Rapid Prescreening for Antiviral Agents against HIV-1 Based on Their Inhibitory Activity in Site-Directed Immunoassays. Approaches Applicable to Epidemic HIV-1 Strains

Several compounds, including the triphenylmethane derivative aurintricarboxylic acid (ATA) and porphyrins, were reported to inhibit the binding of anti-V3 loop-specific antibodies to the V3 loop of gp120 from HIV-1 III-B and to have antiviral activity, probably due to interference with the biological function of the V3 loop. However, these compounds can be applied to antiviral chemotherapy only if they interact with envelope glycoproteins from a multitude of epidemic HIV-1 strains and inhibit their replication. Since recombinant envelope glycoproteins, synthetic peptides and anti-V3 monoclonal antibodies may not be available for these HIV-1 strains, alternative assays are needed to prescreen different compounds for potential antiviral activity against these viruses. Results presented here indicate that: (1) virions of HIV-1 MN, most closely related to primary HIV-1 isolates from European and North American countries, and human anti-HIV-1 antibodies, can also be used for rapid prescreening of antiviral agents, (2) compounds with antiviral activity against HIV-1 MN, discerned by site-directed immunoassays, inhibited the reaction of human anti-HIV-1 with a V3 loop consensus peptide corresponding to European/North American HIV-1 isolates, and (3) meso-tetra (4-carboxyphenyl) porphine (MTCPP), one of the most potent inhibitors of HIV-1 replication selected on the basis of site-directed immunoassays, preferentially attached to the V3 loop of gp120.

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Rapid Prescreening for Antiviral Agents against HIV-1 Based on Their Inhibitory Activity in Site-Directed Immunoassays. II. Porphyrins Reacting with the V3 Loop of gp120

Antiviral Chemistry and Chemotherapy ◽

10.1177/095632029200300108 ◽

1992 ◽

Vol 3 (1) ◽

pp. 55-63 ◽

Cited By ~ 23

Author(s):

A. R. Neurath ◽

N. Strick ◽

P. Haberfield ◽

S. Jiang

Keyword(s):

Antiviral Activity ◽

Inhibitory Activity ◽

Antiviral Agents ◽

V3 Loop ◽

Antiviral Compounds ◽

Porphyrin Derivatives ◽

Immunodeficiency Virus ◽

Glycoprotein Gp120 ◽

The Relationship ◽

Hiv 1

Recent observations that haernin inhibited the replication of the human immunodeficiency virus (HIV-1) and the reaction between the HIV-1 envelope glycoprotein gp120 and antibodies specific for the V3 hypervariable loop of this glycoprotein were an enticement to determine whether or not additional porphyrins had similar activities. Several porphyrin derivatives, particularly meso-tetra (4-carboxyphenyl) porphine, were more potent inhibitors of HIV-1 replication than haernin. They blocked the binding of homologous antibodies to synthetic peptides corresponding to V3 hypervariable loops of 21 distinct HIV-1 isolates, and inhibited the replication in lymphocytic (MT-2) and promonocyte (U937) cell lines of several HIV-1 isolates, tested (IIIB, RF, SF-2, and MN). Compounds with inhibitory activity had a tetrapyrrole ring and, carboxyl or sulphonate groups. However, antiviral activity depended on minor structural difference's between distinct derivatives endowed with these two features. Metalloporphyrins had a drastically reduced antiviral activity in comparison with the corresponding porphyrins. An understanding of the relationship between the structure of porphyrins and their antiviral effects, perceptible from the results presented, is expected to lead to the design of additional derivatives with more potent antiviral activity and to unravelling of molecular details involved in the association between the V3 loop of gp120 and antiviral compounds targeted to this loop.

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Cell-Based and Biochemical Analysis of the anti-HIV Activity of Combinations of 3′-azido-3′-deoxythymidine and Analogues of TIBO

Antiviral Chemistry and Chemotherapy ◽

10.1177/095632029400500105 ◽

1994 ◽

Vol 5 (1) ◽

pp. 35-42 ◽

Cited By ~ 15

Author(s):

R. W. Buckheit ◽

E. L. White ◽

J. Germany-Decker ◽

L. B. Allen ◽

L. J. Ross ◽

...

Keyword(s):

Cell Culture ◽

Reverse Transcriptase ◽

Biochemical Analysis ◽

Therapeutic Strategy ◽

Antiviral Agents ◽

Antiviral Chemotherapy ◽

The Individual ◽

Secondary Mechanism ◽

Anti Hiv ◽

Hiv 1

The toxicity of 3′-azido-3′-deoxythymidine (AZT) and the appearance of drug-resistant mutants in patients treated with AZT emphasizes the critical importance of the development of alternative strategies for the therapy of AIDS patients. Combination antiviral chemotherapy provides an attractive therapeutic strategy since the dose of the individual agents may be lowered to reduce toxicity and the use of two potent antiviral agents may limit the development of drug resistance. Two analogues of tetrahydro-imidazo[4,5,1-jk][1,4]-benzodiazepin-2(1H)-thione (TIBO) potently and selectively inhibit the replication of HIV-1 in cell culture. In combination with AZT, either of the two TIBO compounds, R82913 and R86183, was highly synergistic in cell culture against HIV-1. However, in biochemical enzyme inhibition assays, utilizing recombinant HIV-1 reverse transcriptase, synergy was not detected at the enzymatic level. These results suggest that one of these two known inhibitors of HIV-1 reverse transcriptase may have a secondary mechanism of action distinct from inhibition of the reverse transcriptase.

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A V3 Loop-Dependent gp120 Element Disrupted by CD4 Binding Stabilizes the Human Immunodeficiency Virus Envelope Glycoprotein Trimer

Journal of Virology ◽

10.1128/jvi.02587-09 ◽

2010 ◽

Vol 84 (7) ◽

pp. 3147-3161 ◽

Cited By ~ 53

Author(s):

Shi-Hua Xiang ◽

Andrés Finzi ◽

Beatriz Pacheco ◽

Kevin Alexander ◽

Wen Yuan ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Receptor Binding ◽

Chemokine Receptor ◽

Chemokine Receptors ◽

Envelope Glycoproteins ◽

V3 Loop ◽

Virus Envelope ◽

Hydrophobic Patch ◽

Immunodeficiency Virus ◽

Hiv 1

ABSTRACT Human immunodeficiency virus (HIV-1) entry into cells is mediated by a trimeric complex consisting of noncovalently associated gp120 (exterior) and gp41 (transmembrane) envelope glycoproteins. The binding of gp120 to receptors on the target cell alters the gp120-gp41 relationship and activates the membrane-fusing capacity of gp41. Interaction of gp120 with the primary receptor, CD4, results in the exposure of the gp120 third variable (V3) loop, which contributes to binding the CCR5 or CXCR4 chemokine receptors. We show here that insertions in the V3 stem or polar substitutions in a conserved hydrophobic patch near the V3 tip result in decreased gp120-gp41 association (in the unliganded state) and decreased chemokine receptor binding (in the CD4-bound state). Subunit association and syncytium-forming ability of the envelope glycoproteins from primary HIV-1 isolates were disrupted more by V3 changes than those of laboratory-adapted HIV-1 envelope glycoproteins. Changes in the gp120 β2, β19, β20, and β21 strands, which evidence suggests are proximal to the V3 loop in unliganded gp120, also resulted in decreased gp120-gp41 association. Thus, a gp120 element composed of the V3 loop and adjacent beta strands contributes to quaternary interactions that stabilize the unliganded trimer. CD4 binding dismantles this element, altering the gp120-gp41 relationship and rendering the hydrophobic patch in the V3 tip available for chemokine receptor binding.

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Synthesis and Antiviral Activity of 1,3-Disubstituted Uracils against HIV-1 and HCMV

Antiviral Chemistry and Chemotherapy ◽

10.1177/095632020301400506 ◽

2003 ◽

Vol 14 (5) ◽

pp. 271-279 ◽

Cited By ~ 15

Author(s):

Tokumi Maruyama ◽

Shigetada Kozai ◽

Tetsuo Yamasaki ◽

Myriam Witvrouw ◽

Christophe Pannecouque ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Antiviral Activity ◽

Human Cytomegalovirus ◽

Therapeutic Agents ◽

Reverse Transcriptase Inhibitors ◽

Uracil Derivatives ◽

Immunodeficiency Virus ◽

Anti Hiv Agents ◽

Anti Hiv ◽

Hiv 1

The development of new non-nucleoside reverse transcriptase inhibitors (NNRTIs) is an efficient strategy for finding new therapeutic agents against human immunodeficiency virus (HIV). A large number of 6-substituted uracil derivatives have been prepared in order to explore new NNRTIs. However, there are few approaches to anti-HIV agents from 1,3-disubstituted uracil derivatives. Therefore, we tried to prepare several 1,3-disubstituted uracils, which were easily obtainable from uracil by preparation under alkali and Mitsunobu conditions, and examined their antiviral activity against HIV-1 and human cytomegalovirus (HCMV). We found that 1-benzyl-3-(3,5-dimethylbenzyl)uracil and 1-cyanomethyl-3-(3,5-dimethylbenzyl)-4-thiouracil showed powerful inhibition against HCMV and HIV-1, respectively.

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In Vitro Antiviral Activity of the Novel, Tyrosyl-Based Human Immunodeficiency Virus (HIV) Type 1 Protease Inhibitor Brecanavir (GW640385) in Combination with Other Antiretrovirals and against a Panel of Protease Inhibitor-Resistant HIV

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00401-07 ◽

2007 ◽

Vol 51 (9) ◽

pp. 3147-3154 ◽

Cited By ~ 23

Author(s):

Richard Hazen ◽

Robert Harvey ◽

Robert Ferris ◽

Charles Craig ◽

Phillip Yates ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Antiviral Activity ◽

Protease Inhibitor ◽

Reverse Transcriptase ◽

In Vitro Assays ◽

Immunodeficiency Virus ◽

Anti Hiv ◽

Hiv 1

ABSTRACT Brecanavir, a novel tyrosyl-based arylsulfonamide, high-affinity, human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI), has been evaluated for anti-HIV activity in several in vitro assays. Preclinical assessment of brecanavir indicated that this compound potently inhibited HIV-1 in cell culture assays with 50% effective concentrations (EC50s) of 0.2 to 0.53 nM and was equally active against HIV strains utilizing either the CXCR4 or CCR5 coreceptor, as was found with other PIs. The presence of up to 40% human serum decreased the anti-HIV-1 activity of brecanavir by 5.2-fold, but under these conditions the compound retained single-digit nanomolar EC50s. When brecanavir was tested in combination with nucleoside reverse transcriptase inhibitors, the antiviral activity of brecanavir was synergistic with the effects of stavudine and additive to the effects of zidovudine, tenofovir, dideoxycytidine, didanosine, adefovir, abacavir, lamivudine, and emtricitabine. Brecanavir was synergistic with the nonnucleoside reverse transcriptase inhibitor nevirapine or delavirdine and was additive to the effects of efavirenz. In combination with other PIs, brecanavir was additive to the activities of indinavir, lopinavir, nelfinavir, ritonavir, amprenavir, saquinavir, and atazanavir. Clinical HIV isolates from PI-experienced patients were evaluated for sensitivity to brecanavir and other PIs in a recombinant virus assay. Brecanavir had a <5-fold increase in EC50s against 80% of patient isolates tested and had a greater mean in vitro potency than amprenavir, indinavir, lopinavir, atazanavir, tipranavir, and darunavir. Brecanavir is by a substantial margin the most potent and broadly active antiviral agent among the PIs tested in vitro.

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Betulinic Acid Derivatives That Target gp120 and Inhibit Multiple Genetic Subtypes of Human Immunodeficiency Virus Type 1

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00737-07 ◽

2007 ◽

Vol 52 (1) ◽

pp. 128-136 ◽

Cited By ~ 27

Author(s):

Weihong Lai ◽

Li Huang ◽

Phong Ho ◽

Zhijun Li ◽

David Montefiori ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Broad Spectrum ◽

Betulinic Acid ◽

V3 Loop ◽

Entry Inhibitors ◽

Immunodeficiency Virus ◽

Anti Hiv ◽

Hiv 1

ABSTRACT Betulinic acid (BA) derivatives can inhibit human immunodeficiency virus type 1 (HIV-1) entry or maturation depending on side chain modifications. While BA derivatives with antimaturation activity have attracted considerable interest, the anti-HIV-1 profile and molecular mechanism of BA derivatives with anti-HIV-1 entry activity (termed BA entry inhibitors) have not been well defined. In this study, we have found that two BA entry inhibitors, IC9564 and A43D, exhibited a broad spectrum of anti-HIV-1 activity. Both compounds inhibited multiple strains of HIV-1 from clades A, B, and C at submicromolar concentrations. Clade C viruses were more sensitive to the compounds than clade A and B viruses. Interestingly, IC9564 at subinhibitory concentrations could alter the antifusion activities of other entry inhibitors. IC9564 was especially potent in increasing the sensitivity of HIV-1YU2 Env-mediated membrane fusion to the CCR5 inhibitor TAK-779. Results from this study suggest that the V3 loop of gp120 is a critical determinant for the anti-HIV-1 activity of IC9564. IC9564 escape viruses contained mutations near the tip of the V3 loop. Moreover, IC9564 could compete with the binding of V3 monoclonal antibodies 447-52D and 39F. IC9564 also competed with the binding of gp120/CD4 complexes to chemokine receptors. In summary, these results suggest that BA entry inhibitors can potently inhibit a broad spectrum of primary HIV-1 isolates by targeting the V3 loop of gp120.

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Enhancement of human immunodeficiency virus type 1 infection by antisera to peptides from the envelope glycoproteins gp120/gp41.

Journal of Experimental Medicine ◽

10.1084/jem.174.6.1557 ◽

1991 ◽

Vol 174 (6) ◽

pp. 1557-1563 ◽

Cited By ~ 62

Author(s):

S B Jiang ◽

K Lin ◽

A R Neurath

Keyword(s):

Human Immunodeficiency Virus ◽

Human Immunodeficiency Virus Type ◽

Virus Type ◽

Neutralizing Antibodies ◽

Rational Design ◽

Envelope Glycoproteins ◽

V3 Loop ◽

Immunodeficiency Virus ◽

Hiv 1

Human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins (gp120 and gp41) elicit virus-neutralizing antibodies (VNAB) and also antibodies enhancing HIV-1 infection (EAB). Several epitopes eliciting VNAB have been defined, the principal virus-neutralizing determinant being assigned to the V3 loop of gp120. To provide a background for a rational design of anti-HIV vaccines, it also appears important to define domains eliciting EAB. This was accomplished by screening antisera against synthetic peptides covering almost the entire sequence of gp120/gp41 for their enhancing effects on HIV-1 infection of MT-2 cells, a continuous T cell line. Many (16/30) of the antisera significantly enhanced HIV-1 in the presence of human complement. Antibodies to complement receptor type 2 (CR2) abrogated the antibody-mediated enhancement of HIV-1 infection. Antisera to V3 hypervariable loops of 21 distinct HIV-1 isolates were also tested for their enhancing effects on HIV-1IIIB infection. 11 of these sera contained VNAB and 10 enhanced HIV-1IIIB infection. All antisera with virus-enhancing activity contained antibodies crossreactive with the V3 loop of HIV-1IIIB, and the virus-enhancing activity increased with increasing serological crossreactivity. These results suggest that immunization with antigens encompassing V3 loops may elicit EAB rather than protective antibodies if epitopes on the immunogen and the predominant HIV-1 isolate infecting a population are insufficiently matched, i.e., crossreactive serologically but not at the level of virus neutralization.

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