Discordance in CD4+T-cell levels and viral loads with co-occurrence of elevated peripheral TNF-α and IL-4 in newly diagnosed HIV-TB co-infected cases

Identification of cytokine signatures in HIV‑infected individuals with and without Mycobacterium tuberculosis co‑infection

Individuals with human immunodeficiency virus (HIV) infection are susceptible to immune system dysregulation, particularly during co-infection with Mycobacterium tuberculosis (MTB). Although there is an association between cytokine profiles and HIV-MTB co-infection, little is known about the cytokine-related host immune response mechanism to HIV-MTB co-infection. Therefore, the present study aimed to analyze expression of cytokines IL-17A, IFN-γ, TNF, IL-2, IL-10, IL-6 and IL-4 in individuals with HIV-MTB co-infection. A total of 30 patients with HIV and 40 with HIV-MTB co-infection were recruited into the present study, including those with active (A) (n=19) and latent (L)TB (n=21). HIV infection status was established based on national HIV guideline (Pedoman Nasional Pelayanan Kedokteran Tatalaksana HIV). ATB was confirmed using a positive acid-fast bacillus staining and culture of sputum; LTB status was established using IFN-γ release assay. Furthermore, the levels of cytokines IL-17A, IFN-γ, TNF, IL-10, IL-6, IL-4 and IL-2 were measured using flow cytometric bead array and CD4 cell count was performed by PIMA™ CD4 assay. IFN-γ, TNF, IL-10, IL-6 and IL-2 were able to significantly differentiate patients with HIV-ATB from those with HIV-LTB. Furthermore, in the patient subgroup with CD4 count <350 cells/µl, IFN-γ, IL-10 and IL-6 were able to differentiate between patients with HIV-ATB and HIV alone, as well as between patients with HIV-ATB and HIV-LTB. Based on these findings, the cytokine profiles are likely to be distinct between individuals with HIV infection with A- and LTB. Furthermore, the expression of CD4-positive T cells may influence the immune response in the body under HIV-MTB co-infection.

T Cell Responses during Human Immunodeficiency Virus/Mycobacterium tuberculosis Coinfection

Coinfection with Mycobacterium tuberculosis (Mtb) and the human immunodeficiency virus (HIV) is a significant public health concern. Individuals infected with Mtb who acquire HIV are approximately 16 times more likely to develop active tuberculosis. T cells play an important role as both targets for HIV infection and mediators of the immune response against both pathogens. This review aims to synthesize the current literature and provide insights into the effects of HIV/Mtb coinfection on T cell populations and their contributions to immunity. Evidence from multiple in vitro and in vivo studies demonstrates that T helper responses are severely compromised during coinfection, leading to impaired cytotoxic responses. Moreover, HIV's targeting of Mtb-specific cells, including those within granulomas, offers an explanation for the severe progression of the disease. Herein, we discuss the patterns of differentiation, exhaustion, and transcriptomic changes in T cells during coinfection, as well as the metabolic adaptations that are necessary for T cell maintenance and functionality. This review highlights the interconnectedness of the immune response and the pathogenesis of HIV/Mtb coinfection.

Immunopathology in human pulmonary tuberculosis: Inflammatory changes in the plasma milieu and impaired host immune cell functions

Host immune response is key for protection in tuberculosis, but the causative agent, Mycobacterium (M.) tuberculosis, manages to survive despite immune surveillance. Key mechanisms of immune protection have been identified, but the role of immunopathology in the peripheral blood of tuberculosis patients remains unclear. Tuberculosis immunopathology in the blood is characterised by patterns of immunosuppression and hyperinflammation. These seemingly contradictory findings and the pronounced heterogeneity made it difficult to interpret the results from previous studies and to derive implications of immunopathology. However, novel approaches based on comprehensive data analyses and revitalisation of an ancient plasma milieu in vitro assay connected inflammation with immunosuppressive factors in tuberculosis. Moreover, interrelations between the aberrant plasma milieu and immune cell pathology were observed. This review provides an overview of studies on changes in plasma milieu and discusses recent findings linking plasma factors to T-cell and monocyte/macrophage pathology in pulmonary tuberculosis patients.

Effects of SNPs on TNF-α and IL-10 cytokine expression in TB and HIV patients in the Capricorn district, Limpopo Province, South Africa

Background

The impact of Tuberculosis (TB) places an immense burden on the health care system. Infection with Human Immunodeficiency Virus (HIV) is a significant risk factor in the development and progression of TB disease. Single Nucleotide Polymorphisms (SNPs) in the promoter region of Interleukin-10 (IL-10) and Tumour Necrotic Factor-Alpha (TNF-α) may play a major role in the disease mechanism and understanding these mechanisms might prove to be a useful diagnostic tool in evaluating the immune regulation and progression of the disease.

Objective

This study aimed to determine the relationship between cytokine levels and gene variants of Interleukin-10 and Tumour Necrotic Factor Alpha in TB and HIV-infected participants.

Methods

Cytokine levels were determined by ELISA, and SNPs were determined by MassArray®.

Results

The levels of TNF-α were higher in the TB group than the HIV (p < 0.001) and TB-HIV (p = 0.011) groups, but similar to the TNF-α levels in the control group. In the HIV group, IL-10 levels were higher than those of the TB (p < 0.001) and control groups (p = 0.039), whereas there was no difference between the IL-10 levels in the HIV and the TB-HIV infection groups. The ratio was determined and there were no differences between the four infection groups. In this study, no associations were detected between the circulating plasma levels of TNF-α and IL-10 and their genotypes.

Conclusion

Our data showed that the gene variants were not associated with circulating plasma levels of TNF-α and IL-10 in our study population. A pro-inflammatory environment was found in the TB and TB-HIV groups, which is suggesting of bacterial clearance, while an anti-inflammatory environment was found in the HIV group, which suggests the suppression of viral replication.

Mycobacterium tuberculosis EspR modulates Th1-Th2 shift by transcriptionally regulating IL-4, steering increased mycobacterial persistence and HIV propagation during co-infection

Mycobacterium tuberculosis (Mtb) and HIV are known to mutually support each other during co-infection by multiple mechanisms. This synergistic influence could be either by direct interactions or indirectly through secreted host or pathogen factors that work in trans. Mtb secretes several virulence factors to modulate the host cellular environment for its persistence and escaping cell-intrinsic immune responses. We hypothesized that secreted Mtb transcription factors that target the host nucleus can directly interact with host DNA element(s) or HIV LTR during co-infection, thereby modulating immune gene expression, or driving HIV transcription, helping the synergistic existence of Mtb and HIV. Here, we show that the Mtb-secreted protein, EspR, a transcription regulator, increased mycobacterial persistence and HIV propagation during co-infection. Mechanistically, EspR localizes to the nucleus of the host cells during infection, binds to its putative cognate motif on the promoter region of the host IL-4 gene, activating IL-4 gene expression, causing high IL-4 titers that induce a Th2-type microenvironment, shifting the macrophage polarization to an M2 state as evident from CD206 dominant population over CD64. This compromised the clearance of the intracellular mycobacteria and enhanced HIV propagation. It was interesting to note that EspR did not bind to HIV LTR, although its transient expression increased viral propagation. This is the first report of an Mtb transcription factor directly regulating a host cytokine gene. This augments our understanding of the evolution of Mtb immune evasion strategies and unveils how Mtb aggravates comorbidities, such as HIV co-infection, by modulating the immune microenvironment.

CD4+ T cell count in HIV/TB co-infection and co-occurrence with HL: Case report and literature review

In the human immunodeficiency virus (HIV)-infected population, especially HIV with concomitant tuberculosis (TB) or Hodgkin's lymphoma (HL), numerous risk factors have been reported in recent years. Among them, the decreased CD4+ T cell count was recognized as the common risk factor. We report a case of a patient with HIV and TB and HL co-occurrence, in which patient's CD4+ T cell count was inconsistent with disease. A 58-year-old male presented with fever and shortness of breath that persisted for 2 months. The patient had a 4-year history of HIV infection and underwent antiretroviral therapy (ART) effectively. After blood test, computed tomography, bone biopsy, and lymphoma biopsy, the patient was diagnosed with skeletal TB and HL, underwent TB treatment and received ART, and underwent four cycles of chemotherapy. CD4+ T cell count was not decreased before diagnosed with TB/HL and increased in this case after the fourth cycle of chemotherapy. We collected and analyzed CD4+ T cell counts in our case and reviewed relevant literature. It is suggested that CD4+ T cell count may be insufficient to predict the risk of HIV-related disease, especially lymphoproliferative disorders.

Interleukin-4 expression is increased in patients with tuberculosis: A systematic review and meta-analysis

BACKGROUND

Interleukin-4 (IL-4) is an important cytokine in the Th2 differentiation of CD4+ T cells, which modulates immune responses and participates in host defense against Mycobacterium tuberculosis. The present study aimed to evaluate the significance of IL-4 concentration in patients with tuberculosis. Data from this study will be helpful in understanding the immunological mechanisms of tuberculosis and in clinical practice.

METHOD

A data search was conducted from January 1995 to October 2022 in electronic bibliographic databases such as China National Knowledge Infrastructure, Wan Fang, Embase, Web of Science, and PubMed. The Newcastle-Ottawa Scale was used to assess the quality of the included studies. Heterogeneity between the studies was assessed using I2 statistics. Publication bias was determined by funnel plot, and Egger's test was used to confirm the presence of publication bias. All qualified studies and statistical analyses were performed using Stata 11.0.

RESULTS

Fifty-one eligible studies comprising 4317 subjects were included in the meta-analysis. The results depicted a considerably increased level of serum IL-4 in patients with tuberculosis than in the controls (standard mean difference [SMD] = 0.630, [95% confidence interval (CI), 0.162-1.092]). However, there was no significant difference in plasma IL-4 levels between patients with TB and controls (SMD = 0.290, [95% CI, -0.430 to 1.010]). In addition, the infection status, TB focus location, drug resistance, race, research design type, and detection method divided the subjects into different subgroups for the meta-analysis. The results of the comparison of healthy controls and TB subjects showed that in the Asian population, the serum IL-4 level in patients with TB was higher than that in controls (SMD = 0.887, [95% CI, 0.202 to -1.573]) and patients with active TB as well as people with pulmonary TB showed increased serum IL-4 levels compared to controls (SMD = 0.689, [95% CI, 0.152-1.226]). In the case of the control group with latent TB, the active TB group had higher serum IL-4 levels than the control group (SMD = 0.920, [95% CI, 0.387-1.452]).

CONCLUSION

The present meta-analysis showed that serum IL-4 varied in healthy individuals and patients with TB. Patients with active TB may also exhibit higher IL-4 concentrations.

Interferon gamma, interleukin 6 and tissue necrosis factor alpha levels among asymptomatic HIV patients in Benin City, Nigeria

BACKGROUND

Morbidity and mortality associated with HIV infection is immune-mediated, and an understanding of HIV immunology will be beneficial in the management of HIV infectionOBJECTIVE: The objective of this research was to measure the levels of TNF-α, IL-6 and IFN-γ in asymptomatic HIV patients and non-HIV subjects, as well as their relationship with CD4 count.

METHOD

Blood samples were collected from 173 subjects, consisting of 125 asymptomatic HIV patients (44 HAART-naïve and 81 on HAART) and 48 non-HIV subjects. The IFN-, IL-6, and TNF- levels in the blood were determined using enzyme-linked immunosorbent assays, and the CD4 count of all participants was determined using flow cytometry.

RESULTS

Regardless of treatment status, the IFN-γ levels of non-HIV subjects were significantly higher than those of HIV patients (p< 0.001). The opposite was true for IL-6, as the levels of IL-6 in non-HIV subjects were significantly lower than those in HAART-naïve HIV patients (p< 0.001) and those on HAART (p< 0.01). TNF-α levels did not differ between HIV patients and their non-HIV counterparts. Generally, the levels of these cytokines was not affected (p> 0.05) by immunosuppression (measured by CD4 count < 200 cells/μL) and there was no significant correlation between CD4 count and these cytokines (p> 0.05).

CONCLUSION

In conclusion, asymptomatic HIV infection decreased IFN-γ, increased IL-6, and had no effect on TNF-α levels, regardless of treatment status. Immunosuppression had no impact on these cytokine levels, and there was no relationship between them and CD4 counts.

Phenotype and function of peripheral blood γδ T cells in HIV infection with tuberculosis

Background

Although γδ T cells play an essential role in immunity against Human Immunodeficiency Virus (HIV) or Mycobacterium tuberculosis (MTB), they are poorly described in HIV infection with tuberculosis (TB).

Methods

The phenotypic and functional properties of peripheral blood γδ T cells in patients with HIV/TB co-infection were analyzed compared to healthy controls and patients with HIV mono-infection or TB by direct intracellular cytokine staining (ICS).

Results

The percentage of Vδ₁ subset in HIV/TB group was significantly higher than that in TB group, while the decreased frequency of the Vδ₂ and Vγ₂Vδ₂ subsets were observed in HIV/TB group than in TB group. The percentage of CD4⁺CD8^- Vδ₂ subset in HIV/TB group was markedly lower than in TB group. However, the percentage of CD4⁺CD8⁺ Vδ₂ subset in HIV/TB group was markedly higher than HIV group or TB group. A lower percentage TNF-α and a higher percentage of IL-17A of Vδ₂ subset were observed in HIV/TB group than that in HIV mono-infection. The percentage of perforin-producing Vδ₂ subset was significantly lower in HIV/TB group than that in HIV group and TB group.

Conclusions

Our data suggested that HIV/TB co-infection altered the balance of γδ T cell subsets. The influence of HIV/TB co-infection on the function of γδ T cells to produce cytokines was complicated, which will shed light on further investigations on the mechanisms of the immune response against HIV and/or MTB infection.

Th1 cytokine gene polymorphism and the corresponding plasma cytokine levels: A comparative study in HIV-1 positive and exposed uninfected infants

The pro-inflammatory (Th1) cytokines namely interleukin (IL)-2, IL-6, IL-12, interferon (IFN)-γ, tumor necrosis factor-α (TNF-α) are vital in the clearance of HIV infection. This prospective cohort study aimed to evaluate the polymorphisms of Th1 cytokine genes and their corresponding plasma cytokine levels in HIV-1 positive and exposed uninfected (EU) infants born to HIV-1 positive mothers. CD4 count, viral load of HIV-1 positive mothers was done using commercially available reagents. Cytokine genotyping analysis and levels were done in 20 HIV-1 positive and 54 EU infants. The polymorphisms of Th1 cytokines were done using the PCR-SSP method. Plasma cytokine levels were estimated using Bio-Plex-Pro cytokine assay (BIO-RAD; USA). Results revealed treatment status of the mothers and viral load were the two confounding factors having a significant effect on HIV status of the infant. TNF-α GG genotype is significantly higher in EU infants as compared with HIV-1 positive infants. GG genotype was associated with high TNF- α levels in HIV-1 positive infants but the difference was not statistically significant. HIV-1 positive infants with -IFN-γ (+874) TT genotype was significantly associated with high IFN-γ levels. To the best of our knowledge, this is the first study reporting the role of Th1 cytokine gene polymorphisms and their corresponding plasma cytokine levels in HIV-1 positive and EU infants from India.

The diagnostic accuracy of Th1 (IFN-γ, TNF-α, and IL-2) and Th2 (IL-4, IL-6 and IL-10) cytokines response in AFB microscopy smear negative PTB- HIV co-infected patients

Acid Fast Bacilli (AFB) microscopy smear remains the most widely used laboratory diagnostic technique for Pulmonary Tuberculosis (PTB) in low-and-middle income countries. Although it is highly specific, the sensitivity varies between 20-80% in immune-competent people, with only 50% case detection among HIV/TB co-infected patients, hence the need to determine the diagnostic accuracy of Th1 and Th2 cytokine response in AFB microscopy smear negative PTB-HIV co-infected patients. A total of 86 participants were recruited; 70 (81.4%) AFB microscopy smear negative and 16 (18.6%) AFB microscopy smear positive. The AFB microscopy smear negative samples were then cultured using Lowenstein Jensen Medium with 46 being culture-negative and 24 being culture-positive. Blood samples were also collected, cultured using QFT-GIT and the supernatant (plasma) harvested to evaluate cytokine profiles using Enzyme-Linked Immunosorbent Assay. IFN-γ (P < 0.001), TNF-α (P = 0.004), IL-2 (P = 0.004) and IL-4 (P = 0.009) median levels were elevated in PTB culture-positive (AFB microscopy smear negative) as compared to PTB culture-negative (AFB microscopy smear negative) participants. Finally, when Th1 cytokines (IFN-γ, TNF-α and IL-2), Th2 cytokines (IL-6 and IL-10) and T cells were included in the logistic regression fit for PTB outcome, the predictive power of discriminating between those who were AFB smear negative in the diagnosis of PTB was good with cross validated area under the curve (AUC) being 0.87 (95% CI: 0.78, 0.96). This study provides evidence for the ability of Th1 and Th2 cytokines to determine PTB status in AFB microscopy smear negative patients co-infected with HIV.

The role of Mycobacterium tuberculosis antigen specific cytokines in determination of acid fast bacilli culture status in pulmonary tuberculosis patients co-infected with human immunodeficiency virus

Introduction

The interaction between Mycobacterium tuberculosis and HIV leads to rapid progression of tuberculosis (TB) and human immunodeficiency virus (HIV)-induced immunosuppression. Diagnosis of TB in these patients is more difficult due to its atypical presentations giving contradicting results. The overall aim of this study was to evaluate the ability of pro-inflammatory cytokine (Th1) and anti-inflammatory cytokine (Th2) to discriminate between culture-positive and -negative smear status in HIV-TB co-infected patients.

Methods

In a prospective cohort, a total of 86 study participants were recruited: 46 culture-negative and 40 culture-positive. Blood and sputum samples were collected from all participants. The blood was then analyzed using FACSCalibur flow cytometer to immunophenotype the cells and ELISA performed for cytokine profiles. Sputum samples were analyzed to determine smear status using direct microscopy and Lowenstein Jensen medium. Statistical analyses were performed using R software. Independent samples t-test was used to compare means between the two groups, while the medians were compared using two-sample Wilcoxon rank sum test. Pearson's Chi-square test was used to compare the proportion of male and female participants across the culture and AFB smear status. In order to determine the predictive power of Th1 and Th2 in discriminating Pulmonary Tuberculosis status (PTB) (culture status was used as a confirmatory test), binary logistic regression models were fitted for Th1 covariates [IFN-γ, TNF-α, IL-2 and IL-12(p70)] and Receiver Operating Characteristic (ROC) curves plotted.

Results

The overall mean age of the participants was 39 years (SD=12), 42% being male. Although, lymphocytes counts were higher in culture-positive relative to culture-negative, the CD8, CD19, and CD16/CD56 were comparable in the two groups. The CD4 counts differed between the two groups (P=0.012). The Th1 showed a better discrimination between culture-positive and -negative PTB individuals; IFN-γ (P=0.001), TNF-α (P=0.001), IL-2 (P=0.001) and IL-12(p70) (P=0.016). The Th2 cytokines (IL-4, IL-6 and IL-10) were comparable between the culture-positive and -negative groups. However, when the combination of Th1 cytokines [IFN-γ, TNF-α, IL-2 and IL-12(p70)] was fitted in binary logistic regression models, the predictive power was high with area under curve (AUC) being 89.7% in discriminating PTB.

Conclusion

This study provides evidence for the ability of a combination of Th1 cytokines in discriminating against culture-positive and culture-negative PTB.

Mycobacterium tuberculosis Zinc Metalloprotease-1 Assists Mycobacterial Dissemination in Zebrafish

Zinc metalloprotease-1 (Zmp1) from Mycobacterium tuberculosis (M.tb), the tuberculosis (TB) causing bacillus, is a virulence factor involved in inflammasome inactivation and phagosome maturation arrest. We earlier reported that Zmp1 was secreted under granuloma-like stress conditions, induced Th2 cytokine microenvironment and was highly immunogenic in TB patients as evident from high anti-Zmp1 antibody titers in their sera. In this study, we deciphered a new physiological role of Zmp1 in mycobacterial dissemination. Exogenous treatment of THP-1 cells with 500 nM and 1 μM of recombinant Zmp1 (rZmp1) resulted in necrotic cell death. Apart from inducing secretion of necrotic cytokines, TNFα, IL-6, and IL-1β, it also induced the release of chemotactic chemokines, MCP-1, MIP-1β, and IL-8, suggesting its likely function in cell migration and mycobacterial dissemination. This was confirmed by Gap closure and Boyden chamber assays, where Zmp1 treated CHO or THP-1 cells showed ∼2 fold increased cell migration compared to the untreated cells. Additionally, Zebrafish-M. marinum based host–pathogen model was used to study mycobacterial dissemination in vivo. Td-Tomato labeled M. marinum (TdM. marinum) when injected with rZmp1 showed increased dissemination to tail region from the site of injection as compared to the untreated control fish in a dose-dependent manner. Summing up these observations along with the earlier reports, we propose that Zmp1, a multi-faceted protein, when released by mycobacteria in granuloma, may lead to necrotic cell damage and release of chemotactic chemokines by surrounding infected macrophages, attracting new immune cells, which in turn may lead to fresh cellular infections, thus assisting mycobacterial dissemination.

High levels of plasma interferon gamma and +874T/A gene polymorphism is associated with HIV-TB co-infection

OBJECTIVE

Tuberculosis (TB) is one of the most frequent opportunistic infections in HIV patients leading to increased morbidity and death rate. This study was carried out to investigate the role of the cytokines IFN-γ and TNF-α level and their single nucleotide polymorphisms (SNPs) in HIV-TB co-infection.

METHODS

247 HIV-TB (124 HIV-pulmonary TB, 123 HIV-extra pulmonary TB), 126 HIV positive individuals without tuberculosis and 129 healthy subjects (HS) were included to measure plasma levels of IFN-γ and TNF-α by sandwich ELISA and One way ANOVA statistical analysis was carried out among the groups. The SNPs of TNF-α-308 G/A, -238 G/A and IFN-γ+874 T/A were also investigated using amplification refractory mutation system polymerase chain reaction (ARMS-PCR). The frequencies between the groups were compared by Pearson's chi square statistical analysis.

RESULTS

Plasma IFN-γ and TNF-α were significantly elevated in HIV-TB and TB (p<0.05) as compared to those in HS group. There was significant association between IFN-γ+874 'A' allele and AA genotype in HIV-TB groups compared to HS and HIV (p<0.05) and no such association was found for TNF-α-308 and -238. The plasma cytokine levels of TNF-α and IFN-γ reveals no significant association with levels of IFN-γ+874 T/A, TNF-α -308 G/Aand-238 G/A genotypes in any of the study groups.

CONCLUSION

In conclusion, the present study revealed elevated plasma IFN-γ and its +874 'A' allele are associated with HIV-TB co-infection indicating 1.6 times increased risk for TB susceptibility. Elevated TNF-α levels in TB and HIV-TB suggest its involvement in TB pathogenesis.

Mycobacterium tuberculosis Zinc Metalloprotease-1 Elicits Tuberculosis-Specific Humoral Immune Response Independent of Mycobacterial Load in Pulmonary and Extra-Pulmonary Tuberculosis Patients

Conventionally, facultative intracellular pathogen, Mycobacterium tuberculosis, the tuberculosis (TB) causing bacilli in human is cleared by cell-mediated immunity (CMI) with CD4⁺ T cells playing instrumental role in protective immunity, while antibody-mediated immunity (AMI) is considered non-protective. This longstanding convention has been challenged with recent evidences of increased susceptibility of hosts with compromised AMI and monoclonal antibodies conferring passive protection against TB and other intracellular pathogens. Therefore, novel approaches toward vaccine development include strategies aiming at induction of humoral response along with CMI. This necessitates the identification of mycobacterial proteins with properties of immunomodulation and strong immunogenicity. In this study, we determined the immunogenic potential of M. tuberculosis Zinc metalloprotease-1 (Zmp1), a secretory protein essential for intracellular survival and pathogenesis of M. tuberculosis. We observed that Zmp1 was secreted by in vitro grown M. tuberculosis under granuloma-like stress conditions (acidic, oxidative, iron deficiency, and nutrient deprivation) and generated Th2 cytokine microenvironment upon exogenous treatment of peripheral blood mononulear cells PBMCs with recombinant Zmp1 (rZmp1). This was supported by recording specific and robust humoral response in TB patients in a cohort of 295. The anti-Zmp1 titers were significantly higher in TB patients (n = 121) as against healthy control (n = 62), household contacts (n = 89) and non-specific infection controls (n = 23). A significant observation of the study is the presence of equally high titers of anti-Zmp1 antibodies in a range of patients with high bacilli load (sputum bacilli load of 300+ per mL) to paucibacillary smear-negative pulmonary tuberculosis (PTB) cases. This clearly indicated the potential of Zmp1 to evoke an effective humoral response independent of mycobacterial load. Such mycobacterial proteins can be explored as antigen candidates for prime-boost vaccination strategies or extrapolated as markers for disease detection and progression.

Circulating Interferon-Gamma Levels Are Associated with Low Body Weight in Newly Diagnosed Kenyan Non-Substance Using Tuberculosis Individuals

Although interferon-gamma, interleukin-10, and adiponectin are key immunopathogenesis mediators of tuberculosis, their association with clinical manifestations of early stage disease is inconclusive. We determined interferon-gamma, interleukin-10, and adiponectin levels in clinically and phenotypically well-characterised non-substance using new pulmonary tuberculosis patients (n = 13) and controls (n = 14) from Kenya. Interferon-gamma levels (P < 0.0001) and interferon-gamma to interleukin-10 (P < 0.001) and interferon-gamma to adiponectin (P = 0.027) ratios were elevated in tuberculosis cases. Correlation analyses in tuberculosis cases showed associations of interferon-gamma levels with body weight (ρ = -0.849; P < 0.0001), body mass index (ρ = 0.664; P = 0.013), hip girth (ρ = -0.579; P = 0.038), and plateletcrit (ρ = 0.605; P = 0.028); interferon-gamma to interleukin-10 ratio with diastolic pressure (ρ = -0.729; P = 0.005); and interferon-gamma to adiponectin ratio with body weight (ρ = -0.560; P = 0.047), body mass index (ρ = -0.604; P = 0.029), and plateletcrit (ρ = 0.793; P = 0.001). Taken together, our results suggest mild-inflammation in early stage infection characterised by upregulation of circulating interferon-gamma production in newly infected TB patients.

Gene expression and TB pathogenesis in rhesus macaques: TR4, CD40, CD40L, FAS (CD95), and TNF are host genetic markers in peripheral blood mononuclear cells that are associated with severity of TB lesions

Tuberculosis (TB) pathologic lesions in rhesus macaques resemble those in humans. The expression levels of several host TB candidate genes in the peripheral blood mononuclear cells (PBMCs) of six rhesus macaques experimentally infected with Mycobacterium tuberculosis were quantified pre-infection and at several dates post-infection. Quantitative measures of TB histopathology in the lungs including: granuloma count, granuloma size, volume of granulomatous and non-granulomatous lesions, and direct bacterial load, were used as the outcomes of a multi-level Bayesian regression model in which expression levels of host genes at various dates were used as predictors. The results indicate that the expression levels of TR4, CD40, CD40L, FAS (CD95) and TNF in PBMC were associated with quantitative measures of the severity of TB histopathologic lesions in the lungs of the study animals. Moreover, no reliable association between the expression levels of IFNE in PBMCs and the severity of TB lesions in the lungs of the study animals was found. In conclusion, PBMC expression profiles derived from the above-listed host genes might be appropriate biomarkers for probabilistic diagnosis and/or prognosis of TB severity in rhesus macaques.

Cytokine and chemokine expression profiles in response to Mycobacterium tuberculosis stimulation are altered in HIV-infected compared to HIV-uninfected subjects with active tuberculosis

Mycobacterium tuberculosis (Mtb) infects nearly 2 million people annually and is the most common cause of death in HIV-infected individuals. Tuberculosis (TB) diagnostics cater to HIV-uninfected individuals in non-endemic countries, are expensive, slow, and lack sensitivity for those most affected. Patterns of soluble immune markers from Mtb-stimulated immune cells are not well defined in HIV co-infection. We assessed immune differences between HIV-infected and HIV-uninfected individuals with active TB utilizing IFNγ-based QuantiFERON®-TB Gold In-Tube (QFT) testing in Nairobi, Kenya. Excess QFT supernatants were used to measure cytokine and chemokine responses by a 17-plex bead array. Mtb/HIV co-infected participants were significantly less likely to be QFT+ (47.2% versus 84.2% in the HIV-uninfected group), and demonstrated lower expression of all cytokines except for IFNα2. Receiver operator characteristic analyses identified IL-1α as a potential marker of co-infection. Among HIV-infected individuals, CD4+ T cell count correlated weakly with the expression of several analytes. Co-expression analysis highlighted differences in immune profiles between the groups. These data suggest that there is a unique and detectable Mtb-specific immune response in co-infection. A better understanding of Mtb immunology can translate into much needed immunodiagnostics with enhanced sensitivity in HIV-infected individuals, facilitating their opportunity to obtain live-saving treatment.

Mycobacterial and HIV infections up-regulated human zinc finger protein 134, a novel positive regulator of HIV-1 LTR activity and viral propagation

BACKGROUND

Concurrent occurrence of HIV and Tuberculosis (TB) infections influence the cellular environment of the host for synergistic existence. An elementary approach to understand such coalition at the molecular level is to understand the interactions of the host and the viral factors that subsequently effect viral replication. Long terminal repeats (LTR) of HIV genome serve as a template for binding trans-acting viral and cellular factors that regulate its transcriptional activity, thereby, deciding the fate of HIV pathogenesis, making it an ideal system to explore the interplay between HIV and the host.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, using biotinylated full length HIV-1 LTR sequence as bait followed by MALDI analyses, we identified and further characterized human-Zinc-finger-protein-134 (hZNF-134) as a novel positive regulator of HIV-1 that promoted LTR-driven transcription and viral production. Over-expression of hZNF-134 promoted LTR driven luciferase activity and viral transcripts, resulting in increased virus production while siRNA mediated knockdown reduced both the viral transcripts and the viral titers, establishing hZNF-134 as a positive effector of HIV-1. HIV, Mycobacteria and HIV-TB co-infections increased hZNF-134 expressions in PBMCs, the impact being highest by mycobacteria. Corroborating these observations, primary TB patients (n = 22) recorded extraordinarily high transcript levels of hZNF-134 as compared to healthy controls (n = 16).

CONCLUSIONS/SIGNIFICANCE

With these observations, it was concluded that hZNF-134, which promoted HIV-1 LTR activity acted as a positive regulator of HIV propagation in human host. High titers of hZNF-134 transcripts in TB patients suggest that up-regulation of such positive effectors of HIV-1 upon mycobacterial infection can be yet another mechanism by which mycobacteria assists HIV-1 propagation during HIV-TB co-infections. hZNF-134, an uncharacterized host protein, thus assumes a novel regulatory role during HIV-host interactions. Our study provides new insights into the emerging role of zinc finger proteins in HIV-1 pathogenesis.

Human protein Staufen-2 promotes HIV-1 proliferation by positively regulating RNA export activity of viral protein Rev

Background

The export of intron containing viral RNAs from the nucleus to the cytoplasm is an essential step in the life cycle of Human Immunodeficiency Virus-1 (HIV-1). As the eukaryotic system does not permit the transport of intron containing RNA out of the nucleus, HIV-1 makes a regulatory protein, Rev, that mediates the transportation of unspliced and partially spliced viral mRNA from the nucleus to the cytoplasm, thereby playing a decisive role in the generation of new infectious virus particles. Therefore, the host factors modulating the RNA export activity of Rev can be major determinants of virus production in an infected cell.

Results

In this study, human Staufen-2 (hStau-2) was identified as a host factor interacting with HIV-1 Rev through affinity chromatography followed by MALDI analyses. Our experiments involving transient expressions, siRNA mediated knockdowns and infection assays conclusively established that hStau-2 is a positive regulator of HIV-1 pathogenesis. We demonstrated that Rev-hStau-2 interactions positively regulated the RNA export activity of Rev and promoted progeny virus synthesis. The Rev-hStau-2 interaction was independent of RNA despite both being RNA binding proteins. hStau-2 mutant, with mutations at Q314R-A318F-K319E, deficient of binding Rev, failed to promote hStau-2 dependent Rev activity and viral production, validating the essentiality of this protein-protein interaction. The expression of this positive regulator was elevated upon HIV-1 infection in both human T-lymphocyte and astrocyte cell lines.

Conclusions

With this study, we establish that human Staufen-2, a host factor which is up-regulated upon HIV-1 infection, interacts with HIV-1 Rev, thereby promoting its RNA export activity and progeny virus formation. Altogether, our study provides new insights into the emerging role of the Staufen family of mRNA transporters in host-pathogen interaction and supports the notion that obliterating interactions between viral and host proteins that positively regulate HIV-1 proliferation can significantly contribute to anti-retroviral treatments.

Impact of viral factors on subcellular distribution and RNA export activity of HIV-1 rev in astrocytes 1321N1

CNS associated cells are permissive to HIV-1 infection, but poor in virus production due to attenuated Rev activity. The temporal and the spatial distribution of Rev in human astrocyte 1321N1 and glioblastoma GO-G-CCM were monitored for explaining the reduced Rev activity and low viral production during HIV-1 infection. Rev remained localized to the nuclei of these cells upon infection, attenuating its export activity, as manifested by low copy number of RRE-containing viral-mRNA in the cytoplasm of these cells. In contrast to infection, when Rev alone was transiently expressed, it localized in the cytoplasm of 1321N1. The localization changed to the nucleus when Rev was expressed in the presence of other viral proteins through pro-viral DNA pNL4-3. This study, for the first time, revealed the impact of other HIV-1 proteins apart from host factors in regulating the subcellular localization of Rev in astrocytes and hence the fate of HIV-1 infection in these cells.