P80 Natural Essence Exerts Efficient Anti-HIV-1- as Well as Adjuvant Effects in DCs

Dendritic cells (DCs), as well as complement, play a major role during human immunodeficiency virus 1 (HIV-1) entry and infection at mucosal sites. Together, DCs and complement are key points for understanding host defence against HIV-1 infection and for studying the impact of new drugs on the regulation of innate host-pathogen interactions and adaptive immunity. For this, we evaluated the antiviral effect of the P80 natural essence (Longan extract) on interactions of non- and complement-opsonized HIV-1 with DCs. In viability assays, we first illustrated the effects of P80 natural essence on DC function. We found that P80 concentrations above 1.5% caused increased cell death, while at concentrations between 0.5% and 1% the compound exerted efficient antiviral effects in DCs and illustrated an adjuvant effect regarding DC activation. DC maturation, as well as co-stimulatory capacity, were significantly improved by P80 natural essence via p38 MAPK phosphorylation in presence of the viral challenge independent of the opsonization pattern. These findings might be exploited for future therapeutic options to target DC subsets directly at mucosal sites by P80 natural essence and to block entry of both, non- and complement-opsonized HIV-1.

Download Full-text

The antiviral factor APOBEC3G improves CTL recognition of cultured HIV-infected T cells

Journal of Experimental Medicine ◽

10.1084/jem.20091933 ◽

2009 ◽

Vol 207 (1) ◽

pp. 39-49 ◽

Cited By ~ 63

Author(s):

Nicoletta Casartelli ◽

Florence Guivel-Benhassine ◽

Romain Bouziat ◽

Samantha Brandler ◽

Olivier Schwartz ◽

...

Keyword(s):

Cytidine Deaminase ◽

Adaptive Immune System ◽

Antiviral Effect ◽

Inhibitory Effect ◽

Hiv Replication ◽

Viral Infectivity Factor ◽

Cellular Immune ◽

Vif Protein ◽

The Impact ◽

Hiv 1

The cytidine deaminase APOBEC3G (A3G) enzyme exerts an intrinsic anti–human immunodeficiency virus (HIV) defense by introducing lethal G-to-A hypermutations in the viral genome. The HIV-1 viral infectivity factor (Vif) protein triggers degradation of A3G and counteracts this antiviral effect. The impact of A3G on the adaptive cellular immune response has not been characterized. We examined whether A3G-edited defective viruses, which are known to express truncated or misfolded viral proteins, activate HIV-1–specific (HS) CD8+ cytotoxic T lymphocytes (CTLs). To this end, we compared the immunogenicity of cells infected with wild-type or Vif-deleted viruses in the presence or absence of the cytidine deaminase. The inhibitory effect of A3G on HIV replication was associated with a strong activation of cocultivated HS-CTLs. CTL activation was particularly marked with Vif-deleted HIV and with viruses harboring A3G. Enzymatically inactive A3G mutants failed to enhance CTL activation. We also engineered proviruses bearing premature stop codons in their genome as scars of A3G editing. These viruses were not infectious but potently activated HS-CTLs. Therefore, the pool of defective viruses generated by A3G represents an underestimated source of viral antigens. Our results reveal a novel function for A3G, acting not only as an intrinsic antiviral factor but also as an inducer of the adaptive immune system.

Download Full-text

Upregulation of human immunodeficiency virus-1 in chronically infected monocytic cell line by both contact with endothelial cells and cytokines

Blood ◽

10.1182/blood.v84.5.1567.1567 ◽

1994 ◽

Vol 84 (5) ◽

pp. 1567-1572 ◽

Cited By ~ 24

Author(s):

ST Fan ◽

K Hsia ◽

TS Edgington

Keyword(s):

Human Immunodeficiency Virus ◽

Endothelial Cells ◽

Viral Gene ◽

Target Cells ◽

Monocytic Cell ◽

Monocytic Cell Line ◽

Immunodeficiency Virus ◽

The Impact ◽

Hiv 1

Abstract Cells of monocytic lineage (Mo) persistently infected with human immunodeficiency virus (HIV) have been suspected to be a major reservoir for in vivo transmission of virus to susceptible target cells. Cellular events and mechanisms that upregulate viral gene expression in such cells are important issues. Because the traffic of such cells is central to biodistribution of HIV, we have explored the impact of interaction of endothelium with HIV-1-infected U1 promonocytic cells. Coculturing of U1 with human umbilical endothelial cells (HUVEC) for 24 to 72 hours in the absence of stimulation induced HIV-1 p24 biosynthesis significantly. Antibody-blocking experiments indicated that CD11/CD18 integrins play a role in upregulation of HIV expression elicited by interaction with HUVEC. Engagement of CD11b/CD18 by adherence of U1 to surfaces coated with either the cognate ligand fibrinogen or monoclonal antibody specific for CD11b/CD18 also enhanced p24 biosynthesis. Furthermore, endothelial cells were found to constitutively synthesize and secrete soluble factors that enhanced HIV- 1 synthesis. The enhancing factors, of estimated size 10 to 45 kD, were induced in HUVEC to high levels by monokines or by lipopolysaccharide, resulting in markedly enhanced HIV-1 expression by U1. These endothelial cell-derived HIV-1-enhancing factors consist of, among others, interleukin-6 (IL-6), IL-1 beta, and granulocyte-macrophage CSF (GM-CSF). Our results suggest that activation of HIV biosynthesis in infected Mo via interaction with endothelium may impact significantly on the tissue distribution and pathogenesis of HIV infections.

Download Full-text

Flow Cytometry Analysis of HIV-1 Env Conformations at the Surface of Infected Cells and Virions: Role of Nef, CD4, and SERINC5

Journal of Virology ◽

10.1128/jvi.01783-19 ◽

2019 ◽

Vol 94 (6) ◽

Cited By ~ 3

Author(s):

Isabelle Staropoli ◽

Jérémy Dufloo ◽

Anaïs Ducher ◽

Pierre-Henri Commere ◽

Anna Sartori-Rupp ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Cellular Proteins ◽

Viral Infectivity ◽

Viral Particles ◽

Immunodeficiency Virus ◽

Infected Cells ◽

Env Protein ◽

The Impact ◽

Hiv 1

ABSTRACT The HIV-1 Env protein is exposed at the surface of virions and infected cells. Env fluctuates between different closed and open structural states and these conformations influence both viral infectivity and sensitivity to antibody binding and neutralization. We established a flow virometry assay to visualize Env proteins at the surface of human immunodeficiency virus type 1 (HIV-1) virions. The assay is performed on ultracentrifuged fluorescent viral particles that are stained with a panel of broadly neutralizing antibodies (bNAbs) and nonneutralizing antibodies (nnAbs) that probe different epitopes of Env. We used this assay to compare Env at the surface of producer cells and viral particles and to analyze the effect of Nef, CD4, and SERINC5 on Env accessibility to antibodies. We studied the laboratory-adapted strain NL4-3 and two transmitted/founder viruses, THRO and CH058. We confirm that antibody accessibility varies between viral strains and show that Nef, CD4, and SERINC5 additively impact Env conformations. We further demonstrate that the Env accessibility profile on virions is globally similar to that observed on HIV-1-infected cells, with some noticeable differences. For instance, nnAbs bind to virions more efficiently than to producer cells, likely reflecting changes in Env conformational states on mature viral particles. This test complements other techniques and provides a convenient and simple tool for quantifying and probing the structure of Env at the virion surface and to analyze the impact of viral and cellular proteins on these parameters. IMPORTANCE HIV-1 Env conformation is one of the key parameters determining viral infectivity. The flow virometry-based assay developed in this study allows for the characterization of proteins incorporated in HIV-1 particles. We studied the conformation of HIV-1 Env and the impact that the viral protein Nef and the cellular proteins CD4 and SERINC5 have on Env accessibility to antibodies. Our assay permitted us to highlight some noticeable differences in the conformation of Env between producer cells and viral particles. It contributes to a better understanding of the actual composition of HIV-1 particles.

Download Full-text

Evolution of the human immunodeficiency virus type 1 protease: effects on viral replication capacity and protease robustness

Journal of General Virology ◽

10.1099/vir.0.045492-0 ◽

2012 ◽

Vol 93 (12) ◽

pp. 2625-2634 ◽

Cited By ~ 6

Author(s):

Elena Capel ◽

Glòria Martrus ◽

Mariona Parera ◽

Bonaventura Clotet ◽

Miguel Angel Martínez

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Replication Capacity ◽

Recombinant Viruses ◽

Subtype B ◽

Immunodeficiency Virus ◽

The Impact ◽

Hiv 1

The rapid spread of human immunodeficiency virus type 1 (HIV-1) in humans has been accompanied by continuous extensive genetic diversification of the virus. The aim of this study was to investigate the impact of HIV-1 diversification on HIV-1 replication capacity (RC) and mutational robustness. Thirty-three HIV-1 protease sequences were amplified from three groups of viruses: two naïve sample groups isolated 15 years apart plus a third group of protease inhibitor-(PI) resistant samples. The amplified proteases were recombined with an HXB2 infectious clone and RC was determined in MT-4 cells. RC was also measured in these three groups after random mutagenesis in vitro using error-prone PCR. No significant RC differences were observed between recombinant viruses from either early or recent naïve isolates (P = 0.5729), even though the proteases from the recent isolates had significantly lower sequence conservation scores compared with a subtype B ancestral sequence (P<0.0001). Randomly mutated recombinant viruses from the three groups exhibited significantly lower RC values than the corresponding wild-type viruses (P<0.0001). There was no significant difference regarding viral infectivity reduction between viruses carrying randomly mutated naïve proteases from early or recent sample isolates (P = 0.8035). Interestingly, a significantly greater loss of RC was observed in the PI-resistant protease group (P = 0.0400). These results demonstrate that protease sequence diversification has not affected HIV-1 RC or protease robustness and indicate that proteases carrying PI resistance substitutions are less robust than naïve proteases.

Download Full-text

A Dual Infection/Competition Assay Shows a Correlation between Ex Vivo Human Immunodeficiency Virus Type 1 Fitness and Disease Progression

Journal of Virology ◽

10.1128/jvi.74.19.9222-9233.2000 ◽

2000 ◽

Vol 74 (19) ◽

pp. 9222-9233 ◽

Cited By ~ 186

Author(s):

Miguel E. Quiñones-Mateu ◽

Sarah C. Ball ◽

Andre J. Marozsan ◽

Vincent S. Torre ◽

Jamie L. Albright ◽

...

Keyword(s):

Immune Response ◽

Human Immunodeficiency Virus ◽

Disease Progression ◽

Ex Vivo ◽

Relative Fitness ◽

Immunodeficiency Virus ◽

The Impact ◽

Hiv 1

ABSTRACT This study was designed to examine the impact of human immunodeficiency virus type 1 (HIV-1) fitness on disease progression through the use of a dual competition/heteroduplex tracking assay (HTA). Despite numerous studies on the impact of HIV-1 diversity and HIV-specific immune response on disease progression, we still do not have a firm understanding of the long-term pathogenesis of this virus. Strong and early CD8-positive cytotoxic T-cell and CD4-positive T-helper cell responses directed toward HIV-infected cells appear to curb HIV pathogenesis. However, the rate at which the virus infects the CD4+ T-cell population and possibly destroys the HIV-specific immune response may also alter the rate of disease progression. For HIV-1 fitness studies, we established conditions for dual HIV-1 infections of peripheral blood mononuclear cells (PBMC) and a sensitive HTA to measure relative virus production. A pairwise comparison was then performed to estimate the relative fitness of various non-syncytium-inducing/CCR5-tropic (NSI/R5) and syncytium-inducing/CXCR4-tropic (SI/X4) HIV-1 isolates. Four HIV-1 strains (two NSI/R5 and two SI/X4) with moderate ex vivo fitness were then selected as controls and competed against primary HIV-1 isolates from an HIV-infected Belgian cohort. HIV-1 isolates from long-term survivors (LTS) were outcompeted by control strains and were significantly less fit than HIV-1 isolates from patients with accelerated progression to AIDS (PRO). In addition, NSI/R5 HIV-1 isolates from PRO overgrew control SI/X4 strains, suggesting that not all SI/X4 HIV-1 isolates replicate more efficiently than all NSI/R5 isolates. Finally, there were strong, independent correlations between viral load and the total relative fitness values of HIV-1 isolates from PRO (r = 0.84, P = 0.033) and LTS (r = 0.86, P = 0.028). Separation of the PRO and LTS plots suggest that HIV-1 fitness together with viral load may be a strong predictor for the rate of disease progression.

Download Full-text

Native Conformation and Canonical Disulfide Bond Formation Are Interlinked Properties of HIV-1 Env Glycoproteins

Journal of Virology ◽

10.1128/jvi.01953-15 ◽

2015 ◽

Vol 90 (6) ◽

pp. 2884-2894 ◽

Cited By ~ 17

Author(s):

Eden P. Go ◽

Albert Cupo ◽

Rajesh Ringe ◽

Pavel Pugach ◽

John P. Moore ◽

...

Keyword(s):

Disulfide Bond ◽

Disulfide Bonds ◽

Protein A ◽

Native Conformation ◽

Purification Method ◽

Immunodeficiency Virus ◽

Monomeric Gp120 ◽

Env Protein ◽

The Impact ◽

Hiv 1

ABSTRACTWe investigated whether there is any association between a native-like conformation and the presence of only the canonical (i.e., native) disulfide bonds in the gp120 subunits of a soluble recombinant human immunodeficiency virus type 1 (HIV-1) envelope (Env) glycoprotein. We used a mass spectrometry (MS)-based method to map the disulfide bonds present in nonnative uncleaved gp140 proteins and native-like SOSIP.664 trimers based on the BG505envgene. Our results show that uncleaved gp140 proteins were not homogeneous, in that substantial subpopulations (20 to 80%) contained aberrant disulfide bonds. In contrast, the gp120 subunits of the native-like SOSIP.664 trimer almost exclusively retained the canonical disulfide bond pattern. We also observed that the purification method could influence the proportion of an Env protein population that contained aberrant disulfide bonds. We infer that gp140 proteins may always contain a variable but substantial proportion of aberrant disulfide bonds but that the impact of this problem can be minimized via design and/or purification strategies that yield native-like trimers. The same factors may also be relevant to the production and purification of monomeric gp120 proteins that are free of aberrant disulfide bonds.IMPORTANCEIt is widely thought that a successful HIV-1 vaccine will include a recombinant form of the Env protein, a trimer located on the virion surface. To increase yield and simplify purification, Env proteins are often made in truncated, soluble forms. A consequence, however, can be the loss of the native conformation concomitant with the virion-associated trimer. Moreover, some soluble recombinant Env proteins contain aberrant disulfide bonds that are not expected to be present in the native trimer. To assess whether these observations are linked, to determine the extent of disulfide bond scrambling, and to understand why scrambling occurs, we determined the disulfide bond profiles of two soluble Env proteins with different designs that are being assessed as vaccine candidates. We found that uncleaved gp140 forms heterogeneous mixtures in which aberrant disulfide bonds abound. In contrast, BG505 SOSIP.664 trimers are more homogeneous, native-like entities that contain predominantly the native disulfide bond profile.

Download Full-text

Interaction between the Human Immunodeficiency Virus Type 1 Gag Matrix Domain and Phosphatidylinositol-(4,5)-Bisphosphate Is Essential for Efficient Gag Membrane Binding

Journal of Virology ◽

10.1128/jvi.01614-07 ◽

2007 ◽

Vol 82 (5) ◽

pp. 2405-2417 ◽

Cited By ~ 168

Author(s):

Vineela Chukkapalli ◽

Ian B. Hogue ◽

Vitaly Boyko ◽

Wei-Shau Hu ◽

Akira Ono

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Molecular Mechanisms ◽

Membrane Binding ◽

Particle Assembly ◽

Immunodeficiency Virus ◽

The Impact ◽

Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) particle assembly mediated by the viral structural protein Gag occurs predominantly on the plasma membrane (PM). Although it is known that the matrix (MA) domain of Gag plays a major role in PM localization, molecular mechanisms that determine the location of assembly remain to be elucidated. We observed previously that overexpression of polyphosphoinositide 5-phosphatase IV (5ptaseIV) that depletes PM phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2] impairs virus particle production and redirects processed Gag to intracellular compartments. In this study, we examined the impact of PI(4,5)P2 depletion on the subcellular localization of the entire Gag population using Gag-fluorescent protein chimeras. Upon 5ptaseIV overexpression, in addition to perinuclear localization, Gag also showed a hazy cytosolic signal, suggesting that PI(4,5)P2 depletion impairs Gag membrane binding. Indeed, Gag was less membrane bound in PI(4,5)P2-depleted cells, as assessed by biochemical analysis. These observations are consistent with the hypothesis that Gag interacts with PI(4,5)P2. To examine a putative Gag interaction with PI(4,5)P2, we developed an in vitro binding assay using full-length myristoylated Gag and liposome-associated PI(4,5)P2. Using this assay, we observed that PI(4,5)P2 significantly enhances liposome binding of wild-type Gag. In contrast, a Gag derivative lacking MA did not require PI(4,5)P2 for efficient liposome binding. To analyze the involvement of MA in PI(4,5)P2 binding further, we examined MA basic amino acid substitution mutants. These mutants, previously shown to localize in perinuclear compartments, bound PI(4,5)P2-containing liposomes weakly. Altogether, these results indicate that HIV-1 Gag binds PI(4,5)P2 on the membrane and that the MA basic domain mediates this interaction.

Download Full-text

Relative roles of signals upstream of AAUAAA and promoter proximity in regulation of human immunodeficiency virus type 1 mRNA 3' end formation.

Molecular and Cellular Biology ◽

10.1128/mcb.12.12.5555 ◽

1992 ◽

Vol 12 (12) ◽

pp. 5555-5562 ◽

Cited By ~ 15

Author(s):

J D DeZazzo ◽

J M Scott ◽

M J Imperiale

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Dependent Manner ◽

Immunodeficiency Virus ◽

A Site ◽

The Impact ◽

Hiv 1 ◽

Rna Levels

At least two mechanisms have been implicated in regulating poly(A) site use in human immunodeficiency virus type 1 (HIV-1): inhibition of basal signals within 500 nucleotides (nt) of the cap site, leading to specific suppression of the 5' poly(A) site, and stimulation of basal signals by long terminal repeat U3 sequences, leading to specific activation of the 3' poly(A) site. We determined the relative contributions of these mechanisms in a HeLa cell transcription/processing reaction and by transient transfection analysis. In vitro, the efficiency of basal signals is equivalent close to (270 nt) and far from (1,080 nt) the promoter and is stimulated at least 30-fold in both positions by upstream U3 sequences. In vivo, U3 sequences also enhance processing at both positions. There are two additional effects when the poly(A) site is close to the cap site: at least a 15-fold reduction in total RNA levels and a 5-fold decrease in relative levels of RNA processed at the HIV-1 site in constructs containing U3. Both effects are overcome by insertion of upstream splicing signals in an orientation-dependent manner. Splicing appears to influence poly(A)+ RNA levels by two distinct mechanisms: stabilizing nuclear transcripts and directly stimulating 3' end formation. It is proposed that upstream elements play major roles in regulating poly(A) site choice and in controlling the subsequent fate of polyadenylated RNA. The impact of these findings on mechanisms of mRNA biogenesis in the HIV-1 provirus is discussed.

Download Full-text

Cross-Reactions between the Cytotoxic T-Lymphocyte Responses of Human Immunodeficiency Virus-Infected African and European Patients

Journal of Virology ◽

10.1128/jvi.72.5.3547-3553.1998 ◽

1998 ◽

Vol 72 (5) ◽

pp. 3547-3553 ◽

Cited By ~ 58

Author(s):

Deniz Durali ◽

Jacques Morvan ◽

Franck Letourneur ◽

Doris Schmitt ◽

Nelly Guegan ◽

...

Keyword(s):

Immune Response ◽

Human Immunodeficiency Virus ◽

T Lymphocyte ◽

Recombinant Virus ◽

Cytotoxic T Lymphocyte ◽

Target Cells ◽

Cross Reactions ◽

Immunodeficiency Virus ◽

The Impact ◽

Hiv 1

ABSTRACT The great variability of protein sequences from human immunodeficiency virus (HIV) type 1 (HIV-1) isolates represents a major obstacle to the development of an effective vaccine against this virus. The surface protein (Env), which is the predominant target of neutralizing antibodies, is particularly variable. Here we examine the impact of variability among different HIV-1 subtypes (clades) on cytotoxic T-lymphocyte (CTL) activities, the other major component of the antiviral immune response. CTLs are produced not only against Env but also against other structural proteins, as well as some regulatory proteins. The genetic subtypes of HIV-1 were determined for Env and Gag from several patients infected either in France or in Africa. The cross-reactivities of the CTLs were tested with target cells expressing selected proteins from HIV-1 isolates of clade A or B or from HIV type 2 isolates. All African patients were infected with viruses belonging to clade A for Env and for Gag, except for one patient who was infected with a clade A Env-clade G Gag recombinant virus. All patients infected in France were infected with clade B viruses. The CTL responses obtained from all the African and all the French individuals tested showed frequent cross-reactions with proteins of the heterologous clade. Epitopes conserved between the viruses of clades A and B appeared especially frequent in Gag p24, Gag p18, integrase, and the central region of Nef. Cross-reactivity also existed among Gag epitopes of clades A, B, and G, as shown by the results for the patient infected with the clade A Env-clade G Gag recombinant virus. These results show that CTLs raised against viral antigens from different clades are able to cross-react, emphasizing the possibility of obtaining cross-immunizations for this part of the immune response in vaccinated individuals.

Download Full-text

The Impact of Individual Human Immunodeficiency Virus Type 1 Protease Mutations on Drug Susceptibility Is Highly Influenced by Complex Interactions with the Background Protease Sequence

Journal of Virology ◽

10.1128/jvi.00291-09 ◽

2009 ◽

Vol 83 (18) ◽

pp. 9512-9520 ◽

Cited By ~ 12

Author(s):

H. Van Marck ◽

I. Dierynck ◽

G. Kraus ◽

S. Hallenberger ◽

T. Pattery ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Drug Susceptibility ◽

Vast Number ◽

Complex Interactions ◽

Immunodeficiency Virus ◽

The Impact ◽

Hiv 1

ABSTRACT The requirement for multiple mutations for protease inhibitor (PI) resistance necessitates a better understanding of the molecular basis of resistance development. The novel bioinformatics resistance determination approach presented here elaborates on genetic profiles observed in clinical human immunodeficiency virus type 1 (HIV-1) isolates. Synthetic protease sequences were cloned in a wild-type HIV-1 background to generate a large number of close variants, covering 69 mutation clusters between multi-PI-resistant viruses and their corresponding genetically closely related, but PI-susceptible, counterparts. The vast number of mutants generated facilitates a profound and broad analysis of the influence of the background on the effect of individual PI resistance-associated mutations (PI-RAMs) on PI susceptibility. Within a set of viruses, all PI-RAMs that differed between susceptible and resistant viruses were varied while maintaining the background sequence from the resistant virus. The PI darunavir was used to evaluate PI susceptibility. Single sets allowed delineation of the impact of individual mutations on PI susceptibility, as well as the influence of PI-RAMs on one another. Comparing across sets, it could be inferred how the background influenced the interaction between two mutations, in some cases even changing antagonistic relationships into synergistic ones or vice versa. The approach elaborates on patient data and demonstrates how the specific mutational background greatly influences the impact of individual mutations on PI susceptibility in clinical patterns.

Download Full-text