scholarly journals Expanded Tropism and Altered Activation of a Retroviral Glycoprotein Resistant to an Entry Inhibitor Peptide

2006 ◽  
Vol 80 (1) ◽  
pp. 353-359 ◽  
Author(s):  
Sean M. Amberg ◽  
Robert C. Netter ◽  
Graham Simmons ◽  
Paul Bates
Keyword(s):  
Viral Entry ◽  
Terminal Segment ◽  
Heptad Repeat ◽  
Activation Threshold ◽  
Immunodeficiency Virus ◽  
Increased Sensitivity ◽  
Avian Sarcoma ◽  
Hiv 1

ABSTRACT The envelope of class I viruses can be a target for potent viral inhibitors, such as the human immunodeficiency virus type 1 (HIV-1) inhibitor enfuvirtide, which are derived from the C-terminal heptad repeat (HR2) of the transmembrane (TM) subunit. Resistance to an HR2-based peptide inhibitor of a model retrovirus, subgroup A of the Avian Sarcoma and Leukosis Virus genus (ASLV-A), was studied by examining mutants derived by viral passage in the presence of inhibitor. Variants with reduced sensitivity to inhibitor were readily selected in vitro. Sensitivity determinants were identified for 13 different isolates, all of which mapped to the TM subunit. These determinants were identified in two regions: (i) the N-terminal heptad repeat (HR1) and (ii) the N-terminal segment of TM, between the subunit cleavage site and the fusion peptide. The latter class of mutants identified a region outside of the predicted HR2-binding site that can significantly alter sensitivity to inhibitor. A subset of the HR1 mutants displayed the unanticipated ability to infect nonavian cells. This expanded tropism was associated with increased efficiency of envelope triggering by soluble receptor at low temperatures, as measured by protease sensitivity of the surface subunit (SU) of envelope. In addition, expanded tropism was linked for the most readily triggered mutants with increased sensitivity to neutralization by SU-specific antiserum. These observations depict a class of HR2 peptide-selected mutations with a reduced activation threshold, thereby allowing the utilization of alternative receptors for viral entry.

scholarly journals Use of Coreceptors Other Than CCR5 by Non-Syncytium-Inducing Adult and Pediatric Isolates of Human Immunodeficiency Virus Type 1 Is Rare In Vitro

1998 ◽  
Vol 72 (11) ◽  
pp. 9337-9344 ◽  
Author(s):  
Yi-jun Zhang ◽  
Tatjana Dragic ◽  
Yunzhen Cao ◽  
Leondios Kostrikis ◽  
Douglas S. Kwon ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Entry ◽  
Infected Infant ◽  
Subtype B ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT We have tested a panel of pediatric and adult human immunodeficiency virus type 1 (HIV-1) primary isolates for the ability to employ the following proteins as coreceptors during viral entry: CCR1, CCR2b, CCR3, CCR4, CCR5, CCR8, CXCR4, Bonzo, BOB, GPR1, V28, US28, and APJ. Most non-syncytium-inducing isolates could utilize only CCR5. All syncytium-inducing viruses used CXCR4, some also employed V28, and one (DH123) used CCR8 and APJ as well. A longitudinal series of HIV-1 subtype B isolates from an infected infant and its mother utilized Bonzo efficiently, as well as CCR5. The maternal isolates, which were syncytium inducing, also used CXCR4, CCR8, V28, and APJ.

scholarly journals Human Mast Cell Progenitors Can Be Infected by Macrophagetropic Human Immunodeficiency Virus Type 1 and Retain Virus with Maturation In Vitro

2001 ◽  
Vol 75 (22) ◽  
pp. 10808-10814 ◽  
Author(s):  
Norbert Bannert ◽  
Michael Farzan ◽  
Daniel S. Friend ◽  
Hiroshi Ochi ◽  
Kursteen S. Price ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Mast Cell ◽  
Mast Cells ◽  
Cord Blood ◽  
Human Immunodeficiency Virus Type ◽  
Viral Entry ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Mast cells are critical components of innate and adaptive immunity that differentiate in tissues in situ from circulating committed progenitor cells. We now demonstrate that human cord blood-derived mast cell progenitors are susceptible to infection with macrophagetropic (M-tropic) and dualtropic human immunodeficiency virus type 1 (HIV-1) isolates but not with T-cell-tropic (T-tropic) strains. Mast cell progenitors (c-kit + CD13+ cells with chloroacetate esterase activity) were purified from 4-week-old cultures of cord blood mononuclear cells maintained in stem cell factor, interleukin-6 (IL-6), and IL-10 using a CD14 depletion column. These progenitors expressed CCR3, CCR5, and CXCR4, as well as low levels of CD4. When infected in vitro with viruses pseudotyped with different HIV and simian immunodeficiency virus envelope glycoproteins, only M-tropic and dualtropic, but not T-tropic, viruses were able to enter mast cell progenitors. Both the CCR5-specific monoclonal antibody 2D7 and TAK-779, a nonpeptide inhibitor of CCR5-mediated viral entry, blocked HIV-1 strain ADA infection by >80%. Cultures infected with replication-competent virus produced progressively increasing amounts of virus for 21 days as indicated by p24 antigen detection. Mast cell progenitors that were exposed to an M-tropic, green fluorescent protein-expressing HIV-1 strain exhibited fluorescence indicative of viral entry and replication on a single-cell level and retained virus production during differentiation. The trafficking of mast cell progenitors to multiple tissues, combined with the long life span of mature mast cells, suggests that they could provide a widespread and persistent HIV reservoir in AIDS.

scholarly journals Disassembly of Human Immunodeficiency Virus Type 1 Cores In Vitro Reveals Association of Nef with the Subviral Ribonucleoprotein Complex

2003 ◽  
Vol 77 (7) ◽  
pp. 4409-4414 ◽  
Author(s):  
Brett M. Forshey ◽  
Christopher Aiken
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Viral Entry ◽  
Core Stability ◽  
Ribonucleoprotein Complex ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) virulence factor Nef enhances viral infectivity in single-cycle infection assays and accelerates HIV-1 replication in vitro. It has been reported that the effects of Nef are mediated early after viral entry and before the completion of reverse transcription, as viral DNA synthesis is strongly attenuated during infection by Nef-defective virions. Our previous work has demonstrated that Nef is associated with mature HIV-1 cores, implicating Nef in the regulation of HIV-1 core stability. Here we report a comparative analysis of HIV-1 cores isolated from wild-type and Nef-defective particles. We observed no effect of Nef on HIV-1 core structure or stability; however, Nef cosedimented with a subviral ribonucleoprotein complex following dissociation of CA. These results indicate that Nef interacts tightly with an internal component of the HIV-1 core. They further suggest that virion-associated Nef may facilitate an early step in HIV-1 infection following dissociation of the viral capsid in the target cell.

scholarly journals Conserved Salt Bridge between the N- and C-Terminal Heptad Repeat Regions of the Human Immunodeficiency Virus Type 1 gp41 Core Structure Is Critical for Virus Entry and Inhibition

2008 ◽  
Vol 82 (22) ◽  
pp. 11129-11139 ◽  
Author(s):  
Yuxian He ◽  
Shuwen Liu ◽  
Jingjing Li ◽  
Hong Lu ◽  
Zhi Qi ◽  
...  
Keyword(s):  
Viral Entry ◽  
Salt Bridge ◽  
Core Structure ◽  
Heptad Repeat ◽  
Helix Bundle ◽  
Fusion Inhibitors ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Positively Charged

ABSTRACT The fusogenic human immunodeficiency virus type 1 (HIV-1) gp41 core structure is a stable six-helix bundle formed by its N- and C-terminal heptad repeat sequences. Notably, the negatively charged residue Asp632 located at the pocket-binding motif in the C-terminal heptad repeat interacts with the positively charged residue Lys574 in the pocket formation region of the N-terminal heptad repeat to form a salt bridge. We previously demonstrated that the residue Lys574 plays an essential role in six-helix bundle formation and virus infectivity and is a key determinant of the target for anti-HIV fusion inhibitors. In this study, the functionality of residue Asp632 has been specifically characterized by mutational analysis and biophysical approaches. We show that Asp632 substitutions with positively charged residues (D632K and D632R) or a hydrophobic residue (D632V) could completely abolish Env-mediated viral entry, while a protein with a conserved substitution (D632E) retained its activity. Similar to the Lys574 mutations, nonconserved substitutions of Asp632 also severely impaired the α-helicity, stability, and conformation of six-helix bundles as shown by N36 and C34 peptides as a model system. Furthermore, nonconserved substitutions of Asp632 significantly reduced the potency of C34 to sequestrate six-helix bundle formation and to inhibit HIV-1-mediated cell-cell fusion and infection, suggesting its importance for designing antiviral fusion inhibitors. Taken together, these data suggest that the salt bridge between the N- and C-terminal heptad repeat regions of the fusion-active HIV-1 gp41 core structure is critical for viral entry and inhibition.

scholarly journals HMG Protein Family Members Stimulate Human Immunodeficiency Virus Type 1 and Avian Sarcoma Virus Concerted DNA Integration In Vitro

1999 ◽  
Vol 73 (4) ◽  
pp. 2994-3003 ◽  
Author(s):  
Patrick Hindmarsh ◽  
Todd Ridky ◽  
Ray Reeves ◽  
Mark Andrake ◽  
Anna Marie Skalka ◽  
...  
Keyword(s):  
Hmg Proteins ◽  
Dna Integration ◽  
Immunodeficiency Virus ◽  
Sarcoma Virus ◽  
Hmg Protein ◽  
Avian Sarcoma ◽  
Hiv 1

ABSTRACT We have reconstituted concerted human immunodeficiency virus type 1 (HIV-1) integration in vitro with specially designed mini-donor HIV-1 DNA, a supercoiled plasmid acceptor, purified bacterium-derived HIV-1 integrase (IN), and host HMG protein family members. This system is comparable to one previously described for avian sarcoma virus (ASV) (A. Aiyar et al., J. Virol. 70:3571–3580, 1996) that was stimulated by the presence of HMG-1. Sequence analyses of individual HIV-1 integrants showed loss of 2 bp from the ends of the donor DNA and almost exclusive 5-bp duplications of the acceptor DNA at the site of integration. All of the integrants sequenced were inserted into different sites in the acceptor. These are the features associated with integration of viral DNA in vivo. We have used the ASV and HIV-1 reconstituted systems to compare the mechanism of concerted DNA integration and examine the role of different HMG proteins in the reaction. Of the three HMG proteins examined, HMG-1, HMG-2, and HMG-I(Y), the products formed in the presence of HMG-I(Y) for both systems most closely match those observed in vivo. Further analysis of HMG-I(Y) mutants demonstrates that the stimulation of integration requires an HMG-I(Y) domain involved in DNA binding. While complexes containing HMG-I(Y), ASV IN, and donor DNA can be detected in gel shift experiments, coprecipitation experiments failed to demonstrate stable interactions between HMG-I(Y) and ASV IN or between HMG-I(Y) and HIV-1 IN.

scholarly journals The Late-Domain-Containing Protein p6 Is the Predominant Phosphoprotein of Human Immunodeficiency Virus Type 1 Particles

2002 ◽  
Vol 76 (3) ◽  
pp. 1015-1024 ◽  
Author(s):  
Barbara Müller ◽  
Tilo Patschinsky ◽  
Hans-Georg Kräusslich
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Metabolic Labeling ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
A Minor ◽  
Hiv 1

ABSTRACT The Gag-derived protein p6 of human immunodeficiency virus type 1 (HIV-1) plays a crucial role in the release of virions from the membranes of infected cells. It is presumed that p6 and functionally related proteins from other viruses act as adapters, recruiting cellular factors to the budding site. This interaction is mediated by so-called late domains within the viral proteins. Previous studies had suggested that virus release from the plasma membrane shares elements with the cellular endocytosis machinery. Since protein phosphorylation is known to be a regulatory mechanism in these processes, we have investigated the phosphorylation of HIV-1 structural proteins. Here we show that p6 is the major phosphoprotein of HIV-1 particles. After metabolic labeling of infected cells with [ortho- 32P]phosphate, we found that phosphorylated p6 from infected cells and from virus particles consisted of several forms, suggesting differential phosphorylation at multiple sites. Apparently, phosphorylation occurred shortly before or after the release of p6 from Gag and involved only a minor fraction of the total virion-associated p6 molecules. Phosphoamino acid analysis indicated phosphorylation at Ser and Thr, as well as a trace of Tyr phosphorylation, supporting the conclusion that multiple phosphorylation events do occur. In vitro experiments using purified virus revealed that endogenous or exogenously added p6 was efficiently phosphorylated by virion-associated cellular kinase(s). Inhibition experiments suggested that a cyclin-dependent kinase or a related kinase, most likely ERK2, was involved in p6 phosphorylation by virion-associated enzymes.

scholarly journals Ontogeny and Specificities of Mucosal and Blood Human Immunodeficiency Virus Type 1-Specific CD8+ Cytotoxic T Lymphocytes

2003 ◽  
Vol 77 (1) ◽  
pp. 291-300 ◽  
Author(s):  
L. Musey ◽  
Y. Ding ◽  
J. Cao ◽  
J. Lee ◽  
C. Galloway ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cytotoxic T Lymphocyte ◽  
Infected Individual ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Induction of adaptive immunity to human immunodeficiency virus type 1 (HIV-1) at the mucosal site of transmission is poorly understood but crucial in devising strategies to control and prevent infection. To gain further understanding of HIV-1-specific T-cell mucosal immunity, we established HIV-1-specific CD8+ cytotoxic T-lymphocyte (CTL) cell lines and clones from the blood, cervix, rectum, and semen of 12 HIV-1-infected individuals and compared their specificities, cytolytic function, and T-cell receptor (TCR) clonotypes. Blood and mucosal CD8+ CTL had common HIV-1 epitope specificities and major histocompatibility complex restriction patterns. Moreover, both systemic and mucosal CTL lysed targets with similar efficiency, primarily through the perforin-dependent pathway in in vitro studies. Sequence analysis of the TCRβ VDJ region revealed in some cases identical HIV-1-specific CTL clones in different compartments in the same HIV-1-infected individual. These results clearly establish that a subset of blood and mucosal HIV-1-specific CTL can have a common origin and can traffic between anatomically distinct compartments. Thus, these effectors can provide immune surveillance at the mucosa, where rapid responses are needed to contain HIV-1 infection.

scholarly journals Gag sequence variation in a human immunodeficiency virus type 1 transmission cluster influences viral replication fitness

2013 ◽  
Vol 94 (2) ◽  
pp. 354-359 ◽  
Author(s):  
Esther F. Gijsbers ◽  
Ad C. van Nuenen ◽  
Hanneke Schuitemaker ◽  
Neeltje A. Kootstra
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Sequence Variation ◽  
Clinical Course ◽  
Immunodeficiency Virus ◽  
Compensatory Mutations ◽  
Replication Fitness ◽  
Hiv 1

Three men from a proven homosexual human immunodeficiency virus type 1 (HIV-1) transmission cluster showed large variation in their clinical course of infection. To evaluate the effect of evolution of the same viral variant in these three patients, we analysed sequence variation in the capsid protein and determined the impact of the observed variation on viral replication fitness in vitro. Viral gag sequences from all three patients contained a mutation at position 242, T242N or T242S, which have been associated with lower virus replication in vitro. Interestingly, HIV-1 variants from patients with a progressive clinical course of infection developed compensatory mutations within the capsid that restored viral fitness, instead of reversion of the T242S mutation. In HIV-1 variants from patient 1, an HLA-B57+ elite controller, no compensatory mutations emerged during follow-up.

scholarly journals In Vitro Antiviral Activity and Cross-Resistance Profile of PL-100, a Novel Protease Inhibitor of Human Immunodeficiency Virus Type 1

2007 ◽  
Vol 51 (11) ◽  
pp. 4036-4043 ◽  
Author(s):  
Serge Dandache ◽  
Guy Sévigny ◽  
Jocelyn Yelle ◽  
Brent R. Stranix ◽  
Neil Parkin ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiviral Activity ◽  
Highly Active Antiretroviral Therapy ◽  
Cross Resistance ◽  
Drug Resistant ◽  
Resistance Profile ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Despite the success of highly active antiretroviral therapy, the current emergence and spread of drug-resistant variants of human immunodeficiency virus (HIV) stress the need for new inhibitors with distinct properties. We designed, produced, and screened a library of compounds based on an original l-lysine scaffold for their potentials as HIV type 1 (HIV-1) protease inhibitors (PI). One candidate compound, PL-100, emerged as a specific and noncytotoxic PI that exhibited potent inhibition of HIV-1 protease and viral replication in vitro (Ki , ∼36 pM, and 50% effective concentration [EC50], ∼16 nM, respectively). To confirm that PL-100 possessed a favorable resistance profile, we performed a cross-resistance study using a panel of 63 viral strains from PI-experienced patients selected for the presence of primary PI mutations known to confer resistance to multiple PIs now in clinical use. The results showed that PL-100 retained excellent antiviral activity against almost all of these PI-resistant viruses and that its performance in this regard was superior to those of atazanavir, amprenavir, indinavir, lopinavir, nelfinavir, and saquinavir. In almost every case, the increase in the EC50 for PL-100 observed with viruses containing multiple mutations in protease was far less than that obtained with the other drugs tested. These data underscore the potential for PL-100 to be used in the treatment of drug-resistant HIV disease and argue for its further development.

Sign in / Sign up

Export Citation Format

Share Document