Mycobacterium tuberculosis (Mtb) is transmitted via inhalation of aerosolized particles. While alveolar macrophages are thought to play a central role in the acquisition and control of this infection, Mtb also has ample opportunity to interact with the airway epithelium. In this regard, we have recently shown that the upper airways are enriched with a population of non-classical, MR1-restricted, Mtb-reactive CD8+ T cells (MAIT cells). Additionally, we have demonstrated that Mtb-infected epithelial cells lining the upper airways are capable of stimulating IFNγ production by MAIT cells. In this study, we demonstrate that airway epithelial cells efficiently stimulate IFNγ release by MAIT cells as well as HLA-B45 and HLA-E restricted T cell clones. Characterization of the intracellular localization of Mtb in epithelial cells indicates that the vacuole occupied by Mtb in epithelial cells is distinct from DC in that it acquires Rab7 molecules and does not retain markers of early endosomes such as Rab5. The Mtb vacuole is also heterogeneous as there is a varying degree of association with Lamp1 and HLA-I. Although the Mtb vacuole shares markers associated with the late endosome, it does not acidify, and the bacteria are able to replicate within the cell. This work demonstrates that Mtb infected lung epithelial cells are surprisingly efficient at stimulating IFNγ release by CD8+ T cells.

NF-κB-inducing kinase (NIK) is an essential upstream kinase in noncanonical NF-κB signaling. NIK-dependent NF-κB activation downstream of several TNF receptor family members mediates lymphoid organ development and B cell homeostasis. Peripheral T cell populations are normal in the absence of NIK, but the role of NIK during in vivo T cell responses to antigen has been obscured by other developmental defects in NIKdeficient mice. Here, we have identified a T cell-intrinsic requirement for NIK in graft-versus-host disease (GVHD), wherein NIK-deficient mouse T cells transferred into MHC class II mismatched recipients failed to cause GVHD. Although NIK was not necessary for antigen receptor signaling, it was absolutely required for costimulation through the TNF receptor family member OX40 (also known as CD134). When we conditionally overexpressed NIK in T cells, mice suffered rapid and fatal autoimmunity characterized by hyperactive effector T cells and poorly suppressive Foxp3 + Tregs. Together, these data illuminate a critical T cell-intrinsic role for NIK during immune responses and suggest that its tight regulation is critical for avoiding autoimmunity.

Despite widespread use of the Bacillus Calmette-Guerin vaccine, tuberculosis, caused by infection with Mycobacterium tuberculosis, remains a leading cause of morbidity and mortality worldwide. As CD8+ T cells are critical to tuberculosis host defense and a phase 2b vaccine trial of modified vaccinia Ankara expressing Ag85a that failed to demonstrate efficacy, also failed to induce a CD8+ T cell response, an effective tuberculosis vaccine may need to induce CD8+ T cells. However, little is known about CD8, as compared to CD4, antigens in tuberculosis. Herein, we report the results of the first ever HLA allele independent genome-wide CD8 antigen discovery program. Using CD8+ T cells derived from humans with latent tuberculosis infection or tuberculosis and an interferon-γ ELISPOT assay, we screened a synthetic peptide library representing 10% of the Mycobacterium tuberculosis proteome, selected to be enriched for Mycobacterium tuberculosis antigens. We defined a set of immunodominant CD8 antigens including part or all of 74 Mycobacterium tuberculosis proteins, only 16 of which are previously known CD8 antigens. Immunogenicity was associated with the degree of expression of mRNA and protein. Immunodominant antigens were enriched in cell wall proteins with preferential recognition of Esx protein family members, and within proteins comprising the Mycobacterium tuberculosis secretome. A validation study of immunodominant antigens demonstrated that these antigens were strongly recognized in Mycobacterium tuberculosis-infected individuals from a tuberculosis endemic region in Africa. The tuberculosis vaccine field will likely benefit from this greatly increased known repertoire of CD8 immunodominant antigens and definition of properties of Mycobacterium tuberculosis proteins important for CD8 antigenicity.

Infection with Mycobacterium tuberculosis (Mtb), the bacterium that causes tuberculosis, remains a global health concern. Both classically and non-classically restricted cytotoxic CD8+ T cells are important to the control of Mtb infection. We and others have demonstrated that the non-classical MHC I molecule HLA-E can present pathogen-derived peptides to CD8+ T cells. In this manuscript, we identified the antigen recognized by an HLA-E-restricted CD8+ T cell clone isolated from an Mtb latently infected individual as a peptide from the Mtb protein, MPT32. Recognition by the CD8+ T cell clone required N-terminal O-linked mannosylation of MPT32 by a mannosyltransferase encoded by the Rv1002c gene. This is the first description of a post-translationally modified Mtb-derived protein antigen presented in the context of an HLA-E specific CD8+ T cell immune response. The identification of an immune response that targets a unique mycobacterial modification is novel and may have practical impact in the development of vaccines and diagnostics.

Background The proportion of tuberculosis (TB) patients who are older adults is increasing worldwide. Nearly 60% of TB patients in Japan are 70 years or older, and the TB incidence rate in Japan is one of the highest among high-income countries. The previous TB treatment guidelines prior to 2018 in Japan recommended excluding pyrazinamide (PZA) from the initial regimen for patients aged over 80 years. Objectives We aimed to examine differences in TB treatment outcomes among different age groups, and between those who received PZA and those who did not. Methods We performed a retrospective cohort study of patients with pulmonary TB who were managed at a single medical center in Japan. We compared treatment outcomes and adverse events that resulted in treatment interruption across the age groups. Results Of 246 patients, 117 (48%) were aged 75 years or older. Compared with patients aged < 74 years, those ≥ 75 years were less likely to have PZA in the initial regimen (53.0% vs 89.9%; p < 0.0001), more likely to die during treatment (38.5% vs 6.2%; p < 0.0001), and more likely to experience adverse events (30.8% vs 19.4%; p < 0.05). The mortality rate related to TB at 2 months after TB treatment initiation was 28% in those aged ≥ 84 years. Furthermore, among patients aged ≥ 84 years, those who did not receive PZA were significantly more likely to die than those who did (65.8% vs 36.8%; p < 0.05). Conclusions Patients aged ≥ 75 years with pulmonary TB experienced increased mortality related to TB during treatment and more frequent adverse events than younger patients, even though PZA was often avoided among older patients. Supplementary Information The online version contains supplementary material available at 10.1007/s40266-021-00880-4.

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Background US guidelines now recommend that all HIV-infected persons receive antiretroviral therapy). HIV prevention is increasingly focused on ensuring that infected persons are diagnosed soon after HIV acquisition and quickly link to care and initiate antiretroviral therapy. We examined trends in time from HIV diagnosis to viral load suppression in King County, WA, to gauge improvement in our HIV care continuum over time. Methods We used HIV surveillance data and Cox proportional hazards to evaluate how the time from diagnosis to viral suppression changed among persons newly diagnosed as having HIV in King County, WA, between 2007 and 2013. Results A total of 1490 (84%) of 1766 newly diagnosed persons achieved viral suppression in a median time of 213 days (95% confidence interval, 203–229). Thirty-six percent of all persons diagnosed in 2007 and 77% in 2013 were virally suppressed within 12 months of HIV diagnosis (P < 0.0001). Differences in time to suppression by calendar year persisted when stratifying by CD4 count at diagnosis. Race was not significantly associated with time to viral suppression. Conclusions Time from HIV diagnosis to viral suppression dramatically declined between 2007 and 2013, and more than three quarters of recently HIV-diagnosed individuals in King County, WA, now achieve viral suppression within a year of diagnosis. This improvement was evident among all persons newly diagnosed as having HIV, regardless of race/ethnicity or CD4 count at time of diagnosis.

Incarcerated PLWHA are disproportionately virally nonsuppressed compared with nonincarcerated PLWHA up to a year after release from jail. Public Health Implications. Coordination of health information exchange between the health department and jails could enhance public health efforts to improve the HIV care continuum.