Th1 CD41 T cells and their derived cytokines are crucial for protection against Mycobacterium tuberculosis. Using multiparametric flow cytometry, we have evaluated the distribution of seven distinct functional states (IFN-c/IL-2/TNF-a triple expressors, IFN-c/IL-2, IFN-c/TNF-a or TNF-a/IL-2 double expressors or IFN-c, IL-2 or TNF-a single expressors) of CD4 1 T cells in individuals with latent M. tuberculosis infection (LTBI) and active tuberculosis (TB). We found that triple expressors, while detectable in 85-90%TB patients, were only present in 10-15% of LTBI subjects. On the contrary, LTBI subjects had significantly higher (12-to 15-fold) proportions of IL-2/IFN-c double and IFN-c single expressors as compared with the other CD4 1 T-cell subsets. Proportions of the other double or single CD4 1 T-cell expressors did not differ between TB and LTBI subjects. These distinct IFN-c, IL-2 and TNF-a profiles of M. tuberculosis-specific CD4 1 T cells seem to be associated with live bacterial loads, as indicated by the decrease in frequency of multifunctional T cells in TB-infected patients after completion of anti-mycobacterial therapy. Our results suggest that phenotypic and functional signatures of CD4 1 T cells may serve as immunological correlates of protection and curative host responses, and be a useful tool to monitor the efficacy of anti-mycobacterial therapy. IntroductionInfections with Mycobacterium tuberculosis (M. tuberculosis) cause a global epidemic with almost 9 million new cases and over 1.6 million deaths per year [1,2]. Outcome of M. tuberculosis infection depends on early identification and proper treatment of individuals with active tuberculosis (TB), but the lack of accurate diagnostic techniques has contributed to the re-emergence of TB as a global health threat. More than 2 billion individuals are estimated to be latently infected with M. tuberculosis (LTBI). To date, however, Ã These authors have contributed equally to this work. There were a number of differences between TB patients and subjects with LTBI following stimulation with ESAT-6, Ag85B and the 16-kDa antigen (Fig. 2). Most notably, and in contrast with the previously reported results in chronic viral infections, we found a significantly higher proportion of 31 CD4 1 T cells simultaneously secreting IFN-g, IL-2 and TNF-a in patients with TB, as compared with LTBI subjects, upon stimulation with any of the three tested M. tuberculosis antigens (Fig. 2). Using a threshold of 0.01% to avoid systematic biases incurred by zeroing negative values (frequency values o0.01% were set to zero), we found that 31 CD4 1 T cells were detectable in very few LTBI subjects (3/18, 3/18 and 2/18 in response to Ag85B, ESAT-6 and 16 kDa, respectively), but were frequently detected in most TB patients (17/20, 18/20 and 17/20, in Eur. J. Immunol. 2010. 40: 2211-2220 Nadia Caccamo et al. 2212& 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.eji-journal.eu response to Ag85B, ESAT-6 and 16 kDa, respectively; see also Table 1 for comparison).In contrast, ...

BackgroundIdiopathic pulmonary fibrosis (IPF) is a progressive and fatal illness whose pathogenesis remains poorly understood. Recent evidence suggests oxidative stress as a key player in the establishment/progression of lung fibrosis in animal models and possibly in human IPF. The aim of the present study was to characterize the cellular phenotype of fibroblasts derived from IPF patients and identify underlying molecular mechanisms.Methodology/Principal FindingsWe first analyzed the baseline differentiation features and growth ability of primary lung fibroblasts derived from 7 histology proven IPF patients and 4 control subjects at different culture passages. Then, we focused on the redox state and related molecular pathways of IPF fibroblasts and investigated the impact of oxidative stress in the establishment of the IPF phenotype. IPF fibroblasts were differentiated into alpha-smooth muscle actin (SMA)-positive myofibroblasts, displayed a pro-fibrotic phenotype as expressing type-I collagen, and proliferated lower than controls cells. The IPF phenotype was inducible upon oxidative stress in control cells and was sensitive to ROS scavenging. IPF fibroblasts also contained large excess of reactive oxygen species (ROS) due to the activation of an NADPH oxidase-like system, displayed higher levels of tyrosine phosphorylated proteins and were more resistant to oxidative-stress induced cell death. Interestingly, the IPF traits disappeared with time in culture, indicating a transient effect of the initial trigger.Conclusions/SignificanceRobust expression of α-SMA and type-I collagen, high and uniformly-distributed ROS levels, resistance to oxidative-stress induced cell death and constitutive activation of tyrosine kinase(s) signalling are distinctive features of the IPF phenotype. We suggest that this phenotype can be used as a model to identify the initial trigger of IPF.

CD8 T-cells contribute to control of Mycobacterium tuberculosis infection, but little is known about the quality of the CD8 T-cell response in subjects with latent infection and in patients with active tuberculosis disease. CD8 T-cells recognizing epitopes from 6 different proteins of Mycobacterium tuberculosis were detected by tetramer staining. Intracellular cytokines staining for specific production of IFN-γ and IL-2 was performed, complemented by phenotyping of memory markers on antigen-specific CD8 T-cells. The ex-vivo frequencies of tetramer-specific CD8 T-cells in tuberculous patients before therapy were lower than in subjects with latent infection, but increased at four months after therapy to comparable percentages detected in subjects with latent infection. The majority of CD8 T-cells from subjects with latent infection expressed a terminally-differentiated phenotype (CD45RA+CCR7−). In contrast, tuberculous patients had only 35% of antigen-specific CD8 T-cells expressing this phenotype, while containing higher proportions of cells with an effector memory- and a central memory-like phenotype, and which did not change significantly after therapy. CD8 T-cells from subjects with latent infection showed a codominance of IL-2+/IFN-γ+ and IL-2−/IFN-γ+ T-cell populations; interestingly, only the IL-2+/IFN-γ+ population was reduced or absent in tuberculous patients, highly suggestive of a restricted functional profile of Mycobacterium tuberculosis-specific CD8 T-cells during active disease. These results suggest distinct Mycobacterium tuberculosis specific CD8 T-cell phenotypic and functional signatures between subjects which control infection (subjects with latent infection) and those who do not (patients with active disease).