, compared to two of 14 PPD- controls (p = 0.0008) and five of nine NTM controls (p = 0.44), while eighteen of the 31 sarcoidosis subjects tested produced a CD8+ response to at least one of the mycobacterial antigens compared to two of 14 PPD- controls (p = 0.009) and three of nine NTM controls (0.26). Not only did the BAL-derived T cells respond to multiple virulence factors, but also to multiple, distinct epitopes within a given protein. The detection of proliferation upon stimulation with the mycobacterial virulence factors demonstrates that these responses are initiated by antigen specific recognition.ConclusionsTogether these results reveal that antigen-specific CD4+ and CD8+ T cells responses to multiple mycobacterial epitopes are present within sites of active sarcoidosis involvement, and that these antigen-specific responses are present at the time of diagnosis.

Antigen-specific multifunctional T-cells in sarcoidosis patients with Löfgren’s syndrome

“…For example, it was shown that BAL cells from sarcoidosis patients reacted to mycobacterial antigens but not to keyhole limpet haemocyanin, demonstrating antigen specificity [13,28]. Likewise, peripheral blood cells from a majority of sarcoidosis patients responded to stimulation with mycobacterial antigens but not lysate from Trypanosoma brucei [29].…”

Interferon Gamma Release Assays Based on M. tuberculosis-specific Antigens in Sarcoidosis Patients

“…The same author in his subsequent paper reported that ESAT-6 induces the most frequent stimulation of Th1 immune response in these patients, as compared to katG, Ag85A, sodA and Hsp70 [19]. Recently, Oswald-Richter et al, using matrix-assisted laser desorption ionization imaging mass spectrometry localized signal consistent with antigen ESAT-6 in sarcoidosis granulomas [20].…”

Blockade of the Programmed Death-1 Pathway Restores Sarcoidosis CD4+ T-Cell Proliferative Capacity

“…Surface staining of cells was performed as previously described (12). Th17 cells were identified using flow cytometry as previously described (28 For the blockade experiments, PBMC were labeled with carboxyfluorescein succinimidyl ester as previously described (23), then incubated overnight with or without the combination of anti-PD-1(5 mg/ml, J116; eBioscience, San Diego, CA), anti-PD-L1(2 mg/ml, MIH1; eBioscience), and anti-PD-L2 (2 mg/ml, MIH18; eBioscience) blocking antibodies in RPMI 1640-supplemented medium before stimulation with anti-CD3 and anti-CD28 antibodies. Cells were then stimulated with plate-bound anti-CD3 antibody (OKT-3; American Type Culture Collection, Manassas, VA) and soluble anti-CD28 antibody (1 mg/ml, BD Biosciences) at a concentration of 2 3 10 6 /ml for 5 days.…”