Contrasting Roles for TLR Ligands in HIV-1 Pathogenesis

The first line of a host's response to various pathogens is triggered by their engagement of cellular pattern recognition receptors (PRRs). Binding of microbial ligands to these receptors leads to the induction of a variety of cellular factors that alter intracellular and extracellular environment and interfere directly or indirectly with the life cycle of the triggering pathogen. Such changes may also affect any coinfecting microbe. Using ligands to Toll-like receptors (TLRs) 5 and 9, we examined their effect on human immunodeficiency virus (HIV)-1 replication in lymphoid tissue ex vivo. We found marked differences in the outcomes of such treatment. While flagellin (TLR5 agonist) treatment enhanced replication of CC chemokine receptor 5 (CCR 5)-tropic and CXC chemokine receptor 4 (CXCR4)-tropic HIV-1, treatment with oligodeoxynucleotide (ODN) M362 (TLR9 agonist) suppressed both viral variants. The differential effects of these TLR ligands on HIV-1 replication correlated with changes in production of CC chemokines CCL3, CCL4, CCL5, and of CXC chemokines CXCL10, and CXCL12 in the ligand-treated HIV-1-infected tissues. The nature and/or magnitude of these changes were dependent on the ligand as well as on the HIV-1 viral strain. Moreover, the tested ligands differed in their ability to induce cellular activation as evaluated by the expression of the cluster of differentiation markers (CD) 25, CD38, CD39, CD69, CD154, and human leukocyte antigen D related (HLA)-DR as well as of a cell proliferation marker, Ki67, and of CCR5. No significant effect of the ligand treatment was observed on apoptosis and cell death/loss in the treated lymphoid tissue ex vivo. Our results suggest that binding of microbial ligands to TLRs is one of the mechanisms that mediate interactions between coinfected microbes and HIV-1 in human tissues. Thus, the engagement of appropriate TLRs by microbial molecules or their mimetic might become a new strategy for HIV therapy or prevention

Caractérisations physicochimiques de biofilms synthétisés à partir de la pectine et de la gélatine

Trois types de biofilms à base de polymères naturels ont été préparés à partir de la pectine, un polyélectrolyte anionique, et de la gélatine, une espèce cationique. Les propriétés physicochimiques (épaisseur,perméabilité à la vapeur d’eau et pouvoir gonflant) des biofilms ont été déterminées; de même, leur morphologie a été évaluée. Au niveau micrométrique, les épaisseurs des biofilms étaient respectivement de101,2±0,2 μm; 64,6±0,1 μm et 39,0±0,1 μm pour la gélatine, le mélange gélatine/pectine et la pectine. Le pouvoir gonflant était de 300% pour la gélatine, 215% pour le mélange gélatine/pectine et 90% pour la pectine.La perméabilité à la vapeur d’eau était de 9,20 g mm/m2 h KPa pour la gélatine; 6,59 g mm/m2 h KPa pour le mélange gélatine/pectine et 3,98 g mm/m2 h KPa pour la pectine. Au niveau morphologique, des différencessignificatives ont été observées. Toutefois, les différents films formulés ont mis en évidence des potentialités physicochimiques intéressantes.Mots clés : Biofilms, polymères naturels, analyse physicochimiqu

The role of crosslinking on the physical properties of gelatin based films

12 págs.; 7 figs.; 4 tabs.© 2015, Springer-Verlag Berlin Heidelberg. The crosslinking of gelatin using crosslinking agents based on condensation of the aldehyde groups and ε-amine groups present in lysine and hydroxylysine rests is a very attractive method reported recently. The present work deals with different films prepared from commercial gelatin of type B and animal origin, aiming at an improvement of physical properties. These films were modified by two plasticizing agents (glycerol, GLY, and poly (vinyl alcohol), PVA) and/or crosslinked by glutaraldehyde (GTA). The number of ε-amino groups present in the gelatin chains, before and after modification, was determined by the method of protein dosage using 2,4,6-trinitro benzene sulfonic acid (TNBS). The addition of the plasticizing and/or crosslinking agents induced a decrease in the number of ε-amino-groups due to the fact that these groups are involved in the physical and/or chemical crosslinking reactions occurring among the different components. The variation of the crosslinking ratio was studied as a function of formulation type, crosslinking nature and GTA concentration. The use of microhardness (H) in this study emphasizes the effect of the crosslinking on the improvement of the micromechanical properties. The study of differential scanning calorimetry reveals that crosslinking induces a drastic decrease of crystallinity in the samples.FJBC gratefully acknowledges the MINECO, Spain (grant MAT 2013–47898-C2-1-R) for the generous support of this work.Peer Reviewe

Neutralization sensitivity of a novel HIV-1 CRF01_AE panel of infectious molecular clones

BACKGROUND: HIV-1 CRF01_AE is dominant in Thailand where RV144 vaccine trial was conducted. To study immune correlates of protection in ongoing trials, CRF01_AE derived reagents are essential. Here we present a panel of 14 HIV-1 infectious molecular clones (IMC) identified from different stages of infection, and characterization of their neutralization sensitivity using two standard assays. METHODS: One full-length IMC was constructed using a transmitted-founder virus to express Renilla luciferase (LucR) reporter gene and full-length envelopes (envs) of exogenous HIV-1. A panel of IMCs was generated, expressing envs of viruses from acute (Fiebig stages I/II and I-IV) and chronic (>Febig VI) infection. Neutralization assays were performed using TZM-bl or A3R5 cell lines, and sera or monoclonal antibodies (mAbs). Wilcoxon matched-paired test was used to assess neutralization differences between assays and reagents; correlation coefficients were evaluated by linear regression. RESULTS: Neutralization potency observed was significantly higher in the A3R5 assay when testing mAbs and serum pools (p<0.0001); the stage of infection from which env was derived did not associate with IMC neutralization sensitivity. Neutralization values from A3R5 and TZM-bl assays were strongly correlated when mAbs were tested (R=0.7, p<0.0001), but a weaker association was seen with serum pools (R=0.17, p=0.03). CONCLUSIONS: This novel panel of CRF01_AE reporter-IMC is useful for assessing vaccine-induced neutralizing antibodies in multiple assays, including those utilizing primary cell targets. The significant differences in TZM-bl and A3R5 neutralization sensitivity, as well as the poor association when using polyclonal sera indicates the need for caution in choosing one specific platform