Differential Expression of Activation Markers by Mycobacterium tuberculosis-specific CD4+ T Cell Distinguishes Extrapulmonary From Pulmonary Tuberculosis and Latent Infection.

Background: Diagnosis of active tuberculosis (ATB) currently relies on detection of Mycobacterium tuberculosis (Mtb). Identifying patients with extrapulmonary TB (EPTB) remains challenging because microbiological confirmation is often not possible. Highly accurate blood-based tests could improve diagnosis of both EPTB and pulmonary TB (PTB) and timely initiation of anti-TB therapy.

High Frequencies of Caspase-3 Expressing -Specific CD4 T Cells Are Associated With Active Tuberculosis.

Antigen-specific CD4 T cell responses to (Mtb) infection are important for host defense against tuberculosis (TB). However, Mtb-specific IFN-γ-producing T cells do not distinguish active tuberculosis (ATB) patients from individuals with asymptomatic latent Mtb infection (LTBI). We reasoned that the immune phenotype of Mtb-specific IFN-γCD4 T cells could provide an indirect gauge of Mtb antigen load within individuals.

CD4 Foxp3 T cells promote aberrant immunoglobulin G production and maintain CD8 T-cell suppression during chronic liver disease.

Unlabelled: Persistent hepatotropic viral infections are a common etiologic agent of chronic liver disease. Unresolved infection can be attributed to nonfunctional intrahepatic CD8+ T-cell responses. In light of dampened CD8 T-cell responses, liver disease often manifests systemically as immunoglobulin (Ig)-related syndromes due to aberrant B-cell functions.

INTIMATE PARTNER VIOLENCE IS ASSOCIATED WITH INCREASED CD4 T-CELL ACTIVATION AMONG HIV-NEGATIVE HIGH-RISK WOMEN.

Background: Biological pathways mediating the link between intimate partner violence (IPV) and increased HIV risk remain unexplored. We hypothesized that IPV-induced stress negatively affects HIV systemic immune defenses and aimed to evaluate whether IPV was associated with immune profiles linked to HIV susceptibility: CD4 activation and diminished regulatory T-cell (Treg) frequency.

Methods: Seventy-five HIV-negative high-risk women were surveyed regarding their IPV experience.

Induction of Th1-Biased T Follicular Helper (Tfh) Cells in Lymphoid Tissues during Chronic Simian Immunodeficiency Virus Infection Defines Functionally Distinct Germinal Center Tfh Cells.

Chronic HIV infection is associated with accumulation of germinal center (GC) T follicular helper (Tfh) cells in the lymphoid tissue. The GC Tfh cells can be heterogeneous based on the expression of chemokine receptors associated with T helper lineages, such as CXCR3 (Th1), CCR4 (Th2), and CCR6 (Th17). However, the heterogeneous nature of GC Tfh cells in the lymphoid tissue and its association with viral persistence and Ab production during chronic SIV/HIV infection are not known.

Humoral and Cell-Mediated Immune Responses to Alternate Booster Schedules of Anthrax Vaccine Adsorbed in Humans.

Protective antigen (PA)-specific antibody and cell-mediated immune (CMI) responses to annual and alternate booster schedules of anthrax vaccine adsorbed (AVA; BioThrax) were characterized in humans over 43 months. Study participants received 1 of 6 vaccination schedules: a 3-dose intramuscular (IM) priming series (0, 1, and 6 months) with a single booster at 42 months (4-IM); 3-dose IM priming with boosters at 18 and 42 months (5-IM); 3-dose IM priming with boosters at 12, 18, 30, and 42 months (7-IM); the 1970 licensed priming series of 6 doses (0, 0.5, 1, 6, 12, and 18 months) and two annual boosters (30 and 42 months) administered either subcutaneously (SQ) (8-SQ) or IM (8-IM); or saline placebo control at all eight time points.

Biomarkers on patient T cells diagnose active tuberculosis and monitor treatment response.

Background: The identification and treatment of individuals with tuberculosis (TB) is a global public health priority. Accurate diagnosis of pulmonary active TB (ATB) disease remains challenging and relies on extensive medical evaluation and detection of Mycobacterium tuberculosis (Mtb) in the patient's sputum. Further, the response to treatment is monitored by sputum culture conversion, which takes several weeks for results.

Systems biological analyses reveal the hepatitis C virus (HCV)-specific regulation of hematopoietic development.

Unlabelled: Chronic liver disease is characterized by the liver enrichment of myeloid dendritic cells (DCs). To assess the role of disease on myelopoiesis, we utilized a systems biology approach to study development in liver-resident cells expressing stem cell marker CD34. In patients with endstage liver disease, liver CD34+ cells were comprised of two subsets, designated CD34+CD146+ and CD34+CD146-, and hematopoietic function was restricted to CD34+CD146- cells.

Impaired degranulation and proliferative capacity of Mycobacterium tuberculosis-specific CD8+ T cells in HIV-infected individuals with latent tuberculosis.

Human immunodeficiency virus (HIV)-infected individuals with latent Mycobacterium tuberculosis infection have substantially higher rates of progression to active tuberculosis than HIV-uninfected individuals with latent tuberculosis. To explore HIV-induced deficits in M. tuberculosis-specific CD8+ T-cell functions, we compared interferon γ production, degranulation, and proliferation of CD8+ T cells in response to M.

Role of intestinal mucosal integrity in HIV transmission to infants through breast-feeding: the BAN study.

Background: Increased intestinal permeability may be one of the mechanisms of transmission of human immunodeficiency virus (HIV) to infants through breast-feeding. Intestinal permeability correlates with microbial translocation, which can be measured through quantification of bacterial lipopolysaccharide (LPS).

Methods: We evaluated levels of plasma LPS (by the Limulus amebocyte lysate assay) and immune activation markers in serial specimens from infants exposed to but uninfected with HIV and infants infected with HIV from the Breastfeeding, Antiretrovirals, and Nutrition (BAN) study.

A three-dose intramuscular injection schedule of anthrax vaccine adsorbed generates sustained humoral and cellular immune responses to protective antigen and provides long-term protection against inhalation anthrax in rhesus macaques.

A 3-dose (0, 1, and 6 months) intramuscular (3-IM) priming series of a human dose (HuAVA) and dilutions of up to 1:10 of anthrax vaccine adsorbed (AVA) provided statistically significant levels of protection (60 to 100%) against inhalation anthrax for up to 4 years in rhesus macaques. Serum anti-protective antigen (anti-PA) IgG and lethal toxin neutralization activity (TNA) were detectable following a single injection of HuAVA or 1:5 AVA or following two injections of diluted vaccine (1:10, 1:20, or 1:40 AVA). Anti-PA and TNA were highly correlated (overall r(2) = 0.

Distinct effector memory CD4+ T cell signatures in latent Mycobacterium tuberculosis infection, BCG vaccination and clinically resolved tuberculosis.

Two billion people worldwide are estimated to be latently infected with Mycobacterium tuberculosis (Mtb) and are at risk for developing active tuberculosis since Mtb can reactivate to cause TB disease in immune-compromised hosts. Individuals with latent Mtb infection (LTBI) and BCG-vaccinated individuals who are uninfected with Mtb, harbor antigen-specific memory CD4(+) T cells. However, the differences between long-lived memory CD4(+) T cells induced by latent Mtb infection (LTBI) versus BCG vaccination are unclear.

Use of replication restricted recombinant vesicular stomatitis virus vectors for detection of antigen-specific T cells.

Detection of antigen-specific T cells at the single-cell level by ELISpot or flow cytometry techniques employing intracellular cytokine staining (ICS) is now an indispensable tool in many areas of immunology. When precisely mapped, optimal MHC-binding peptide epitopes are unknown, these assays use antigen in a variety of forms, including recombinant proteins, overlapping peptide sets representing one or more target protein sequences, microbial lysates, lysates of microbially-infected cells, or gene delivery vectors such as DNA expression plasmids or recombinant vaccinia or adenoviruses expressing a target protein of interest. Here we introduce replication-restricted, recombinant vesicular stomatitis virus (VSV) vectors as a safe, easy to produce, simple to use, and highly effective vector for genetic antigen delivery for the detection of human antigen-specific helper and cytotoxic T cells.

Phenotype, function, and gene expression profiles of programmed death-1(hi) CD8 T cells in healthy human adults.

T cell dysfunction is an important feature of many chronic viral infections. In particular, it was shown that programmed death-1 (PD-1) regulates T cell dysfunction during chronic lymphocytic choriomeningitis virus infection in mice, and PD-1(hi) cells exhibit an intense exhausted gene signature. These findings were extended to human chronic infections such as HIV, hepatitis C virus, and hepatitis B virus.

Prior exposure to an attenuated Listeria vaccine does not reduce immunogenicity: pre-clinical assessment of the efficacy of a Listeria vaccine in the induction of immune responses against HIV.

Background: We have evaluated an attenuated Listeria monocytogenes (Lm) candidate vaccine vector in nonhuman primates using a delivery regimen relying solely on oral vaccination. We sought to determine the impact of prior Lm vector exposure on the development of new immune responses against HIV antigens.

Findings: Two groups of rhesus macaques one Lm naive, the other having documented prior Lm vector exposures, were evaluated in response to oral inoculations of the same vector expressing recombinant HIV-1 Gag protein.

Transient CD86 expression on hepatitis C virus-specific CD8+ T cells in acute infection is linked to sufficient IL-2 signaling.

Costimulatory signals via B7/CD28 family molecules (signal 2) are critical for effective adaptive CD8(+) T cell immune responses. In addition to costimulatory signals, B7/CD28 family coinhibitory receptor/ligands that modulate immune responses have been identified. In acute hepatitis C virus (HCV) infection, programmed death receptor 1, an inhibitory receptor in the CD28 family, is highly expressed on virus-specific CD8(+) T cells, yet vigorous immune responses often develop.

Impaired hepatitis C virus (HCV)-specific effector CD8+ T cells undergo massive apoptosis in the peripheral blood during acute HCV infection and in the liver during the chronic phase of infection.

A majority of patients infected with hepatitis C virus (HCV) do not sustain an effective T-cell response, and viremia persists. The mechanism leading to failure of the HCV-specific CD8(+) T-cell response in patients developing chronic infection is unclear. We investigated apoptosis susceptibility of HCV-specific CD8(+) T cells during the acute and chronic stages of infection.

Differential expression of CD26 on virus-specific CD8(+) T cells during active, latent and resolved infection.

The hallmark of effective establishment of immune memory is the long-term memory cell that persists in the absence of antigen. To explore its characteristics, we investigated the differences between a resolved successful immune response, such as after influenza (flu) vaccination, and the state of chronic infection with persistent antigen, such as with cytomegalovirus (CMV), Epstein-Barr virus (EBV) or human immunodeficiency virus (HIV), which leads to defective T-cell memory. Immunophenotypic analyses using multi-parameter flow cytometry and tetramer technology identified a unique pattern of CD26(high) expression among influenza-specific CD8(+) T cells, but not among CD8(+) T cells specific for CMV, EBV (three different epitopes) or HIV.

Postnatal stem/progenitor cells derived from the dental pulp of adult chimpanzee.

Background: Chimpanzee dental pulp stem/stromal cells (ChDPSCs) are very similar to human bone marrow derived mesenchymal stem/stromal cells (hBMSCs) as demonstrated by the expression pattern of cell surface markers and their multipotent differentiation capability.

Results: ChDPSCs were isolated from an incisor and a canine of a forty-seven year old female chimpanzee. A homogenous population of ChDPSCs was established in early culture at a high proliferation rate and verified by the expression pattern of thirteen cell surface markers.

Virally induced CD4+ T cell depletion is not sufficient to induce AIDS in a natural host.

Peripheral blood CD4+ T cell counts are a key measure for assessing disease progression and need for antiretroviral therapy in HIV-infected patients. More recently, studies have demonstrated a dramatic depletion of mucosal CD4+ T cells during acute infection that is maintained during chronic pathogenic HIV as well as SIV infection. A different clinical disease course is observed during the infection of natural hosts of SIV infection, such as sooty mangabeys (Cercocebus atys), which typically do not progress to AIDS.

Breast milk CD4+ T cells express high levels of C chemokine receptor 5 and CXC chemokine receptor 4 and are preserved in HIV-infected mothers receiving highly active antiretroviral therapy.

Background: Transmission of human immunodeficiency virus (HIV) to the infant through breast-feeding is a major problem worldwide; however, the biological circumstances of such transmission remain unclear. Little characterization of breast milk CD4(+) T lymphocytes has been done so far.

Methods: We performed a detailed immunophenotypic analysis of T lymphocytes in the breast milk, compared with the blood, of HIV-uninfected (n=9) and HIV-infected (n=10) women receiving highly active antiretroviral therapy, by use of multiparameter flow cytometry.

Antigen-specific CD4+ T cells recognize epitopes of protective antigen following vaccination with an anthrax vaccine.

Detection of antigen-specific CD4+ T cells is facilitated by the use of fluorescently labeled soluble peptide-major histocompatibility complex (MHC) multimers which mirror the antigen specificity of T-cell receptor recognition. We have used soluble peptide-MHC class II tetramers containing peptides from the protective antigen (PA) of Bacillus anthracis to detect circulating T cells in peripheral blood of subjects vaccinated with an anthrax vaccine. PA-specific HLA class II-restricted T lymphocytes were isolated which displayed both TH1- and TH2-like characteristics, indicating heterogeneity of the lymphocyte lineage within the CD4+ response.

Liver-infiltrating lymphocytes in chronic human hepatitis C virus infection display an exhausted phenotype with high levels of PD-1 and low levels of CD127 expression.

The majority of people infected with hepatitis C virus (HCV) fail to generate or maintain a T-cell response effective for viral clearance. Evidence from murine chronic viral infections shows that expression of the coinhibitory molecule PD-1 predicts CD8+ antiviral T-cell exhaustion and may contribute to inadequate pathogen control. To investigate whether human CD8+ T cells express PD-1 and demonstrate a dysfunctional phenotype during chronic HCV infection, peripheral and intrahepatic HCV-specific CD8+ T cells were examined.