Sodium Benzoate, a Food Additive and a Metabolite of Cinnamon, Enriches Regulatory T Cells via STAT6-Mediated Upregulation of TGF-ß.

Upregulation and/or maintenance of regulatory T cells (Tregs) during autoimmune insults may have therapeutic efficacy in autoimmune diseases. Earlier we have reported that sodium benzoate (NaB), a metabolite of cinnamon and a Food and Drug Administration-approved drug against urea cycle disorders, upregulates Tregs and protects mice from experimental allergic encephalomyelitis, an animal model of multiple sclerosis. However, mechanisms by which NaB increases Tregs are poorly understood. Because TGF-ß is an important inducer of Tregs, we examined the effect of NaB on the status of TGF-ß. In this study, we demonstrated that NaB induced the expression of TGF-ß mRNA and protein in normal as well as proteolipid protein-primed splenocytes. The presence of a consensus STAT6 binding site in the promoter of the TGF-ß gene, activation of STAT6 in splenocytes by NaB, recruitment of STAT6 to the TGF-ß promoter by NaB, and abrogation of NaB-induced expression of TGF-ß in splenocytes by small interfering RNA knockdown of STAT6 suggest that NaB induces the expression of TGF-ß via activation of STAT6. Furthermore, we demonstrated that blocking of TGF-ß by neutralizing Abs abrogated NaB-mediated protection of Tregs and experimental allergic encephalomyelitis. These studies identify a new function of NaB in upregulating TGF-ß via activation of STAT6, which may be beneficial in MS patients.

Modulation of TIM-3 expression on NK and T cell subsets in HIV immunological non-responders.

Highly active antiretroviral therapy (HAART) for the treatment of HIV infection sustains viral suppression and increases CD4(+) T cells in HIV patients. However, in 10-25% of subjects, known as immunological non-responders (INRs), HAART does not increase CD4 count. We investigated a potential role for galectin-9 and TIM-3 in INRs as galectin-9 and TIM-3 have been described to modulate NK and T cell function. PBMCs were isolated from healthy controls, HIV immunological responders (IRs, >350CD4(+) cells/mm(3)) and HIV INRs (<350CD4(+) cells/mm(3)) and TIM-3 and galectin-9 expressions on NK cell subsets and CD4(+) T cells were assessed. HIV INRs and HIV IRs showed increased galectin-9 expression on CD16(-)CD56(bright) and CD16(+)CD56(+) NK cells and CD4(+) T cells. Only HIV INRs showed a reduced frequency of TIM-3-expressing CD16(+)CD56(+), CD16(+)CD56(-) and CD4(+) cells, which correlated with low peripheral CD4 counts. These data suggest that TIM-3 expression may be characteristic for HIV INRs.

Virological and immunological characteristics of human cytomegalovirus infection associated with Alzheimer disease.

Serum, cerebrospinal fluid (CSF), and cryopreserved lymphocytes from subjects in the Rush Alzheimer's Disease Center Religious Orders Study were analyzed for associations between cytomegalovirus (CMV) infection and clinical and pathological markers of Alzheimer disease. CMV antibody levels were associated with neurofibrillary tangles (NFTs). CSF interferon γ was only detected in seropositive subjects and was significantly associated with NFTs. The percentage of senescent T cells (CD4+ or CD8+CD28-CD57+) was significantly higher for CMV-seropositive as compared to CMV-seronegative subjects and was marginally associated with the pathologic diagnosis of Alzheimer disease (CD4+) or amyloid-ß (CD8+). Immunocytochemical analysis showed induction of amyloid-ß in human foreskin fibroblasts (HFFs) infected with each of 3 clinical CMV strains. In the same subjects, there was no association of herpes simplex virus type 1 (HSV-1) antibody levels with CMV antibody levels or clinical or pathological markers of Alzheimer disease. HSV-1 infection of HFFs did not induce amyloid-ß. These data support an association between CMV and the development of Alzheimer disease.

Potent HIV-specific responses are enriched in a unique subset of CD8+ T cells that coexpresses CD4 on its surface.

In humans, approximately 3% of peripheral CD8+ T cells coexpress CD4 dimly on their surface and hence are designated as CD4(dim)CD8(bright) T cells. We evaluated the contribution of this CD4(dim)CD8(bright) T-cell population to anti-HIV immunity. We demonstrate that CD4(dim)CD8(bright) T cells generate greater than 55% of CD8+ T-cell antigen recognition and effector response to HIV, as evaluated by multiple parameters for assessing T-cell antiviral immunity, including HIV tetramer recognition, cytokine production, and cytolytic potential. Inhibition of major histocompatibility class II (MHC-II) on target cells or CD4 on CD4(dim)CD8(bright) T cells diminishes their anti-HIV responses, suggesting that CD4 on effector cells and MHC-II on target cells provides an additional arm of contact between effector and target cells which is critical to CD4(dim)CD8(bright) T-cell function. CD4(dim)CD8(bright) T cells also exhibit features that are indicative of central memory T cells. Finally, CD4(dim)CD8(bright) T cells are elevated in blood of HIV+ long-term nonprogressors in comparison to HIV- donors. Collectively, our findings show that CD4(dim)CD8(bright) T cells designate an enriched antiviral subpopulation of CD8+ T cells that should be targeted for therapeutic intervention or evaluation of vaccine efficacy.

Upregulated IL-32 Expression And Reduced Gut Short Chain Fatty Acid Caproic Acid in People Living With HIV With Subclinical Atherosclerosis.

Despite the success of antiretroviral therapy (ART), people living with HIV (PLWH) are still at higher risk for cardiovascular diseases (CVDs) that are mediated by chronic inflammation. Identification of novel inflammatory mediators with the inherent potential to be used as CVD biomarkers and also as therapeutic targets is critically needed for better risk stratification and disease management in PLWH. Here, we investigated the expression and potential role of the multi-isoform proinflammatory cytokine IL-32 in subclinical atherosclerosis in PLWH (n=49 with subclinical atherosclerosis and n=30 without) and HIV- controls (n=25 with subclinical atherosclerosis and n=24 without). While expression of all tested IL-32 isoforms (α, ß, γ, D, ϵ, and θ) was significantly higher in peripheral blood from PLWH compared to HIV- controls, IL-32D and IL-32θ isoforms were further upregulated in HIV+ individuals with coronary artery atherosclerosis compared to their counterparts without. Upregulation of these two isoforms was associated with increased plasma levels of IL-18 and IL-1ß and downregulation of the atheroprotective protein TRAIL, which together composed a unique atherosclerotic inflammatory signature specific for PLWH compared to HIV- controls. Logistic regression analysis demonstrated that modulation of these inflammatory variables was independent of age, smoking, and statin treatment. Furthermore, our in vitro functional data linked IL-32 to macrophage activation and production of IL-18 and downregulation of TRAIL, a mechanism previously shown to be associated with impaired cholesterol metabolism and atherosclerosis. Finally, increased expression of IL-32 isoforms in PLWH with subclinical atherosclerosis was associated with altered gut microbiome (increased pathogenic bacteria; Rothia and Eggerthella species) and lower abundance of the gut metabolite short-chain fatty acid (SCFA) caproic acid, measured in fecal samples from the study participants. Importantly, caproic acid diminished the production of IL-32, IL-18, and IL-1ß in human PBMCs in response to bacterial LPS stimulation. In conclusion, our studies identified an HIV-specific atherosclerotic inflammatory signature including specific IL-32 isoforms, which is regulated by the SCFA caproic acid and that may lead to new potential therapies to prevent CVD in ART-treated PLWH.

Single center, open label dose escalating trial evaluating once weekly oral ixazomib in ART-suppressed, HIV positive adults and effects on HIV reservoir size in vivo.

BACKGROUND: Achieving a functional or sterilizing cure for HIV will require identification of therapeutic interventions that reduce HIV reservoir size in infected individuals. Proteasome inhibitors, such as ixazomib, impact multiple aspects of HIV biology including latency, transcription initiation, viral replication, and infected cell killing through the HIV protease - Casp8p41 pathway, resulting in latency reversal and reduced measures of HIV reservoir size ex vivo. METHODS: We conducted a phase 1b/2a dose escalating, open label trial of weekly oral ixazomib for 24 weeks in antiretroviral (ART)-suppressed, HIV positive adults (NCT02946047). The study was conducted from March 2017 to August 2019 at two tertiary referral centers in the United States. The primary outcomes were safety and tolerability of oral ixazomib. Secondary outcomes included changes in immunologic markers and estimates of HIV reservoir size after ixazomib treatment. FINDINGS: Sixteen participants completed the study. Ixazomib up to 4mg weekly was safe and well-tolerated, yielding no treatment-emergent events above grade 1. In exploratory analyses, ixazomib treatment was associated with detectable viremia that was below the lower limit of quantification (LLQ) in 9 participants, and viremia that was above LLQ in 4 of 16 participants. While treatment was associated with reduced CD4 counts [baseline 783 cells/ mm3 vs. week-24 724 cells/ mm3 p=0.003], there were no changes in markers of cellular activation, exhaustion or inflammation. Total HIV DNA and proviral sequencing were not altered by ixazomib treatment. Intact proviral DNA assay (IPDA) identified intact proviruses in 14 patients pre-treatment, and in 10/14 of those subjects post treatment values were reduced (P=0.068), allowing a calculated intact proviral half life of 0.6 years (95% CI 0.3, 2.5), compared to 7.1 years (95% CI 3.9, 18, p=0.004) in historical controls. Differentiation Quantitative Viral Outgrowth Assays (dQVOA) identified measurable proviruses in 15 subjects pre-treatment; post-treatment values were numerically reduced in 9, but overall differences were not significantly different. INTERPRETATION: Our study successfully met its primary endpoint of demonstrating the safety of ixazomib for 24 weeks in HIV infected persons. Exploratory analyses suggest that the effects observed ex vivo of latency reversal and reductions in HIV reservoir size, also occur in vivo. Future controlled studies of ixazomib are warranted. FUNDING: This study was funded by Millennium Pharmaceuticals Inc..; the Mayo Clinic Foundation; the National Institutes of Health, including the National Institute of Allergy and Infectious Diseases, Division of AIDS, the National Heart, Lung and Blood Institute, the National Institute of Diabetes and Digestive and Kidney Diseases, the National Institute of Neurological Disorders and Stroke, and the National Institute on Drug Abuse. Mayo Clinic also acknowledges generous funding support from Mr. Joseph T. and Mrs. Michele P. Betten.

Chloroquine modulates HIV-1-induced plasmacytoid dendritic cell alpha interferon: implication for T-cell activation.

Plasmacytoid dendritic cells (pDC) contribute to antiviral immunity mainly through recognition of microbial products and viruses via intracellular Toll-like receptor 7 (TLR7) or TLR9, resulting in the production of type I interferons (IFNs). Although interferons reduce the viral burden in the acute phase of infection, their role in the chronic phase is unclear. The presence of elevated plasma IFN-alpha levels in advanced HIV disease and its association with microbial translocation in chronic HIV infection lead us to hypothesize that IFN-alpha could contribute to immune activation. Blocking of IFN-alpha production using chloroquine, an endosomal inhibitor, was tested in a novel in vitro model system with the aim of characterizing the effects of chloroquine on HIV-1-mediated TLR signaling, IFN-alpha production, and T-cell activation. Our results indicate that chloroquine blocks TLR-mediated activation of pDC and MyD88 signaling, as shown by decreases in the levels of the downstream signaling molecules IRAK-4 and IRF-7 and by inhibition of IFN-alpha synthesis. Chloroquine decreased CD8 T-cell activation induced by aldrithiol-2-treated HIV-1 in peripheral blood mononuclear cell cultures. In addition to blocking pDC activation, chloroquine also blocked negative modulators of the T-cell response, such as indoleamine 2,3-dioxygenase (IDO) and programmed death ligand 1 (PDL-1). Our results indicate that TLR stimulation and production of IFN-alpha by pDC contribute to immune activation and that blocking of these pathways using chloroquine may interfere with events contributing to HIV pathogenesis. Our results suggests that a safe, well-tolerated drug such as chloroquine can be proposed as an adjuvant therapeutic candidate along with highly active antiretroviral therapy to control immune activation in HIV-1 infection.

The effect of aging on T-regulatory cell frequency in HIV infection.

T-regulatory cell (T-reg) frequency is increased in HIV infection and with aging. We evaluated the effect of age on total, memory and naïve T-reg percentages in untreated HIV infection. Older HIV(+) subjects had a total T-reg percent that is 2.8% (p=0.02) higher than among younger HIV(+), older HIV(-) and younger HIV(-) subjects. In HIV(+) subjects, the total T-reg percentage is inversely correlated with the lymphocyte proliferative responses to tetanus (r=-0.45, p=0.002) and Candida (r=-0.43, p=0.003) antigens. Similar correlations were seen between memory T-reg percentages and the lymphocyte proliferative response to tetanus and Candida in HIV(+) subjects. T-reg percentages did not correlate consistently with markers of immune activation. T-reg percentages are increased in the older HIV(+) population and may play a role in the accelerated disease progression seen in older HIV-infected persons.

Vitamin D does not modulate immune-mediated bone loss during ART initiation.

BACKGROUND: Vitamin D (VitD) and calcium (Ca) supplementation attenuates antiretroviral therapy (ART)-associated bone loss, but it is unclear whether this effect is mediated through immunomodulation. METHODS: In this exploratory analysis of A5280, a 48-week, randomized, double-blind, placebo-controlled study of VitD/Ca supplementation with ART initiation, we characterized lymphocyte phenotypes and receptor activator of nuclear factor kappa-B ligand (RANKL) expression by median fluorescence intensity (MFI) at baseline and 48 weeks. Changes were evaluated within and between treatment groups by Wilcoxon signed rank and rank sum tests, respectively. Spearman correlations estimated relationships between cellular phenotypes and bone mineral density (BMD). RESULTS: Of 165 participants enrolled, 138 had samples for cellular phenotypes (64 VitD/Ca, 74 placebo). Markers of CD4, CD8 activation (CD38+HLA-DR+) declined (all P<0.001), but did not differ between arms. There was no decline in either %T-cells (CD4 and CD8) expressing RANKL or expression of RANKL by MFI. CD4 and CD8 activation markers were not correlated with BMD at baseline (r<0.15 and P>0.09 for all), but greater declines in CD4 activation correlated with greater declines in hip and spine BMD in both arms (0.25 ≤r ≤0.37, all P<0.05). A greater decline in CD8 activation was correlated with greater declines in both hip and spine BMD in the placebo arm only (hip r=0.31, P=0.009; spine r=0.25, P=0.035). CONCLUSIONS: Reductions in T-cell activation are characteristic of ART initiation, but only correlated modestly with bone loss. VitD/Ca supplementation does not appear to mitigate bone loss through modulation of immune activation or expression of RANKL. TRIAL REGISTRATION NUMBER: NCT01403051.

Reactive oxygen species up-regulate CD11b in microglia via nitric oxide: Implications for neurodegenerative diseases.

Microglial activation is considered as a hallmark of several neurodegenerative disorders. During microglial activation, the expression of CD11b, the beta-integrin marker of microglia, is increased. However, the molecular mechanism behind increased microglial CD11b expression is poorly understood. The present study was undertaken to explore the role of reactive oxygen species (ROS) in the expression of CD11b in microglial cells. Bacterial lipopolysaccharide (LPS) stimulated the expression of CD11b in mouse BV-2 microglial cells and primary microglia, the effect that was blocked by antioxidants such as N-acetylcysteine (NAC) and pyrrolidine dithiocarbamate (PDTC). Furthermore, comicroinjection of either NAC or PDTC with LPS was also able to suppress LPS-stimulated expression of CD11b in striatum in vivo. Similarly, other neurotoxic molecules, such as interleukin-1beta (IL-1beta), IL-12 p40(2), fibrillar amyloid-beta (Abeta) peptides, HIV-1 gp120, and double-stranded RNA (poly(IC)), also stimulated the expression of CD11b in microglia through the involvement of ROS. Complete inhibition of LPS-stimulated expression of CD11b by catalase, induction of CD11b expression by H2O2 alone, and inhibition of superoxide-stimulated CD11b expression by catalase suggest that H2O2, but not superoxide, is in fact involved in the expression of CD11b. Interestingly, we also demonstrate that ROS stimulated the expression of CD11b after the induction of nitric oxide (NO) production and failed to stimulate CD11b when NO production was inhibited by either 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) or L-N6-(1-iminoethyl)-L-lysine (L-NIL). Taken together, these studies suggest that the up-regulation of CD11b in microglia is redox sensitive and that ROS up-regulates CD11b via NO.

PDL-1 upregulation on monocytes and T cells by HIV via type I interferon: restricted expression of type I interferon receptor by CCR5-expressing leukocytes.

The programmed death (PD)-1 interacts with its ligand (PDL-1) delivering a negative signal to T cells. During human immunodeficiency virus (HIV)-1 infection PD-1 and PDL-1 expressions are increased. Here we show that monocytes and CCR5(+) T cells of HIV-uninfected donors upregulated PDL-1 upon in vitro exposure to HIV. HIV-induced PDL-1 required interferon (IFN)-alpha, but not IFN-gamma, production. Inhibition of endocytosis, required for HIV-induced IFN-alpha production, prevented PDL-1 upregulation. IFN-alpha-inducing Toll-like receptor (TLR) agonists increased PDL-1 on monocytes and CCR5(+) T cells. CD80 and CD86 were also increased on monocytes and CCR5(+) T cells after HIV exposure, but only CD80 was IFN-alpha-dependent. IFN-alpha-receptor subunit 2 (IFNAR2), was expressed only by CCR5(+) T cells and monocytes, explaining why these leukocytes responded to HIV-induced IFN-alpha. Finally, T cell proliferation was improved by PDL-1 blockade in HIV-treated PBMC. In the setting of HIV infection, IFN-alpha may negatively affect T cell responses by inducing PDL-1.

Polymorphism rs1385129 Within Glut1 Gene SLC2A1 Is Linked to Poor CD4+ T Cell Recovery in Antiretroviral-Treated HIV+ Individuals.

Untreated HIV infection is associated with progressive CD4+ T cell depletion, which is generally recovered with combination antiretroviral therapy (cART). However, a significant proportion of cART-treated individuals have poor CD4+ T cell reconstitution. We investigated associations between HIV disease progression and CD4+ T cell glucose transporter-1 (Glut1) expression. We also investigated the association between these variables and specific single nucleotide polymorphisms (SNPs) within the Glut1 regulatory gene AKT (rs1130214, rs2494732, rs1130233, and rs3730358) and in the Glut1-expressing gene SLC2A1 (rs1385129 and rs841853) and antisense RNA 1 region SLC2A1-AS1 (rs710218). High CD4+Glut1+ T cell percentage is associated with rapid CD4+ T cell decline in HIV-positive treatment-naïve individuals and poor T cell recovery in HIV-positive individuals on cART. Evidence suggests that poor CD4+ T cell recovery in treated HIV-positive individuals is linked to the homozygous genotype (GG) associated with SLC2A1 SNP rs1385129 when compared to those with a recessive allele (GA/AA) (odds ratio = 4.67; P = 0.04). Furthermore, poor response to therapy is less likely among Australian participants when compared against American participants (odds ratio: 0.12; P = 0.01) despite there being no difference in prevalence of a specific genotype for any of the SNPs analyzed between nationalities. Finally, CD4+Glut1+ T cell percentage is elevated among those with a homozygous dominant genotype for SNPs rs1385129 (GG) and rs710218 (AA) when compared to those with a recessive allele (GA/AA and AT/TT respectively) (P < 0.04). The heterozygous genotype associated with AKT SNP 1130214 (GT) had a higher CD4+Glut1+ T cell percentage when compared to the dominant homozygous genotype (GG) (P = 0.0068). The frequency of circulating CD4+Glut1+ T cells and the rs1385129 SLC2A1 SNP may predict the rate of HIV disease progression and CD4+ T cell recovery in untreated and treated infection, respectively.

Dendritic cells from HIV-1 infected individuals are less responsive to toll-like receptor (TLR) ligands.

We compared TLR responsiveness in PBMC from HIV-1-infected and uninfected individuals using the TLR agonists: TLR7 (3M-001), TLR8 (3M-002), and TLR7/8 (3M-011). Activation and maturation of plasmacytoid dendritic cells (pDC) were measured by evaluating CD86, CD40, and CD83 expression and myeloid dendritic cell (mDC) activation was measured by evaluating CD40 expression. All agonists tested induced activation and maturation of pDC in PBMC cultures of cells from HIV+ and HIV- individuals. The TLR7 agonist induced significantly less pDC maturation in cells from HIV+ individuals. Quantitative assessment of secreted IFN-alpha and pro-inflammatory cytokines at the single cell level showed that pDC from HIV+ individuals stimulated with TLR7 and TLR7/8 induced IFN-alpha. TLR8 and TLR7/8 agonists induced IL-12 and COX-2 expression in mDC from HIV+ and HIV- individuals. Understanding pDC and mDC activation and maturation in HIV-1 infection could lead to more rational development of immunotherapeutic strategies to stimulate the adaptive immune response to HIV-1.

Identification of CD19 and CD20 peptides for induction of antigen-specific CTLs against B-cell malignancies.

The purpose of these studies was to develop immunogenic peptides derived from the CD19 and CD20 self-antigens for the induction of antigen-specific CTLs against B-cell malignancies. A total of seven peptides were designed and examined for their HLA-A2.1 affinity and immunogenicity. Of these peptides, we identified two highly immunogenic HLA-A2.1-specific peptides, CD19(150-158) (KLMSPKLYV) and CD20(188-196) (SLFLGILSV), which were capable of inducing peptide-specific CTLs. The CTLs displayed HLA-A2.1-restricted and antigen-specific cytotoxicity against Burkitt's lymphoma, chronic B cell leukemia, and multiple myeloma cell lines. The CD19 or CD20 peptide-specific CTL cytotoxicity was confirmed using HLA-A2.1(+) T2 cells presenting the appropriate peptide. No cytotoxic activity was observed against T2 cells presenting the irrelevant MAGE-3 peptide or T2 cells alone. In addition, the CTLs displayed a significant (P < 0.05) increase in cell proliferation and IFN-gamma secretion (>830 ng/mL) following restimulation with HLA-A2.1(+)/CD19(+)/CD20(+) tumor cells. The CTLs also displayed a distinct phenotype consisting of a high percentage of CD69(+)/CD45RO(+) and a low percentage of CD45RA(+)/CCR7(+) CD4(+) or CD8(+) T cells characteristic of effector memory cell population. Cyclic guanosine 3',5'-monophosphate culture conditions using serum-free AIM-V medium containing human AB serum, recombinant human interleukin 2 (Proleukin) and CD3/CD28 Dynabeads were developed resulting in a 35-fold expansion of CD20 peptide-specific CTLs. The expanded CD20-CTLs retained their cytotoxic activity (28-49%) against the Burkitt's lymphoma cell line. In conclusion, we report here on the identification of novel immunogenic CD19(150-158) (KLMSPKLYV) and CD20(188-196) (SLFLGILSV) peptides that have immunotherapeutic potentials as peptide vaccines or targeted T-cell therapies for treating B-cell malignancies.

Differential CD4+ cell count increase and CD4+ :  CD8+ ratio normalization with maraviroc compared with tenofovir.

OBJECTIVE: Studies exploring the immunologic effects of maraviroc (MVC) have produced mixed results; hence, it remains unclear whether MVC has unique immunologic effects in comparison with other antiretroviral drugs. We sought to determine whether MVC has differential effects compared with tenofovir disoproxil fumarate (TDF) during initial antiretroviral therapy. DESIGN: Prospective study in AIDS Clinical Trials Group A5303, a double-blind, placebo-controlled trial (N = 262) of MVC vs. TDF, each combined with boosted darunavir and emtricitabine. METHODS: A total of 31 cellular and soluble biomarkers were assayed at weeks 0 and 48. Polychromatic flow cytometry was performed on cryopreserved peripheral blood mononuclear cells. Soluble markers were assayed in plasma using ELISA kits. Analyses were as treated. RESULTS: Analyses included 230 participants (119 in MVC arm and 111 in TDF arm). Over 48 weeks of treatment, no significant differences were detected in declines in markers of inflammation and activation with MVC vs. TDF. A greater CD4 T-cell count increase (median +234 vs. +188 cells/µl, P = 0.036), a smaller CD8 T-cell count decrease (-6 vs. -109 cells/µl, P = 0.008), and a smaller CD4 : CD8 ratio increase (0.26 vs. 0.39, P = 0.003) occurred with MVC. Among participants with a baseline CD4 : CD8 ratio less than 1, a smaller proportion of MVC group normalized to a ratio greater than 1 at week 48 (15 and 36%, P < 0.001). CONCLUSION: MVC resulted in less improvement in the CD4 : CD8 ratio driven by greater increase in CD4 cell count but smaller decline in CD8 cell count. Changes in soluble or cellular biomarkers of inflammation and immune activation were not different between MVC and TDF.

Heteroclitic CD33 peptide with enhanced anti-acute myeloid leukemic immunogenicity.

The goal of these studies was to engineer a synthetic CD33 peptide with enhanced immunogenicity for the induction of acute myeloid leukemia (AML)-specific CTLs. Eight modified CD33 peptides YLISGDSPV, YIGSGDSPV, YIIIGDSPV, YIILGDSPV, YIISGISPV, YIISGDLPV, YIISGDSWV and YIISGDSPL were designed for increased HLA-A2.1 or T cell receptor affinity and compared with the native CD33(65-73) peptide, AIISGDSPV, for enhanced immunogenicity. The YLISGDSPV peptide was found to be the most immunogenic epitope producing highly cytolytic CTLs against AML target cells. The CTLs generated withYLISGDSPV peptide showed CD33 peptide-specificity through targeting of both native (AIISGDSPV) and modified (YLISGDSPV) peptide presenting EBV-BLCL. The CTL cultures displayed a distinct phenotype consisting of a high percentage of activated memory (CD69(+)/CD45RO(+))-CD8(+)and a low percentage of naive (CD45RA(+)/CCR7(+))-CD8(+)cells. In addition, T-cell clones specific to the YLISGDSPV peptide were isolated and characterized to target AML cells. The clones exhibited both HLA-A2.1-restricted and AML cell-specific cytotoxicity that was mediated through a granule-dependent pathway. More importantly, the CTL clones did not lyse or inhibit the proliferation of normal CD34(+) progenitor cells. In conclusion, we report on the identification of a highly immunogenic heteroclitic YLISGDSPV CD33 epitope that is a promising candidate for immunotherapy targeting AML.

Short communication: Apoptosis pathways in HIV-1-infected patients before and after highly active antiretroviral therapy: relevance to immune recovery.

Investigations into apoptotic pathways, intrinsic and extrinsic, and the effects of highly active antiretroviral therapy (HAART) on T cell death via those pathways may provide insight into the mechanisms of and barriers to immune recovery. HIV-1-infected patients were enrolled into a randomized, controlled study of the immune effects of a lopinavir/ritonavir (LPV/r)-based versus an efavirenz (EFV)-based HAART regimen in antiretroviral-naive subjects with CD4(+) counts <350 cells/mm(3). Patients were randomized to receive TDF/FTC/EFZ or TDF/FTC plus LPV/r. Fourteen patients were enrolled and 10 patients completed 6 months of therapy as per the protocol. CD4(+) counts were measured before and during HAART therapy. We isolated T cell subsets to measure ex vivo apoptosis by propidium iodide staining. We also assessed caspase activation for the intrinsic and extrinsic pathways of apoptosis, as well as effector caspase activation. We also measured mitochondrial membrane potential. Cells were analyzed by flow cytometry. All patients had increased activation of caspase 8 (extrinsic pathway), caspase 9 (intrinsic pathway), effector caspases 3/7, and low mitochondrial membrane potential at baseline compared to controls. By 4 weeks, there was a decrease in activation of all caspases, but little further decrease by week 24. T cell mitochondrial membrane potential did not increase until week 12, but continued to increase until week 24. The only predictor of CD4(+) count increase was the increase in mitochondrial membrane potential of naive cells at 6 months (r=0.66, p=0.038). This suggests that positive selection of naive CD4(+) T cells in the thymus is the major determinant of CD4(+) recovery.

Association of chronic hepatitis C infection with T-cell phenotypes in HIV-negative and HIV-positive women.

BACKGROUND: Hepatitis C virus (HCV) viremia is thought to have broad systemic effects on the cellular immune system that go beyond its impact on just those T cells that are HCV specific. However, previous studies of chronic HCV and circulating T-cell subsets (activation and differentiation phenotypes) in HIV negatives used general population controls, rather than a risk-appropriate comparison group. Studies in HIV positives did not address overall immune status (total CD4⁺ count). METHODS: We used fresh blood from HIV-positive and at-risk HIV-negative women, with and without chronic HCV, to measure percentages of activated CD4⁺ and CD8⁺ T cells, Tregs, and T-cell differentiation phenotypes (naive, central memory, effector memory (EM), and terminally differentiated effector). This included 158 HIV negatives and 464 HIV positives, of whom 18 and 63, respectively, were HCV viremic. RESULTS: In multivariate models of HIV negatives, HCV viremia was associated with 25% fewer naive CD4⁺ (P = 0.03), 33% more EM CD4⁺ (P = 0.0002), and 37% fewer central memory CD8⁺ (P = 0.02) T cells. Among HIV positives, we observed only 1 of these 3 relationships: higher percentage of EM CD4⁺ among HCV viremic women. Furthermore, the association with EM CD4⁺ among HIV positives was limited to individuals with diminished immune status (total CD4⁺ count ≤500 cells/µL), as were associations of HCV viremia with higher percentages of activated CD4⁺ and Tregs. Among HIV positives with high CD4⁺ count, no significant associations were observed. CONCLUSIONS: These data suggest that HCV viremia in HIV negatives is associated with accelerated T-cell differentiation, but among HIV positives, the impact of HCV viremia is less straightforward and varies by total CD4v count.

The relation of plasmacytoid dendritic cells (pDCs) and regulatory T-cells (Tregs) with HPV persistence in HIV-infected and HIV-uninfected women.

Other than CD4+ count, the immunologic factors that underlie the relationship of HIV/AIDS with persistent oncogenic HPV (oncHPV) and cervical cancer are not well understood. Plasmacytoid dendritic cells (pDCs) and regulatory T-cells (Tregs) are of particular interest. pDCs have both effector and antigen presenting activity and, in HIV-positive patients, low pDC levels are associated with opportunistic infections. Tregs downregulate immune responses, and are present at high levels in HIV-positives. The current pilot study shows for the first time that low pDC and high Treg levels may be significantly associated with oncHPV persistence in both HIV-positive and HIV-negative women. Larger studies are now warranted.