Huang J.,National Institute of Allergy and Infectious Diseases |
Kang B.H.,National Institute of Allergy and Infectious Diseases |
Pancera M.,National Institute of Allergy and Infectious Diseases |
Lee J.H.,Scripps Research Institute |
And 26 more authors.
Nature | Year: 2014
The isolation of human monoclonal antibodies is providing important insights into the specificities that underlie broad neutralization of HIV-1 (reviewed in ref. 1). Here we report a broad and extremely potent HIV-specific monoclonal antibody, termed 35O22, which binds a novel HIV-1 envelope glycoprotein (Env) epitope. 35O22 neutralized 62% of 181 pseudoviruses with a half-maximum inhibitory concentration (IC50) <50 μg ml-1. The median IC50 of neutralized viruses was 0.033 μg ml-1, among the most potent thus far described. 35O22 did not bind monomeric forms of Env tested, but did bind the trimeric BG505 SOSIP.664. Mutagenesis and a reconstruction by negative-stain electron microscopy of the Fab in complex with trimer revealed that it bound to a conserved epitope, which stretched across gp120 and gp41. The specificity of 35O22 represents a novel site of vulnerability on HIV Env, which serum analysis indicates to be commonly elicited by natural infection. Binding to this new site of vulnerability may thus be an important complement to current monoclonal-antibody-based approaches to immunotherapies, prophylaxis and vaccine design. ©2014 Macmillan Publishers Limited. All rights reserved.
PubMed | Fred Hutchinson Cancer Research Center, University of KwaZulu - Natal, Vanderbilt University, National Institute of Allergy and Infectious Diseases and 3 more.
Type: Journal Article | Journal: PLoS pathogens | Year: 2017
Computational neutralization fingerprinting, NFP, is an efficient and accurate method for predicting the epitope specificities of polyclonal antibody responses to HIV-1 infection. Here, we present next-generation NFP algorithms that substantially improve prediction accuracy for individual donors and enable serologic analysis for entire cohorts. Specifically, we developed algorithms for: (a) selection of optimized virus neutralization panels for NFP analysis, (b) estimation of NFP prediction confidence for each serum sample, and (c) identification of sera with potentially novel epitope specificities. At the individual donor level, the next-generation NFP algorithms particularly improved the ability to detect multiple epitope specificities in a sample, as confirmed both for computationally simulated polyclonal sera and for samples from HIV-infected donors. Specifically, the next-generation NFP algorithms detected multiple specificities in twice as many samples of simulated sera. Further, unlike the first-generation NFP, the new algorithms were able to detect both of the previously confirmed antibody specificities, VRC01-like and PG9-like, in donor CHAVI 0219. At the cohort level, analysis of ~150 broadly neutralizing HIV-infected donor samples suggested a potential connection between clade of infection and types of elicited epitope specificities. Most notably, while 10E8-like antibodies were observed in infections from different clades, an enrichment of such antibodies was predicted for clade B samples. Ultimately, such large-scale analyses of antibody responses to HIV-1 infection can help guide the design of epitope-specific vaccines that are tailored to take into account the prevalence of infecting clades within a specific geographic region. Overall, the next-generation NFP technology will be an important tool for the analysis of broadly neutralizing polyclonal antibody responses against HIV-1.
Wang J.,Torrey Pines Institute for Molecular Studies |
Wang J.,San Diego Biomedical Research Institute |
Ciaraldi T.P.,VA San Diego Healthcare System |
Ciaraldi T.P.,University of California at San Diego |
And 2 more authors.
Journal of Obesity | Year: 2015
Objective. Increased coagulation activation may contribute to the high incidence of cardiovascular complications observed in obese and type 2 diabetes (T2D) subjects. Although tissue factor (TF), the primary initiator of coagulation is increased in obesity, its expression in adipose tissues and its association with metabolic parameters are unclear. We sought to compare TF expression in plasma and adipose tissues of obese subjects with and without T2D, its correlation with metabolic parameters, and regulation in response to antidiabetic drugs. Methods Subjects were recruited from diabetes clinics and adipose tissue was obtained by needle biopsy of lower subcutaneous abdominal depot. For the intervention study, subjects were randomized into treatment groups with rosiglitazone or metformin for 4 months. Results. Plasma TF antigen, activity, and adipose TF mRNA were greater in obese T2D subjects compared with obese nondiabetics. Plasma TF activity correlated with fasting insulin, glucose, and free fatty acids, (FFAs), and adipose TF mRNA correlated with plasma FFA. Plasma TF activity was reduced by metformin and increased with rosiglitazone treatment. Conclusions. Specific diabetes-related metabolic parameters, but not obesity per se, are correlated with TF expression. Regulation of TF activity by different classes of antidiabetic drugs may relate to protective or adverse cardiovascular outcomes. © 2015 Jing Wang et al.
PubMed | CAS Institute of Biophysics, Tulane National Primate Research Center, Weatherall Institute of Molecular Medicine, Scripps Research Institute and 5 more.
Type: Journal Article | Journal: PLoS pathogens | Year: 2015
Eliciting broad tier 2 neutralizing antibodies (nAbs) is a major goal of HIV-1 vaccine research. Here we investigated the ability of native, membrane-expressed JR-FL Env trimers to elicit nAbs. Unusually potent nAb titers developed in 2 of 8 rabbits immunized with virus-like particles (VLPs) expressing trimers (trimer VLP sera) and in 1 of 20 rabbits immunized with DNA expressing native Env trimer, followed by a protein boost (DNA trimer sera). All 3 sera neutralized via quaternary epitopes and exploited natural gaps in the glycan defenses of the second conserved region of JR-FL gp120. Specifically, trimer VLP sera took advantage of the unusual absence of a glycan at residue 197 (present in 98.7% of Envs). Intriguingly, removing the N197 glycan (with no loss of tier 2 phenotype) rendered 50% or 16.7% (n = 18) of clade B tier 2 isolates sensitive to the two trimer VLP sera, showing broad neutralization via the surface masked by the N197 glycan. Neutralizing sera targeted epitopes that overlap with the CD4 binding site, consistent with the role of the N197 glycan in a putative glycan fence that limits access to this region. A bioinformatics analysis suggested shared features of one of the trimer VLP sera and monoclonal antibody PG9, consistent with its trimer-dependency. The neutralizing DNA trimer serum took advantage of the absence of a glycan at residue 230, also proximal to the CD4 binding site and suggesting an epitope similar to that of monoclonal antibody 8ANC195, albeit lacking tier 2 breadth. Taken together, our data show for the first time that strain-specific holes in the glycan fence can allow the development of tier 2 neutralizing antibodies to native spikes. Moreover, cross-neutralization can occur in the absence of protecting glycan. Overall, our observations provide new insights that may inform the future development of a neutralizing antibody vaccine.
PubMed | University of California at San Diego, Scripps Research Institute, Torrey Pines Institute for Molecular Studies, San Diego Biomedical Research Institute and Veterans Administration San Diego Healthcare System
Type: Journal Article | Journal: Journal of thrombosis and haemostasis : JTH | Year: 2016
Wang J.,Torrey Pines Institute for Molecular Studies |
Wang J.,San Diego Biomedical Research Institute |
Chakrabarty S.,Scripps Research Institute |
Bui Q.,Torrey Pines Institute for Molecular Studies |
And 4 more authors.
American Journal of Pathology | Year: 2014
Failure to inhibit hepatic gluconeogenesis is a major mechanism contributing to fasting hyperglycemia in type 2 diabetes and, along with steatosis, is the hallmark of hepatic insulin resistance. Obesity is associated with chronic inflammation in multiple tissues, and hepatic inflammation is mechanistically linked to both steatosis and hepatic insulin resistance. Here, we delineate a role for coagulation signaling via tissue factor (TF) and proteinase-activated receptor 2 (PAR2) in obesity-mediated hepatic inflammation, steatosis, and gluconeogenesis. In diet-induced obese mice, TF tail signaling independent of PAR2 drives CD11b+CD11c+hepaticmacrophage recruitment, and TF-PAR2 signaling contributes to the accumulation of hepatic CD8+T cells. Transcripts of key pathways of gluconeogenesis, lipogenesis, and inflammatory cytokines were reduced in high-fat dietefedmice that lack the cytoplasmic domain of TF (F3) (TFδCT) or that are deficient in PAR2 (F2rl1), as well as by pharmacological inhibition of TF-PAR2 signaling in diet-induced obese mice. These gluconeogenic, lipogenic, and inflammatory pathway transcripts were similarly reduced in response to genetic ablation or pharmacological inhibition of TF-PAR2 signaling in hematopoietic cells and were mechanistically associated with activation of AMP-activated protein kinase (AMPK). These findings indicate that hematopoietic TF-PAR2 signaling plays a pivotal role in the hepatic inflammatory responses, steatosis, and hepatic insulin resistance that lead to systemic insulin resistance and type 2 diabetes in obesity. Copyright © 2015 American Society for Investigative Pathology.
PubMed | Scripps Research Institute, Torrey Pines Institute for Molecular Studies, San Diego Biomedical Research Institute and Biosettia, Inc.
Type: | Journal: European journal of immunology | Year: 2017
Secreted microvesicles (MVs) are potent inflammatory triggers that stimulate autoreactive B and T cells, causing Type 1 Diabetes in non-obese diabetic (NOD) mice. Proteomic analysis of purified MVs released from islet cells detected the presence of endogenous retrovirus (ERV) antigens, including Env and Gag sequences similar to the well-characterized murine leukemia retroviruses. This raises the possibility that ERV antigens may be expressed in the pancreatic islets via MV secretion. Using virus-like particles produced by co-expressing ERV Env and Gag antigens, and a recombinant gp70 Env protein, we demonstrated that NOD but not diabetes-resistant mice developed anti-Env autoantibodies that increase in titer as disease progresses. A lentiviral-based RNA interference knockdown of Gag revealed that Gag contributes to the MV-induced T-cell response, whose diabetogenic function can be demonstrated via cell-transfer into immune-deficient mice. Finally, we observed that Gag and Env are expressed in NOD islet-derived primary mesenchymal stem cells (MSCs). However, MSCs derived from the islets of diabetes-resistant mice do not express the antigens. Taken together, abnormal ERV activation and secretion of MVs may induce anti-retroviral responses to trigger autoimmunity. This article is protected by copyright. All rights reserved.
Ruf W.,University Hospital Freiburg |
Samad F.,San Diego Biomedical Research Institute
Hamostaseologie | Year: 2015
Obesity is a major cause for a spectrum of metabolic syndrome-related diseases that include insulin resistance, type 2 diabetes, and steatosis of the liver. Inflammation elicited by macrophages and other immune cells contributes to the metabolic abnormalities in obesity. In addition, coagulation activation following tissue factor (TF) upregulation in adipose tissue is frequently found in obese patients and particularly associated with diabetic complications. Genetic and pharmacological evidence indicates that TF makes significant contributions to the development of the metabolic syndrome by signaling through G protein-coupled protease activated receptors (PARs). Adipocyte TF-PAR2 signaling contributes to diet-induced obesity by decreasing metabolism and energy expenditure, whereas hematopoietic TF-PAR2 signaling is a major cause for adipose tissue inflammation, hepatic steatosis and inflammation, as well as insulin resistance. In the liver of mice on a high fat diet, PAR2 signaling increases transcripts of key regulators of gluconeogenesis, lipogenesis and inflammatory cytokines. Increased markers of hepatic gluconeogenesis correlate with decreased activation of AMP-activated protein kinase (AMPK), a known regulator of these pathways and a target for PAR2 signaling. Clinical markers of a TF-induced prothrombotic state may thus indicate a risk in obese patient for developing complications of the metabolic syndrome. © Schattauer 2015.