Human immunodeficiency virus (HIV) infection leads to severe CD4+ T-cell depletion in gut-associated lymphoid tissue (GALT) that persists despite the initiation of highly active antiretroviral therapy (HAART). It is not known whether restoration of gut mucosal CD4+ T cells and their functions is feasible during therapy and how that relates to immune correlates and viral reservoirs. Intestinal biopsies and peripheral blood samples from HIV-infected patients who were either HAART naive or on long-term HAART were evaluated. Our data demonstrated that gut CD4+ T-cell restoration ranged from modest (<50%) to high (>50%), compared with uninfected controls. Despite persistent CD4+ T-cell proviral burden and residual immune activation in GALT during HAART, effective CD4+ T-cell restoration (>50%) was achieved, which was associated with enhanced Th17 CD4+ T-cell accumulation and polyfunctional anti-HIV cellular responses. Our findings suggest that a threshold of>50% CD4+ T-cell restoration may be sufficient for polyfunctional HIV-specific T cells with implications in the evaluation of vaccines and therapeutics.

The NF-κB protein RelB controls dendritic cell (DC) maturation and may be targeted therapeutically to manipulate T cell responses in disease. Here we report that RelB promoted DC activation not as the expected RelB-p52 effector of the non-canonical NF-κB pathway, but as a RelB-p50 dimer regulated by canonical IκBs, IκBα and IκBε. IκB control of RelB minimized spontaneous maturation but enabled rapid pathogen-responsive maturation. Computational modeling of the NF-κB signaling module identified control points of this unexpected cell-type-specific regulation. Fibroblasts that were engineered accordingly showed DC-like RelB control. Canonical pathway control of RelB regulated pathogen-responsive gene expression programs. This work illustrates the potential utility of systems analyses in guiding the development of combination therapeutics for modulating DC-dependent T cell responses.

Chronic viral infections represent a unique challenge to the infected host. Persistently replicating viruses outcompete or subvert the initial antiviral response, allowing the establishment of chronic infections that result in continuous stimulation of both the innate and adaptive immune compartments. This causes a profound reprogramming of the host immune system, including attenuation and persistent low levels of type I interferons, progressive loss (or exhaustion) of CD8+ T cell functions, and specialization of CD4+ T cells to produce interleukin-21 and promote antibody-mediated immunity and immune regulation. Epigenetic, transcriptional, posttranscriptional, and metabolic changes underlie this adaptation or recalibration of immune cells to the emerging new environment in order to strike an often imperfect balance between the host and the infectious pathogen. In this review we discuss the common immunological hallmarks observed across a range of different persistently replicating viruses and host species, the underlying molecular mechanisms, and the biological and clinical implications.

Cytokines are produced by immune cells in response to viral or bacterial pathogens and therefore have significant diagnostic value. The goal of the present study was to develop a miniature device for detection of interleukin (IL)-2 and interferon (IFN)-gamma cytokines secreted by a small population of CD4 and CD8 T-cells. Microarrays of T-cell- and cytokine-specific Ab spots were printed onto poly(ethylene glycol) (PEG) hydrogel-coated glass slides and enclosed inside a microfluidic device, creating a miniature ( approximately 3 microL) immunoreaction chamber. Introduction of the red blood cell (RBC) depleted whole human blood into the microfluidic device followed by washing at a pre-defined shear stress resulted in isolation of pure CD4 and CD8 T-cells on their respective Ab spots. Importantly, the cells became localized next to anti-IL-2 and -IFN-gamma Ab spots. Mitogenic activation of the captured T-cells was followed by immunofluorescent staining (all steps carried out inside a microfluidic device), revealing concentration gradients of surface-bound cytokine molecules. A microarray scanner was then used to quantify the concentration of IFN-gamma and IL-2 near CD4 and CD8 T-cells. This study represents one of the first demonstrations of a microdevice for capturing desired T-cell subsets from a small blood volume and determining, on-chip, cytokine profiles of the isolated cells. Such a microdevice is envisioned as an immunology tool for multi-parametric analysis of T-cell function with direct applications in diagnosis/monitoring of HIV and other infectious diseases.

BackgroundWomen and men have diverse responses to many infectious diseases. These differences are amplified following menopause. However, despite extensive information regarding the effects of sex hormones on immune cells, our knowledge is limited regarding the effects of sex and gender on the function of the mucosal immune system. Sex differences also manifest in the prevalence of gut associated inflammatory and autoimmune disorders, including Crohn’s disease, ulcerative colitis and Celiac disease. It is thus hypothesized that a baseline sex-associated difference in immune activation may predispose women to inflammation-associated disease.MethodsPeripheral blood samples and small intestinal biopsies were obtained from 34 healthy men and women. Immunophenotypic analysis of isolated lymphocytes was performed by flow cytometry. Oligonucleotide analysis was used to study the transcriptional profile in the gut mucosal microenvironment while real-time PCR analysis was utilized to identify differential gene expression in isolated CD4+ T cells. Transcriptional analysis was confirmed by protein expression levels for genes of interest using fluorescent immunohistochemistry. Data was analyzed using the GraphPad software package.ResultsWomen had higher levels of immune activation and inflammation-associated gene expression in gut mucosal samples. CD4+ and CD8+ T cells had a significantly higher level of immune activation-associated phenotype in peripheral blood as well as in gut associated lymphoid tissue along with higher levels of proliferating T cells. CD4+ T cells that showed upregulation of IL1β as well as the TH17 pathway-associated genes contributed a large part of the inflammatory profile.ConclusionIn this study, we demonstrated an upregulation in gene expression related to immune function in the gut microenvironment of women compared to men, in the absence of disease or pathology. Upon closer investigation, CD4+ T cell activation levels were higher in the LPLs in women than in men. Sex differences in the mucosal immune system may predispose women to inflammation-associated diseases that are exacerbated following menopause. Our study highlights the need for more detailed analysis of the effects of sex differences in immune responses at mucosal effector sites.