Species Tropism of Chimeric SHIV Clones Containing HIV-1 Subtype-A and Subtype-E Envelope Genes

AbstractTo analyze HIV-1 genes in a nonhuman primate model for lentivirus infection and AIDS, recombinant SIV/HIV-1 (SHIV) clones were constructed from two HIV-1 subtype-A isolates (HIV-1SF170 and HIV-1Q23–17 from individuals in Africa) and two HIV-1 subtype-E isolates (HIV-19466 and HIV-1CAR402 from AIDS patients in Thailand and Africa), respectively. These four SHIV clones, designated SHIV-A-170, SHIV-A-Q23, SHIV-9466.33, and SHIV-E-CAR, contain envelope (env) genes from the subtype-A or -E viruses. Interestingly, SHIV-A-170, SHIV-A-Q23, and SHIV-9466.33 were restricted for replication in cultures of macaque lymphoid cells, whereas SHIV-E-CAR replicated efficiently in these cells. Additional studies to define the block to replication in macaque cells were focused on the subtype-E clone SHIV-9466.33. A SHIV intragenic env clone, containing sequence-encompassing V1/V2 regions of HIV-1CAR402 and V3/V4/V5 regions of SHIV-9466.33, infected and replicated in macaque lymphoid cells. These results indicated that the sequence-encompassing V1/V2 region of HIV-19466 was responsible for the block of the SHIV-9466.33 replication in macaque cells. Analysis of viral DNA in acutely infected macaque cells revealed that SHIV-9466.33 was blocked at a step at/or before viral DNA synthesis, presumably during the process of virion entry into cells. In a fluorescence-based cell–cell fusion assay, fusion pore formation readily took place in cocultures of cells expressing the SHIV-9466.33 env glycoprotein with macaque T-lymphoid cells. Taken together, these results demonstrated that the block of SHIV-9466.33 replication in macaque cells is at an early step after fusion pore formation but before reverse transcription

Superior efficacy of a human immunodeficiency virus vaccine combined with antiretroviral prevention in simian-human immunodeficiency virus-challenged nonhuman primates

International audienc

Structural characteristics correlate with immune responses induced by HIV envelope glycoprotein vaccines

AbstractHIV envelope glycoprotein (Env) is the target for inducing neutralizing antibodies. Env is present on the virus surface as a trimer, and, upon binding to CD4, a cascade of events leads to structural rearrangement exposing the co-receptor binding site and entry into the CD4+ host target cells. We have designed monomeric and trimeric Env constructs with and without deletion of the variable loop 2 (ΔV2) from SF162, a subtype B primary isolate, and performed biophysical, biochemical and immunological studies to establish a potential structure–functional relationship. We expressed these Envs in CHO cells, purified the proteins to homogeneity and performed biophysical studies to define the binding properties to CD4, structural characteristics and exposure of epitopes recognized by b12 and CD4i mAb (17B) on both full-length and mutant HIV Env proteins. Parameters evaluated include oligomerization state, number and affinity of CD4 binding sites, enthalpy and entropy of the Env–CD4 interaction and affinity for b12 and 17b mAbs. We observed one CD4 binding site per monomer and three active CD4 binding sites per trimer. A 40-fold difference in affinity of the gp120 monomer vs. the o-gp140 trimer towards CD4 was observed (Kd = 58 nM and 1.5 nM, respectively), whereas only a 2-fold difference was observed for the V2 deleted Envs (Kd of gp120ΔV2 = 19 nM, Kd of o-gp140DV2 = 9.3 nM). Monomers had 3-fold higher affinity to the mAb 17b and at least 3-fold weaker affinity to b12 compared to trimers, with gp120DV2 having the weakest affinity for b12 (Kd = 446 nM). Affinity of CD4 binding correlated with proportion of the antibodies induced against the conformational epitopes by the corresponding Envs, and changes in mAb binding correlated with the induction of antibodies directed against linear epitopes. Furthermore, biophysical analysis reveals that the V2 deletion has broad structural implications in the monomer not shared by the trimer, and these changes are reflected in the quality of the immune responses induced in rabbits. These data suggest that biophysical characteristics of HIV Env, such as affinity for CD4, and exposure of important neutralizing epitopes, such as those recognized by b12 mAb, may be important predictors of its in vivo efficacy and may serve as important surrogate markers for screening Env structures as potential vaccine candidates

Systematic review of the performance of HIV viral load technologies on plasma samples.

BACKGROUND: Viral load (VL) monitoring is the standard of care in developing country settings for detecting HIV treatment failure. Since 2010 the World Health Organization has recommended a phase-in approach to VL monitoring in resource-limited settings. We conducted a systematic review of the accuracy and precision of HIV VL technologies for treatment monitoring. METHODS AND FINDINGS: A search of Medline and Embase was conducted for studies evaluating the accuracy or reproducibility of commercially available HIV VL assays. 37 studies were included for review including evaluations of the Amplicor Monitor HIV-1 v1.5 (n = 25), Cobas TaqMan v2.0 (n = 11), Abbott RealTime HIV-1 (n = 23), Versant HIV-1 RNA bDNA 3.0 (n = 15), Versant HIV-1 RNA kPCR 1.0 (n = 2), ExaVir Load v3 (n = 2), and NucliSens EasyQ v2.0 (n = 1). All currently available HIV VL assays are of sufficient sensitivity to detect plasma virus levels at a lower detection limit of 1,000 copies/mL. Bias data comparing the Abbott RealTime HIV-1, TaqMan v2.0 to the Amplicor Monitor v1.5 showed a tendency of the Abbott RealTime HIV-1 to under-estimate results while the TaqMan v2.0 overestimated VL counts. Compared to the Amplicor Monitor v1.5, 2-26% and 9-70% of results from the Versant bDNA 3.0 and Abbott RealTime HIV-1 differed by greater than 0.5log10. The average intra and inter-assay variation of the Abbott RealTime HIV-1 were 2.95% (range 2.0-5.1%) and 5.44% (range 1.17-30.00%) across the range of VL counts (2log10-7log10). CONCLUSIONS: This review found that all currently available HIV VL assays are of sufficient sensitivity to detect plasma VL of 1,000 copies/mL as a threshold to initiate investigations of treatment adherence or possible treatment failure. Sources of variability between VL assays include differences in technology platform, plasma input volume, and ability to detect HIV-1 subtypes. Monitoring of individual patients should be performed on the same technology platform to ensure appropriate interpretation of changes in VL. Prospero registration # CD42013003603

Systematic review of the use of dried blood spots for monitoring HIV viral load and for early infant diagnosis.

BACKGROUND: Dried blood spots (DBS) have been used as alternative specimens to plasma to increase access to HIV viral load (VL) monitoring and early infant diagnosis (EID) in remote settings. We systematically reviewed evidence on the performance of DBS compared to plasma for VL monitoring and EID. METHODS AND FINDINGS: Thirteen peer reviewed HIV VL publications and five HIV EID papers were included. Depending on the technology and the viral load distribution in the study population, the percentage of DBS samples that are within 0.5 log of VL in plasma ranged from 52-100%. Because the input sample volume is much smaller in a blood spot, there is a risk of false negatives with DBS. Sensitivity of DBS VL was found to be 78-100% compared to plasma at VL below 1000 copies/ml, but this increased to 100% at a threshold of 5000 copies/ml. Unlike a plasma VL test which measures only cell free HIV RNA, a DBS VL also measures proviral DNA as well as cell-associated RNA, potentially leading to false positive results when using DBS. The systematic review showed that specificity was close to 100% at DBS VL above 5000 copies/ml, and this threshold would be the most reliable for predicting true virologic failure using DBS. For early infant diagnosis, DBS has a sensitivity of 100% compared to fresh whole blood or plasma in all studies. CONCLUSIONS: Although limited data are available for EID, DBS offer a highly sensitive and specific sampling strategy to make viral load monitoring and early infant diagnosis more accessible in remote settings. A standardized approach for sampling, storing, and processing DBS samples would be essential to allow successful implementation. TRIAL REGISTRATION: PROSPERO Registration #: CRD42013003621

Impact of antibody quality and anamnestic response on viremia control post-challenge in a combined Tat/Env vaccine regimen in rhesus macaques

AbstractPreviously, priming rhesus macaques with Adenovirus type 5 host range mutant-recombinants encoding Tat and Env and boosting with Tat and Env protein in MPL-SE controlled chronic viremia by 4 logs following homologous intravenous SHIV89.6P challenge. Here we evaluated Tat, Env, and Tat/Env regimens for immunogenicity and protective efficacy using clade C Env, alum adjuvant, and a heterologous intrarectal SHIV1157ipd3N4 challenge. Despite induction of strong cellular and humoral immunity, Tat/Env group T and B-cell memory responses were not significantly enhanced over Tat- or Env-only groups. Lack of viremia control post-challenge was attributed to lower avidity Env antibodies and no anamnestic ADCC response or SHIV1157ipd3N4 neutralizing antibody development post-challenge. Poor biologic activity of the Tat immunogen may have impaired Tat immunity. In the absence of sterilizing immunity, strong anamnestic responses to heterologous virus can help control viremia. Both antibody breadth and optimal adjuvanticity are needed to elicit high-quality antibody for protective efficacy

Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.

BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24 months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500 steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30 minutes spent performing activities ≥500 counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24 months), both the number of steps per day (per 500 steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity ≥500 counts per minute (per 30 minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score >10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500

Hookah smoking is strongly associated with diabetes mellitus, metabolic syndrome and obesity: a population-based study

Objectives The adverse effects of cigarette smoking have been widely studied before, whilst the effects of hookah smoking has received less attention, although it is a common habit in the Middle East. Here we have investigated the effects of cigarette and hookah smoking on biochemical characteristics in a representative population sample derived from the Mashhad stroke and heart atherosclerotic disorder (MASHAD) cohort study, from Northeastern Iran. Study design A total of 9840 subjects from the MASHAD population study were allocated to five groups; non-smokers (6742), ex-smokers (976), cigarette smokers (864), hookah smokers (1067), concomitant cigarette and hookah smokers (41). Methods Baseline characteristics were recorded in a questionnaire. Biochemical characteristics were measured by routine methods. Data were analyzed using SPSS software and p < 0.05 was considered significant. Results After adjustment for age and sex; the presence of CVD, obesity, metabolic syndrome, DM and dyslipidemia were significantly (p < 0.001) related to smoking status. After multivariate analysis, HDL (p < 0.001), WBC (p < 0.001), MCV (p < 0.05), PLT (p < 0.01) and RDW (p < 0.001), and the presence of CVD (p < 0.01), obesity (p < 0.001), metabolic syndrome (p < 0.05) and DM (p < 0.01) remained significant between cigarette smokers and non-smokers. Between hookah smokers and non-smokers; uric acid (p < 0.001), PLT (p < 0.05) and RDW (p < 0.05), and the presence of obesity (p < 0.01), metabolic syndrome (p < 0.001), diabetes (p < 0.01) and dyslipidemia (p < 0.01) remained significant after logistic regression. Conclusion There was a positive association between hookah smoking and metabolic syndrome, diabetes, obesity and dyslipidemia which was not established in cigarette smoking

Re-conceptualising Territorial Cohesion Through the Prism of Spatial Justice : Critical Perspectives on Academic and Policy Discourses

Peer reviewe