Tuberculosis Immunity Research Articles

Varied presentation of tuberculosis adenopathy: an immunological and diagnostic contemplation

Tuberculous lymphadenitis is the most common presentation of extra pulmonary tuberculosis EPTB. Clinical and radiological presentation of disease may vary and differential diagnosis includes both benign and malignant conditions such as lymphomas and sarcoidosis. We present two case reports of tuberculous lymphadenitis with varied presentation. In case report Ⅰ, patient had undergone splenectomy due to traumatic splenic rupture had classical symptoms of tuberculosis, chest X-ray, CT thorax showed mediastinal and cervical lymphadenopathy. FNAC showed a picture of granulomatous lesion. In case report ⅠⅠ patient came with complaints of abdominal pain in hypochondriac region. CT and USG abdomen showed multiple enlarged retroperitoneal lymph nodes which led to a provisional diagnosis of lymphoma after which lymph node biopsy showed a granulomatous picture. This case report stresses the importance of early and quick diagnosis of tuberculosis in immunocompromised patients and highlights the risk of misdiagnosis of tuberculous lymphadenitis with other benign and malignant causes of lymphadenopathy and the importance of humoral mediated immunity in tuberculosis.

Th22 Cells Are a Major Contributor to the Mycobacterial CD4+ T Cell Response and Are Depleted During HIV Infection.

HIV-1 infection substantially increases the risk of developing tuberculosis (TB). Mechanisms such as defects in the Th1 response to Mycobacterium tuberculosis in HIV-infected persons have been widely reported. However, Th1-independent mechanisms also contribute to protection against TB. To identify a broader spectrum of defects in TB immunity during HIV infection, we examined IL-17A and IL-22 production in response to mycobacterial Ags in peripheral blood of persons with latent TB infection and HIV coinfection. Upon stimulating with mycobacterial Ags, we observed a distinct CD4+ Th lineage producing IL-22 in the absence of IL-17A and IFN-γ. Mycobacteria-specific Th22 cells were present at high frequencies in blood and contributed up to 50% to the CD4+ T cell response to mycobacteria, comparable in magnitude to the IFN-γ Th1 response (median 0.91% and 0.55%, respectively). Phenotypic characterization of Th22 cells revealed that their memory differentiation was similar to M. tuberculosis-specific Th1 cells (i.e., predominantly early differentiated CD45RO+CD27+ phenotype). Moreover, CCR6 and CXCR3 expression profiles of Th22 cells were similar to Th17 cells, whereas their CCR4 and CCR10 expression patterns displayed an intermediate phenotype between Th1 and Th17 cells. Strikingly, mycobacterial IL-22 responses were 3-fold lower in HIV-infected persons compared with uninfected persons, and the magnitude of responses correlated inversely with HIV viral load. These data provide important insights into mycobacteria-specific Th subsets in humans and suggest a potential role for IL-22 in protection against TB during HIV infection. Further studies are needed to fully elucidate the role of IL-22 in protective TB immunity.

Revising the model for vaccine development: a step towards tuberculosis immunity

Thanks to accelerated vaccine development, the first COVID-19 vaccine was approved for use by Health Canada only nine months after the disease was declared a pandemic by the World Health Organization [1]. This unprecedented feat was made possible by three critical factors: a stressed sense of urgency, substantial funding, and parallel pre-clinical and clinical trials. Such a concerted effort not only led to the development of multiple effective vaccines, but also bred innovation as mRNA technology bloomed despite its limited use in the past. This success story paves the way for the accelerated development of vaccines for other diseases, such as tuberculosis—the deadliest infectious disease of modern times before COVID-19 emerged.

Prof. G. D. Belonovsky. Immunity in tuberculosis. "Prak. Med.", 1922

Prof. B.'s pamphlet is a summary of works on tuberculosis immunity. The very name of its author speaks for its scientific and authoritative nature. The latter very modestly declares in the preface that his work claims neither originality nor completeness; in fact, he has covered this part of the tuberculosis doctrine with almost complete completeness.

Characterizing Early T Cell Responses in Nonhuman Primate Model of Tuberculosis.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a leading infectious disease killer worldwide with 1.4 million TB deaths in 2019. While the majority of infected population maintain an active control of the bacteria, a subset develops active disease leading to mortality. Effective T cell responses are critical to TB immunity with CD4+ and CD8+ T cells being key players of defense. These early cellular responses to TB infection have not yet been studied in-depth in either humans or preclinical animal models. Characterizing early T cell responses in a physiologically relevant preclinical model can provide valuable understanding of the factors that control disease development. We studied Mtb-specific T cell responses in the lung compartment of rhesus macaques infected with either a low- or a high-dose of Mtb CDC1551 via aerosol. Relative to baseline, significantly higher Mtb-specific CD4+IFN-γ+ and TNF-α + T cell responses were observed in the BAL of low dose infected macaques as early as week 1 post TB infection. The IFN-γ and TNF-a response was delayed to week 3 post infection in Mtb-specific CD4+ and CD8+T cells in the high dose group. The manifestation of earlier T cell responses in the group exposed to the lower Mtb dose suggested a critical role of these cytokines in the antimycobacterial immune cascade, and specifically in the granuloma formation to contain the bacteria. However, a similar increase was not reflected in the CD4+ and CD8+IL-17+ T cells at week 1 post infection in the low dose group. This could be attributed to either a suppression of the IL-17 response or a lack of induction at this early stage of infection. On the contrary, there was a significantly higher IL-17+ response in Mtb-specific CD4+ and CD8+T cells at week 3 in the high dose group. The results clearly demonstrate an early differentiation in the immunity following low dose and high dose infection, largely represented by differences in the IFN-γ and TNF-α response by Mtb-specific T cells in the BAL. This early response to antigen expression by the bacteria could be critical for both bacterial growth control and bacterial containment.

Immunity indicators in tuberculosis patients with diabetes mellitus and autoimmune thyroiditis

Objective — to study the parameters of immunity in tuberculosis with diabetes mellitus and with subclinical hypothyroidism against the background of autoimmune thyroiditis. 
 Materials and methods. 60 patients with pulmonary tuberculosis and diabetes mellitus were under observation. In 30 patients with destructive tuberculosis and diabetes mellitus against the background of autoimmune thyroiditis with subclinical hypothyroidism, the parameters of humoral and cellular immunity were studied. The control group consisted of 30 patients with destructive tuberculosis and diabetes mellitus with intact structure and function of the thyroid gland. In patients of both groups, we assessed the state of T- and B-systems of immunity, natural killers. 
 Results and discussion. The phenotyping of lymphocytes was carried out and the relative content of T-cells was determined: CD3+, T-helpers (CD4+), cytotoxic T-cells, B-lymphocytes (CD19+) and natural killer cells (CD16+). Using the enzyme immunoassay, the cytokine profile was determined: the levels of tumor necrosis factor-α, interferon-γ, interleukin-2, -6 and -4. It has been established that in patients with diabetes mellitus, both cellular and humoral immunity are suppressed. But a significantly more significant suppression of immunity was diagnosed in patients with tuberculosis against the background of diabetes mellitus and autoimmune thyroiditis with subclinical hypothyroidism. 
 Conclusions. According to the authors, it is the deficiency of thyroid hormones that is the negative effect of a more significant suppression of immunity in patients autoimmune thyroiditis with subclinical hypothyroidism.

The Brontës and Tuberculosis Immunity

Tuberculosis killed five of the Brontë siblings, and yet neither Patrick nor Charlotte Brontë succumbed to it. Was this simply a matter of luck, or had Charlotte and her father developed immunity to the infectious, and frequently fatal, disease? By examining their lives and backgrounds we will determine whether tuberculosis immunity is likely to be the reason that Patrick and Charlotte Brontë escaped the consumption which decimated their family. We will also examine the portrayal of tuberculosis within the Brontë writing and see how this compared to their real life experiences. It will also be seen that whilst the threat of tuberculosis was central to the Brontë story in the nineteenth century, it also contains similarities to the Covid-19 threat which is transforming the world today.

Advax adjuvant formulations promote protective immunity against aerosol Mycobacterium tuberculosis in the absence of deleterious inflammation and reactogenicity

The development of safe and effective adjuvants is a critical goal of vaccine development programs. In this report, we defined the immunostimulatory profile and protective effect against aerosol Mycobacterium tuberculosis infection of vaccine formulations incorporating the semi-crystalline adjuvant δ-inulin (Advax). Advax formulated with CpG oligonucleotide and the QS-21 saponin (AdvaxCpQS) was the most effective combination, demonstrated by the capacity of CysVac2/AdvaxCpQS to significantly reduce the bacterial burden in the lungs of M. tuberculosis-infected mice. CysVac2/AdvaxCpQS protection was associated with rapid influx of neutrophils, macrophages and monocytes to the site of vaccination and the induction of antigen-specific IFN-γ+/IL-2+/TNF+ polyfunctional CD4+ T cells in the lung. When compared to the highly potent adjuvant combination of monophosphoryl lipid A and dimethyldioctadecylammonium bromide (MPL/DDA), AdvaxCpQS imparted a similar level of protective efficacy yet without the profound stimulation of inflammatory cytokines and vaccination site ulceration observed with MPL/DDA. Addition of DDA to CysVac2/AdvaxCpQS further improved the protective effect of the vaccine, which correlated with increased polyfunctional CD4+ T cells in the lung but with no increase in vaccine reactogenicity. The data demonstrate that Advax formulations can decouple protective tuberculosis immunity from reactogenicity, making them ideal candidates for human application.

24780 Investigating the role of mycobacterial lipid antigens and CD1-restricted T cells in host-protective tuberculosis immunity using a guinea pig model

ABSTRACT IMPACT: Examining lipid immunity for Mycobacterium tuberculosis in a translatable Guinea pig model may serve as a critical foundation for the creation of an efficacious human lipid based vaccine against tuberculosis. OBJECTIVES/GOALS: CD1 is a group of glycoproteins on antigen-presenting cells (APCs) that present lipid antigens to T cells. Mycobacterium tuberculosis (Mtb) has a lipid-rich cell wall which is essential for the pathogenesis of tuberculosis. Our goal is to determine the frequency, phenotypes, and functionality of CD1 T cells against Mtb using the guinea pig model. METHODS/STUDY POPULATION: Guinea pigs serve as the best translational model for CD1 immunology as they have both group 1 and group 2 CD1 complexes, comparable to human CD1. We performed ex-vivo and in-vivo experiments to analyze lipid antigen-specific CD1 T cell responses with Mtb infection. Assays to detect lipid-specific CD1 T cell activation include cellular proliferation, cytotoxicity assays, and interferon-gamma (IFNγ) release assay (Elispot) using both synthetic and Mtb-derived lipids. We isolated and characterized CD1 T cells using tetramerized CD1 complexes loaded with specific Mtb lipids. Spatial interaction between lipid loaded CD1 APCs with CD1 T cells were demonstrated by immunohistochemistry (IHC). Lastly, we will investigate the impact of lipid-based immunology via knockdown and overexpression of CD1 complexes. RESULTS/ANTICIPATED RESULTS: The cytotoxicity assay demonstrated that the CD1b1 and CD1b3 complexes play roles in the presentation of Mtb lipids, specifically glucose monomycolate, and mycolic acid, as noted by T cell killing of fibroblasts that express specific CD1 complexes that can present Mtb lipids. Similarly, cellular proliferation exhibited lipid specific T cell proliferation. IFNγ production by the stimulated CD1-restricted T cells (Elispot) was weak indicating CD1 T cells may not produce IFNγ. IHC successfully showed CD1 APCs in lungs and spleens of infected guinea pigs. It is anticipated that knocking out CD1 expression will lead to impaired immunity, and increase severity of disease as noted by pathologic lesions/bacterial burden, and systemic spread; in contrast, CD1 enhancement will limit the severity of tuberculosis. DISCUSSION/SIGNIFICANCE OF FINDINGS: We characterized CD1 T cells in infected guinea pigs at the tissue level, demonstrating Mtb lipid immunology. As a result, we laid the groundwork for investigating whether augmenting lipid immunity in the guinea pig model will enhance immunity against tuberculosis. Fruition of such work may lead to the development of effective tuberculosis vaccines.

Mechanisms of development of medicine stability <i>Mycobacterium tuberculosis</i>: is there a chance to win?

The scientific review provides current information on the current epidemiological status of tuberculosis in our country and the world, genetic adaptability and the evolution of Mycobacterium tuberculosis. The well-known and recently discovered molecular targets of aggression of this microorganism are described, and possible methods of circumventing the resistance of the Office to existing and developed drugs are presented. Objective: to create a scientific analytical review, which allows you to form an idea of the basic principles of development of the mechanisms of drug resistance of M. tuberculosis, as well as ways to overcome them with the possibility of further development of the chosen direction with the involvement of reputable scientific groups and practical implementation. Methods. scientific analysis of international reports, highly indexed scientific articles and clinical protocols. Results. Ihanks to the conducted analytical work, critical biological markers of M. tuberculosis immunity to anti-tuberculosis therapy were identified, which protect it from pharmacological intervention by the person and do not adequately sanitize the centers of inflammation in the patient's body. Methods have been proposed for disintegrating the mechanisms of drug resistance, which will bring the algorithms for treating tuberculosis infection to a new level. Conclusion. The analyzed information will contribute to deepening and expanding the knowledge of specialists involved in the fight against tuberculosis about the importance of implementing a personalized approach in the provision of medical care to TB patients, taking into account the studied molecular indicators of resistance to standardized and developed drugs.

The role of donor-unrestricted T-cells, innate lymphoid cells, and NK cells in anti-mycobacterial immunity.

Vaccination strategies against mycobacteria, focusing mostly on classical T‐ and B‐cells, have shown limited success, encouraging the addition of alternative targets. Classically restricted T‐cells recognize antigens presented via highly polymorphic HLA class Ia and class II molecules, while donor‐unrestricted T‐cells (DURTs), with few exceptions, recognize ligands via genetically conserved antigen presentation molecules. Consequently, DURTs can respond to the same ligands across diverse human populations. DURTs can be activated either through cognate TCR ligation or via bystander cytokine signaling. TCR‐driven antigen‐specific activation of DURTs occurs upon antigen presentation via non‐polymorphic molecules such as HLA‐E, CD1, MR1, and butyrophilin, leading to the activation of HLA‐E–restricted T‐cells, CD1‐restricted T‐cells, mucosal‐associated invariant T‐cells (MAITs), and TCRγδ T‐cells, respectively. NK cells and innate lymphoid cells (ILCs), which lack rearranged TCRs, are activated through other receptor‐triggering pathways, or can be engaged through bystander cytokines, produced, for example, by activated antigen‐specific T‐cells or phagocytes. NK cells can also develop trained immune memory and thus could represent cells of interest to mobilize by novel vaccines. In this review, we summarize the latest findings regarding the contributions of DURTs, NK cells, and ILCs in anti–M tuberculosis, M leprae, and non‐tuberculous mycobacterial immunity and explore possible ways in which they could be harnessed through vaccines and immunotherapies to improve protection against Mtb.

RegX3-Mediated Regulation of Methylcitrate Cycle in Mycobacterium smegmatis.

Mycobacterium tuberculosis is a global human pathogen that infects macrophages and can establish a latent infection. Emerging evidence has established the nutrients metabolism as a key point to study the pathogenesis of M. tuberculosis and host immunity. It was reported that fatty acids and cholesterol are the major nutrient sources of M. tuberculosis in the period of infection. However, the mechanism by which M. tuberculosis utilizes lipids for maintaining life activities in nutrient-deficiency macrophages is poorly understood. Mycobacterium smegmatis is fast-growing and generally used to study its pathogenic counterpart, M. tuberculosis. In this work, we found that the phosphate sensing regulator RegX3 of M. smegmatis is required for its growing on propionate and surviving in macrophages. We further demonstrated that the expression of prpR and related genes (prpDBC) in methylcitrate cycle could be enhanced by RegX3 in response to the phosphate-starvation condition. The binding sites of the promoter region of prpR for RegX3 and PrpR were investigated. In addition, cell morphology assay showed that RegX3 is responsible for cell morphological elongation, thus promoting the proliferation and survival of M. smegmatis in macrophages. Taken together, our findings revealed a novel transcriptional regulation mechanism of RegX3 on propionate metabolism, and uncovered that the nutrients-sensing regulatory system puts bacteria at metabolic steady state by altering cell morphology. More importantly, since we observed that M. tuberculosis RegX3 also binds to the prpR operon in vitro, the RegX3-mediated regulation might be general in M. tuberculosis and other mycobacteria for nutrient sensing and environmental adaptation.

Developing New Anti-Tuberculosis Vaccines: Focus on Adjuvants.

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb) that sits in the top 10 leading causes of death in the world today and is the current leading cause of death among infectious diseases. Although there is a licensed vaccine against TB, the Mycobacterium bovis bacilli Calmette–Guérin (BCG) vaccine, it has several limitations, namely its high variability of efficacy in the population and low protection against pulmonary tuberculosis. New vaccines for TB are needed. The World Health Organization (WHO) considers the development and implementation of new TB vaccines to be a priority. Subunit vaccines are promising candidates since they can overcome safety concerns and optimize antigen targeting. Nevertheless, these vaccines need adjuvants in their formulation in order to increase immunogenicity, decrease the needed antigen dose, ensure a targeted delivery and optimize the antigens delivery and interaction with the immune cells. This review aims to focus on adjuvants being used in new formulations of TB vaccines, namely candidates already in clinical trials and others in preclinical development. Although no correlates of protection are defined, most research lines in the field of TB vaccination focus on T-helper 1 (Th1) type of response, namely polyfunctional CD4+ cells expressing simultaneously IFN-γ, TNF-α, and IL-2 cytokines, and also Th17 responses. Accordingly, most of the adjuvants reviewed here are able to promote such responses. In the future, it might be advantageous to consider a wider array of immune parameters to better understand the role of adjuvants in TB immunity and establish correlates of protection.

Relevance of the Warburg Effect in Tuberculosis for Host-Directed Therapy.

Tuberculosis (TB) was responsible for more deaths in 2019 than any other infectious agent. This epidemic is exacerbated by the ongoing development of multi-drug resistance and HIV co-infection. Recent studies have therefore focused on identifying host-directed therapies (HDTs) that can be used in combination with anti-mycobacterial drugs to shorten the duration of TB treatment and improve TB outcomes. In searching for effective HDTs for TB, studies have looked toward immunometabolism, the study of the role of metabolism in host immunity and, in particular, the Warburg effect. Across a variety of experimental paradigms ranging from in vitro systems to the clinic, studies on the role of the Warburg effect in TB have produced seemingly conflicting results and contradictory conclusions. To reconcile this literature, we take a historical approach to revisit the definition of the Warburg effect, re-examine the foundational papers on the Warburg effect in the cancer field and explore its application to immunometabolism. With a firm context established, we assess the literature investigating metabolism and immunometabolism in TB for sufficient evidence to support the role of the Warburg effect in TB immunity. The effects of the differences between animal models, species of origin of the macrophages, duration of infection and Mycobacterium tuberculosis strains used for these studies are highlighted. In addition, the shortcomings of using 2-deoxyglucose as an inhibitor of glycolysis are discussed. We conclude by proposing experimental criteria that are essential for future studies on the Warburg effect in TB to assist with the research for HDTs to combat TB.

Immune Response toward Mycobacterium Tuberculosis Infection

Understanding the human immune response toward Mycobacterium tuberculosis infection is important for controlling its infection. Its transmission through the air consists of "droplets nuclei" containing TB bacilli. After initial infection, the human body will provide diverse immune responses and will determine different clinico-histopathologic finding. This response starts from innate immunity that consists of phagocytosis by distal alveolar macrophages or nasal microfold cells, then will be continued by dendritic cells to be transferred to mediastinal lymph nodes to induced adaptive immune responses. This response is mediated by cells through IFN- γ signaling which will enhance phagocytosis. If this response is effective, there will be a latent infection with an initial histopathological finding of caseosa granulomas and predominantly followed by chronic granulomas. In a few cases, it can be reactivated via the IL-10 activation pathway and exogenous factors, it will induce a great adaptive immune reaction and provide more severe clinico-histopathological manifestation. The existence of the human body's immune response to Mycobacterium tuberculosis, etiher innate or adaptive immunity will determine the clinical course and pathology that will occur.

Vitamin D deficiency is associated with tuberculosis disease in British children.

BACKGROUND: Basic science, epidemiological and interventional research supports a link between vitamin D and tuberculosis (TB) immunity, infection and disease. We evaluated the association between vitamin D levels and TB infection and disease in UK children recruited to the National Institute for Health Research IGRA Kids Study (NIKS).METHODS: Children presenting between 2011 and 2014 were eligible if they had history of exposure to an adult case with sputum smear/culture-positive TB, or were referred and diagnosed with TB disease. Children were assessed at baseline and at 6-8 weeks for immunological evidence of TB infection (interferon-gamma release assay and/or tuberculin skin test) and evidence of TB disease. Some centres routinely measured total 25-hydroxy vitamin D (25-OHD) levels.RESULTS: A total of 166 children were included. The median 25-OHD levels were higher in non-infected children (45.5 nmol/l) than in those with tuberculous infection (36.2 nmol/l) and TB disease (20.0 nmol/l). The difference between TB infection and disease was statistically significant (P < 0.001). By logistic regression, lower vitamin D levels were associated with TB disease among participants with infection or disease, with no evidence of confounding by age, sex, bacille Calmette-Guérin vaccination status, ethnicity, non-contact referral, season or centre.CONCLUSION: Children with TB disease had lower vitamin D levels than children with infection. Implications for prevention and treatment remain to be established.

GM-CSF Dependent Differential Control of Mycobacterium tuberculosis Infection in Human and Mouse Macrophages: Is Macrophage Source of GM-CSF Critical to Tuberculosis Immunity?

Although classically associated with myelopoiesis, granulocyte-macrophage colony-stimulating factor (GM-CSF) is being increasingly recognized for its potential role in innate resistance against tuberculosis (TB). While the GM-CSF is produced by a variety of host cells, including conventional and non-conventional T cells, macrophages, alveolar epithelial cells, the cell population that promotes GM-CSF mediated innate protection against Mycobacterium tuberculosis infection remains unclear. This is because studies related to the role of GM-CSF so far have been carried out in murine models of experimental TB, which is inherently susceptible to TB as compared to humans, who exhibit a resolution of infection in majority of cases. We found a significantly higher amount of GM-CSF production by human macrophages, compared to mouse macrophages, after infection with M. tuberculosis in vitro. The higher levels of GM-CSF produced by human macrophages were also directly correlated with their increased life span and ability to control M. tuberculosis infection. Other evidence from recent studies also support that M. tuberculosis infected human macrophages display heterogeneity in their antibacterial capacity, and cells with increased expression of genes involved in GM-CSF signaling pathway can control intracellular M. tuberculosis growth more efficiently. Collectively, these emerging evidence indicate that GM-CSF produced by lung resident macrophages could be vital for the host resistance against M. tuberculosis infection in humans. Identification of GM-CSF dependent key cellular pathways/processes that mediate intracellular host defense can lay the groundwork for the development of novel host directed therapies against TB as well as other intracellular infections.

MECHANISMS AND FEATURES OF IMMUNE STATUS AND "OXIDATIVE STRESS - ANTIOXIDANT PROTECTION" SYSTEM IN PATIENTS WITH TUBERCULOSIS

The study of the human immune system state in infection with M. tuberculosis is relevant because the course and outcome of this disease are largely determined by the immune status of the patient. However, 98 % of patients with pulmonary tuberculosis have an immune imbalance. It is known that in the protection against tuberculosis an important role belongs to the body's natural resistance, which is provided by a variety of cellular and humoral factors, physicochemical characteristics of tissues, lymphoid cells, leukocyte and macrophage responses and genetic resistance. When mycobacteria enter the body, polymorphonuclear leukocytes, monocytes and macrophages are the main phagocytic cells. Optimally high level of resistance to the pathogen develops only in the coordinated interaction of T−lymphocytes with macrophages. Studies of cellular immunity and genetic markers have shown that the course of tuberculosis infection is associated with suppression of their functional activity. Immune response deregulation is closely related to oxidative stress, which results from an imbalance between free reactive oxygen species and antioxidant mechanisms, with a higher risk of developing it rather in lungs than other organs. Many studies have presented the results of studying the state of the immune system and the "oxidative stress − antioxidant protection" system in tuberculosis. This is an important component, because the clinical course and outcome of treatment is largely determined by the status of these systems. A number of experts point out that the study of immunological and oxidative parameters in tuberculosis is of a great importance for deciding on the tactics of treatment and the choice of direction of influence on the course of the disease. Key words: M. Tuberculosis, immunity in tuberculosis, oxidative stress, antioxidant protection.

Singapore Ocular Tuberculosis Immunity Study (SPOTIS): Role of T-lymphocyte Profiling in Patients with Presumed Ocular Tuberculosis

ABSTRACT Objective: A prospective clinical study to assess the utility of CD4 + T cell lymphocyte profiling from peripheral blood in patients with ocular tuberculosis (TB). Methods: Thirty-six Asian patients with presumed diagnosis of ocular TB were recruited for T-lymphocyte profiling. MTB antigen specific CD4 assay was set up, and flow cytometric data were analyzed using FlowJo software. Results: There was no significant difference between treatment responders and non-responders for the proportion of CD4 + T cells specific for PPD or ESAT-6+ CFP-10, but treatment responders did have significantly higher frequency of CD38+ (p = .0357) and CD38+ HLA-DR+ (p = .0357) on the PPD-specific CD4 + T cells. Conclusion: This study is one of the first of its kind to look into MTB specific T cell activation marker profiling of peripheral blood in patients with ocular TB. Further studies need to be undertaken to assess the utility of CD4 + T cell phenotypes as a biomarker for ocular TB.

Myeloid C-Type Lectin Receptors in Tuberculosis and HIV Immunity: Insights Into Co-infection?

C-type lectin receptors (CLRs) are carbohydrate binding pattern recognition receptors (PRRs) which play a central role in host recognition of pathogenic microorganisms. Signaling through CLRs displayed on antigen presenting cells dictates important innate and adaptive immune responses. Several pathogens have evolved mechanisms to exploit the receptors or signaling pathways of the CLR system to gain entry or propagate in host cells. CLR responses to high priority pathogens such as Mycobacterium tuberculosis (Mtb), HIV, Ebola, and others are described and considered potential avenues for therapeutic intervention. Mtb and HIV are the leading causes of death due to infectious disease and have a synergistic relationship that further promotes aggressive disease in co-infected persons. Immune recognition through CLRs and other PRRs are important determinants of disease outcomes for both TB and HIV. Investigations of CLR responses to Mtb and HIV, to date, have primarily focused on single infection outcomes and do not account for the potential effects of co-infection. This review will focus on CLRs recognition of Mtb and HIV motifs. We will describe their respective roles in protective immunity and immune evasion or exploitation, as well as their potential as genetic determinants of disease susceptibility, and as avenues for development of therapeutic interventions. The potential convergence of CLR-driven responses of the innate and adaptive immune systems in the setting of Mtb and HIV co-infection will further be discussed relevant to disease pathogenesis and development of clinical interventions.