Mycobacterium Tuberculosis Latent Infection And The Onset Of Tuberculosis In Patients With Immune Molecules Identified By Screening

WHO had reported that one third of the global population had been infected by mycobacterium tuberculosis (M.tb) confirmed to be the pathogen of causing tuberculosis (TB) development. There are generally three M.tb-infection outcomes:(1) the invaded pathogen could be immediately eradicated (<5%infection cases);(2) infections transforms into tuberculosis (5～10%infection cases);(3) infections does not transform into disease because M. tb is contained inside granulomas, and the infected case turns into latent TB (>90%cases). So the M.tb infected population is a complicated case and, cell-mediated immune response plays an important role in deciding clinical disease happening, developing, and other M.tb-infection outcomes happening. In this article, our purpose is to screen and study cell-mediated immune responses' genes in host and, besides IFN-y, to find a group of immunological signatures with distinct characteristics of different M.tb-infection state and disease. Finally we hope these new found immunological signatures could be an important data for further TB study.Part1:Screening and studying of Immunological Signatures of M.tb infected individuals and primary TB patientsWe identified M.tb-infected latent TB by using tuberculin skin test (TST) and in vitro M.tb specific antigen IFN-γ release assay (ELISPOT). And then through using the level of IFN-y release assay, the latent TB was divided into two groups, which included LTB1with low IFN-γ release level and LTB2with high IFN-γ release level. All patients were primary TB, which excluded from suffering HIV infection, autoimmune disease and immunosuppressant application. All healthy donors had negative results of TST and IFN-y release assay test.So, in our article, the latent TB was divided into two different groups which had distinct feature of M.tb antigen specific IFN-γ response.As CD4+T cells mediated immune response plays an important role in TB development and this had been confirmed by many literatures. So in part1, we studied the gene expression profile of CD4+T cells in HD, LTB1, LTB2and TB. And then, in the four groups HD, LTB1, LTB2and TB, we measured the expression level of the genes of TNFSFs and TNFRSFs in CD4+T cells, non-CD4T cells (CD4+T cells depleted PBMC), serum of TB, PFL and PFMC of tuberculous pleurisy. As follows: 1. The results of gene expression profile of CD4+T cells shown that:by clustering method, we found the LTB1with low IFN-γ release level had a distinct gene expression profile of CD4+T cells with LTB2with high IFN-γ release level; however, LTB1had a similar gene expression profile of CD4+T cells with healthy donor with TST negative results.2. Verified results of TNFSF13(APRIL),TNFSF13B (BAFF) suggested that BAFF/ARRIL signaling pathway might play a role in tuberculosis development. Both of mRNA in CD4+T cells and protein in serum of BAFF and APRIL were elevated in TB patient. Especially the protein level in PFL is higher than in serum of primary TB patients. So TNFSF13(APRIL) and TNFSF13B (BAFF) might could be used to forecast the state of M.tb-infection.Part2:Measuring the T cells-related genes in M.tb infected latent individuals and primary TB patient by using real time PCR and testing cytokines and chemokines in body fluidAs the CD4+T cells mediated immune responses are complicated cases, which could simultaneously have several different cell types and play different role in immune responses. In part2, we tested expression level of differentiation related genes in T cells by real time PCR and wanted to get basics of the relationship between these genes' expression and TB development. Our results showed that not only Thl and Th2take part in TB development, but also the other cell types, such as Th17and Treg, also play an important role in TB development. As follows:1. Th17-related genes RORc had a significant down-regulation expression in LTB1and TB groups. IL-6R related signal is needed for Th17production, and IL6ST/gp130is one of signal molecules in this signaling pathway. Our verified results also shown that IL6ST/gp130was significant down-regulation expression.2. FOXP3is one of markers of Treg. Its expression was tested to be significant down-regulation in LTB2and TB. S1PR1has an inhibition role in Treg forming; we found S1PR1was significant down-regulation in LTB1, LTB2and TB groups. Simultaneously, in order to find some molecules with characteristic of easy detection and forecasting TB development, we also tested23common cytokines and chemokines' level by lumines in serum and PFL of TB patients. As follows:1. The level of IFN-γ, IL-1Rα, IL-6and G-CSF were found to be up-regulation in PFL of tuberculous pleurisy.2. As many literatures reported that IFN-γ and G-CSF could stimulate many cell types to synthesize or increase TNFSF13(APRIL) and TNFSF13B (BAFF) production, the level of IFN-γ and G-CSF increase in PFL might explain why APRIL and BAFF level were very high in PFL of tuberculous pleurisy.So, in this article, by studying the expression level of T cell related genes in distinct state of latent M.tb infected individuals and primary TB patients, we first found that TNFSF13B (BAFF) and TNFSF13(APRIL) could take part in TB development. Although the details of function of both genes were still to be studied in future, testing the level of TNFSF13B (BAFF) and TNFSF13(APRIL) is valuable to forecast TB development.