OBJECTIVETo observe if VIR576, an 20-mer peptide derived from the C-proximal subfragment of a1-antitrypsin (a1-AT) which inhibits human immunodeficiency virus type 1 (HIV-1) entry into the target cells by interacting with fusion peptide (FP), can also directly inhibit CD4(+) T cell activation in vitro.

METHODSSplenocytes isolated from DO11.10 OVA Tg mice were stimulated with ovalbumin or concanavalin A to test the effects of VIR576 on antigen-specific or non-antigen-specific T cell activation. Both primary CD4(+)CD25(-) T cells from DO11.10 mice and CD4(+) T cell line A2b were activated with specific antigens to evaluate the effects of VIR576.

RESULTSVIR576 inhibited antigen-specific splenocyte activation but had no significant effect on non-antigen-specific T-cell activation, which bypassed the crosstalk between the CD3-signaling complex and TCR. We furthermore observed that VIR576 could also down-regulate antigen-specific CD4(+) T-cell activation.

CONCLUSIONSGiven the high susceptibility of activated CD4(+) T cells in the mucosa to HIV-1 infection, the inhibitory effects of VIR576 on both HIV entry into the target cells and CD4(+) T-cell activation suggest the potential of VIR576 as a microbicide for prevention of sexual transmission of HIV.

Animals ; CD3 Complex ; CD4-Positive T-Lymphocytes ; drug effects ; HIV Fusion Inhibitors ; pharmacology ; HIV-1 ; Lymphocyte Activation ; drug effects ; Mice ; Mice, Transgenic ; Ovalbumin ; Peptide Fragments ; pharmacology ; alpha 1-Antitrypsin ; pharmacology

OBJECTIVETo screen the HIV-1 entry inhibitors targeting HIV-1 gp120 from the IBS natural product database by virtual screening based on the binding mode of the neutralizing antibody VRC01 with HIV-1 gp120 and investigate the anti-viral activities of the inhibitors and their action mechanisms.

METHODSThe binding interaction of the candidate molecules binding gp120 and changes of the binding free energy were analyzed by MM-PBSA calculation. The anti-HIV-1 activities of the tested compounds were detected by HIV-1 pseudotyped virus, laboratory-adapted HIV-1 and a cell-cell fusion assay. The cytotoxicity of the studied molecules was examined by XTT colorimetric assay. The mechanisms of the anti-viral activities of the candidate molecules were analyzed using enzyme-linked immunosorbent assay.

RESULTSA total of 19 molecules with distinct reduction of the binding free energy after binding with gp120 were screened from 40000 molecules. Among them, NC-2 showed anti-HIV-1 activities against HIV-1 pseudotyped virus and laboratory-adapted HIV-1, and was capable of blocking HIV-1 envelope-mediated cell-cell fusion. The IC50 of NC-2 for inhibiting HIV-1IIIB and pseudotyped HIV-1JRFL infection were 1.95∓0.44 µmol/L and 10.58∓0.13 µmol/L, respectively. The results of ELISA suggested that NC-2 could inhibit the binding of HIV-1 gp120 to CD4 without blocking the formation of gp41 six-helix bundle in vitro.

CONCLUSIONThis computer-based virtual screening method can be used to screen HIV-1 entry inhibitors targeting gp120. Using this virtual screening approach combined with anti-viral activity screening, we obtained a potent HIV-1 entry inhibitor NC-2 with novel structure.

Anti-HIV Agents ; pharmacology ; Antibodies, Monoclonal ; pharmacology ; Antibodies, Neutralizing ; pharmacology ; Binding Sites ; Cell Fusion ; Cell Line ; Drug Discovery ; Drug Evaluation, Preclinical ; HIV Antibodies ; pharmacology ; HIV Envelope Protein gp120 ; antagonists & inhibitors ; HIV-1 ; drug effects ; Humans ; Microbial Sensitivity Tests

Human immunodeficiency virus (HIV) infects the host cells by the fusion of viral and cell membranes. Blocking the combining between HIV and the receptors can prevent HIV from entering the host cells. We designed an invasion-inhibitor for HIV-1 targeting dendritic cell (DC), including 2 important HIV-1 receptors CD4 and CCR5, and 2 molecules Flt3-L and Mip-3alpha. With the synthetic gene of the inhibitor, 2 eukaryotic expression vectors pABK-CKR5-CD4/Flt3L-Mip3alpha (pABK-HIV-MF) and pABK-CKR5-CD4 (pABK-HIV-MT) were constructed and transfected into HEK 293 cells for expression. Results from RT-PCR, immunofluorescent assay, ELISA and Western blot approved that the invasion-inhibitor for HIV-1 was successfully and exactly expressed in the eukaryotic cells. Current study formed a solid base for the further research on the function of inhibitors for HIV-1 and elimination targeting DC.
Artificial Gene Fusion ; CD4 Antigens ; biosynthesis ; genetics ; Chemokine CCL20 ; biosynthesis ; genetics ; Dendritic Cells ; immunology ; metabolism ; Genetic Vectors ; genetics ; HEK293 Cells ; HIV Envelope Protein gp120 ; genetics ; HIV-1 ; physiology ; Humans ; Receptors, CCR5 ; biosynthesis ; genetics ; Receptors, HIV ; antagonists & inhibitors ; Transfection ; fms-Like Tyrosine Kinase 3 ; biosynthesis ; genetics

In the two decades since AZT was first approved for clinical use in 1987, 24 additional antiretroviral agents have been approved. They include 7 nucleoside analogs, a nucleotide analog and 4 non-nucleoside reverse transcriptase inhibitors, 10 protease inhibitors, 2 entry inhibitors and an integrase inhibitor. More than 20 investigational agents are currently being studied in clinical trials. Highly active antiretroviral therapy (HAART), which involves a combination of anti-HIV-1 drugs, is extremely effective in suppressing HIV-1 replication and increasing CD4+ number and results in substantial reductions in HIV-1-related morbidity and mortality. In last 20 years, much has been learned about resistance to antiretroviral drugs, drug interactions and metabolic complications of antiviral drug use. Drugs are now selected on the basis of resistance tests and on the risk of specific drug complications in individual patients. As a result, decisions about the therapy of HIV/AIDS have become personalized and are made on a patient-by-patient basis. With appropriate medical management, a person with HIV-1 now has the possibility of a nearly normal life expectancy.
Anti-HIV Agents ; adverse effects ; pharmacology ; therapeutic use ; Antiretroviral Therapy, Highly Active ; Cyclohexanes ; chemistry ; pharmacology ; therapeutic use ; Drug Resistance, Viral ; HIV Envelope Protein gp41 ; chemistry ; therapeutic use ; HIV Fusion Inhibitors ; chemistry ; pharmacology ; therapeutic use ; HIV Infections ; drug therapy ; HIV Integrase Inhibitors ; chemistry ; pharmacology ; therapeutic use ; HIV Protease Inhibitors ; chemistry ; pharmacology ; therapeutic use ; HIV Reverse Transcriptase ; chemistry ; pharmacology ; therapeutic use ; HIV-1 ; drug effects ; physiology ; Humans ; Molecular Structure ; Peptide Fragments ; chemistry ; therapeutic use ; Pyrrolidinones ; chemistry ; pharmacology ; therapeutic use ; Raltegravir Potassium ; Saquinavir ; chemistry ; pharmacology ; therapeutic use ; Triazoles ; chemistry ; pharmacology ; therapeutic use ; Virus Replication ; drug effects ; Zidovudine ; chemistry ; pharmacology ; therapeutic use

HIV-1 fusion inhibitors are a new class of anti-HIV compounds, which block the entry of HIV into target cells through preventing the fusion between viral and cell plasma membrane and thus interrupt the initial steps of viral replication. T-20 (enfuvirtide), which has been clinically approved as the first fusion inhibitor of HIV-1 by U.S. FDA in 2003, can suppress replication of HIV variants with multi-drug resistance to reverse transcriptase and protease inhibitors. Peptides and small molecules display potent anti-HIV fusion activities by targeting gp41 thus inhibit its fusogenic function. In recent years, with the development of studies on the molecular mechanism of HIV membrane fusion process and the function of gp41, many new fusion inhibitors are found and some have been in advanced clinical trials. This review discusses recent progress in the development of HIV-1 fusion inhibitors targeting the gp41.
Anti-HIV Agents ; chemical synthesis ; chemistry ; pharmacology ; Drug Resistance, Multiple ; HIV Envelope Protein gp41 ; chemical synthesis ; chemistry ; pharmacology ; HIV Fusion Inhibitors ; chemical synthesis ; chemistry ; pharmacology ; HIV Infections ; drug therapy ; HIV-1 ; drug effects ; physiology ; Humans ; Peptide Fragments ; chemical synthesis ; chemistry ; pharmacology ; Peptides ; chemical synthesis ; chemistry ; pharmacology ; Recombinant Fusion Proteins ; chemical synthesis ; chemistry ; pharmacology ; Virus Replication ; drug effects ; alpha 1-Antitrypsin ; chemical synthesis ; chemistry ; pharmacology

HIV and AIDS remain as the crucial global health concern, therefore, research and development of novel anti-HIV-1 chemical therapeutics is still of paramount significance, which may be illuminated by cases of successful marketed drugs. Herein, we document the discovery and biological profile of new anti-HIV-1 drugs approved by FDA between 2005 and 2008 and some drug candidates are also discussed.
Acquired Immunodeficiency Syndrome ; drug therapy ; Anti-HIV Agents ; chemistry ; pharmacology ; therapeutic use ; HIV Fusion Inhibitors ; chemistry ; pharmacology ; therapeutic use ; HIV Infections ; drug therapy ; HIV Integrase Inhibitors ; chemistry ; pharmacology ; therapeutic use ; HIV Protease Inhibitors ; chemistry ; pharmacology ; therapeutic use ; HIV-1 ; drug effects ; Humans ; Molecular Structure ; Reverse Transcriptase Inhibitors ; chemistry ; pharmacology ; therapeutic use

Human immunodeficiency virus type 1 (HIV-1) is the causative agent of acquired immunodeficiency disease syndrome (AIDS). After over 26 years of efforts, there is still not a therapeutic cure or an effective vaccine against HIV/AIDS. The clinical management of HIV-1 infected people largely relies on antiretroviral therapy (ART). Although highly active antiretroviral therapy (HAART) has provided an effective way to treat AIDS patients, the huge burden of ART in developing countries, together with the increasing incidence of drug resistant viruses among treated people, calls for continuous efforts for the development of anti-HIV-1 drugs. Currently, four classes of over 30 licensed antiretrovirals (ARVs) and combination regimens of these ARVs are in use clinically including: reverse transcriptase inhibitors (RTIs) (e.g. nucleoside reverse transcriptase inhibitors, NRTIs; and non-nucleoside reverse transcriptase inhibitors, NNRTIs), protease inhibitors (PIs), integrase inhibitors and entry inhibitors (e.g. fusion inhibitors and CCR5 antagonists). Here, we intend to provide updated information of currently available antiretroviral drugs for ART to promote the development of novel anti-HIV-1 drugs.
Acquired Immunodeficiency Syndrome ; drug therapy ; Anti-HIV Agents ; chemistry ; pharmacology ; therapeutic use ; HIV Fusion Inhibitors ; chemistry ; pharmacology ; therapeutic use ; HIV Infections ; drug therapy ; HIV Integrase Inhibitors ; chemistry ; pharmacology ; therapeutic use ; HIV Protease Inhibitors ; chemistry ; pharmacology ; therapeutic use ; HIV-1 ; drug effects ; Humans ; Molecular Structure ; Reverse Transcriptase Inhibitors ; chemistry ; pharmacology ; therapeutic use

This review discusses recent progress in the development of anti-HIV agents, with emphasis on small molecule HIV-1 entry inhibitors. The entry inhibitors primarily target HIV-1 envelope glycoproteins or the cellular receptors, CD4 and chemokine receptors. Two of the entry inhibitors, enfuvirtide and maraviroc, have been approved by the US FDA for AIDS therapy. The drug resistance associated with some of the entry inhibitors will also be discussed.
Anti-HIV Agents ; chemistry ; pharmacology ; therapeutic use ; CCR5 Receptor Antagonists ; CD4 Antigens ; drug effects ; Cyclohexanes ; pharmacology ; therapeutic use ; Drug Resistance, Viral ; HIV Envelope Protein gp120 ; pharmacology ; HIV Envelope Protein gp41 ; pharmacology ; therapeutic use ; HIV Fusion Inhibitors ; chemistry ; pharmacology ; therapeutic use ; HIV Infections ; drug therapy ; HIV-1 ; drug effects ; Humans ; Molecular Structure ; Peptide Fragments ; pharmacology ; therapeutic use ; Receptors, CCR5 ; physiology ; Receptors, CXCR4 ; antagonists & inhibitors ; Receptors, Chemokine ; drug effects ; Triazoles ; pharmacology ; therapeutic use

OBJECTIVETo develop an objective bioassay for quantitative detection of HIV-induced cell-cell fusion for screening HIV entry inhibitors.

METHODSHL2/3 cells expressing HIV envelope proteins gp120/gp41, Tat, and other HIV proteins were co-cultured with HeLa-CD4-LTR-beta-gal cells expressing CD4 receptor and HIV LTR triggered reporter gene beta-galactosidase. The enzyme activities of beta-galactosidase were detected by a chromogenic substrate, chlorophenol red-beta-galactopyranoside (CPRG). Specific HIV entry inhibitors were used to validate the established detecting method.

RESULTSNo syncytium was formed by mixing HL2/3 and HeLa-CD4-LTR-beta-gal cells. However, the membrane could be fused and the Tat expressed by HL2/3 cells could bind to HIV LTR on HeLa-CD4-LTR-beta-gal cells and trigger the expression of beta-galactosidase. CPRG allowed quantitative and sensitive detection of the activity of beta-galactosidase. Further studies showed that HIV entry inhibitors could inhibit the activity of beta-galactosidase in a dose-dependent manner.

CONCLUSIONWe have developed a simple, cheap, objective and quantitative non-infectious cell-cell fusion bioassay that can be used to screen for anti-HIV agents targeting the virus entry from natural and synthetic compound libraries.

Biological Assay ; Cell Fusion ; Cell Line ; Coculture Techniques ; Drug Evaluation, Preclinical ; methods ; HIV Envelope Protein gp120 ; metabolism ; HIV Envelope Protein gp41 ; metabolism ; HIV Fusion Inhibitors ; chemistry ; pharmacology ; Humans ; beta-Galactosidase ; metabolism

OBJECTIVETo observe the inhibitory effect of 1,2,6-Tri-O-galloyl-beta-D-glucopyranose (TGGP) from Balanophora japonica Makino on human immunodeficiency virus (HIV) entry into the host cells and explore the mechanisms.

METHODSTGGP was purified from Balanophora japonica Makino by n-hexane and ethyl acetate extraction and column chromatography. The inhibitory activity of TGGP on HIV gp41 six-helix bundle formation was measured with ELISA, N-PAGE and SE-HPLC, and the inhibitory effect of TGGP on HIV envelope grlycoprotein-induced cell-cell fusion was detected using a non-infectious cell-based assay.

RESULTSTGGP inhibited HIV gp41 six-helix bundle formation, with an IC50 of 1.37-/+0.19 microg/ml as determined by ELISA, and this activity was further confirmed by N-PAGE and SE-HPLC. TGGP at 25 microg/ml significantly inhibited syncytium formation between the effector (CHO-WT) and the target (MT-2) cells.

CONCLUSIONThe HIV transmembrane subunit gp41 mediates the entry of HIV into the target cells. TGGP can inhibit HIV fusion and entry into the target cells by inhibiting the formation of gp41 six-helix bundles, suggesting the potential of TGGP as a microbicide to prevent sexual transmission of HIV.

Anti-HIV Agents ; pharmacology ; Cell Membrane ; drug effects ; metabolism ; HIV Envelope Protein gp41 ; metabolism ; HIV Fusion Inhibitors ; pharmacology ; HIV-1 ; drug effects ; growth & development ; metabolism ; Humans ; Hydrolyzable Tannins ; pharmacology ; Membrane Fusion ; drug effects