Entry and fusion inhibitors of HIV

Pradimicin A, a carbohydrate-binding nonpeptidic lead compound for treatment of infections with viruses with highly glycosylated envelopes, such as human immunodeficiency virus

Pradimicin A (PRM-A), an antifungal nonpeptidic benzonaphtacenequinone antibiotic, is a low-molecular-weight (molecular weight, 838) carbohydrate binding agent (CBA) endowed with a selective inhibitory activity against human immunodeficiency virus (HIV). It invariably inhibits representative virus strains of a variety of HIV-1 clades with X4 and R5 tropisms at nontoxic concentrations. Time-of-addition studies revealed that PRM-A acts as a true virus entry inhibitor. PRM-A specifically interacts with HIV-1 gp120 and efficiently prevents virus transmission in cocultures of HUT-78/HIV-1 and Sup T1 cells. Upon prolonged exposure of HIV-1-infected CEM cell cultures, PRM-A drug pressure selects for mutant HIV-1 strains containing N-glycosylation site deletions in gp120 but not gp41. A relatively long exposure time to PRM-A is required before drug-resistant virus strains emerge. PRM-A has a high genetic barrier, since more than five N-glycosylation site deletions in gp120 are required to afford moderate drug resistance. Such mutated virus strains keep full sensitivity to the other known clinically used anti-HIV drugs. PRM-A represents the first prototype compound of a nonpeptidic CBA lead and, together with peptide-based lectins, belongs to a conceptually novel type of potential therapeutics for which drug pressure results in the selection of glycan deletions in the HIV gp120 envelope.

Polycyclic peptide and glycopeptide antibiotics and their derivatives as inhibitors of HIV entry

Antiviral activity and other biological properties of two groups of polycyclic peptides are discussed. Antibiotics of the complestatin–kistamycin group have a structural motif similar to that of the peptide core of antibacterial antibiotics of the vancomycin–teicoplanin group though no amino acid component in the chloropeptin–kistamicin antibiotics is identical to an amino acid incorporated in the peptide core of the antibiotics of the vancomycin–teicoplanin group. Chloropeptins and the hydrophobic several derivatives of antibacterial antibiotics are inhibitors of HIV and some other viruses. They interfere with the viral (i.e. HIV) entry process. Chemical modifications of natural glycopeptide antibiotics led to the compounds with antiviral properties whereas antibacterial properties were lost. These glycopeptide aglycons derivatives can be envisaged as potential lead compounds for application as microbicides against sexual HIV transmission.

In vitro development of resistance to human immunodeficiency virus protease inhibitor GW640385

Development of in vitro resistance to GW640385, a new human immunodeficiency virus type 1 protease inhibitor, was studied. Variants characterized included one with <4-fold resistance and amino acid substitutions Q58E/A71V (protease) and P452K (Gag) and one with >50-fold resistance and amino acid substitutions L10F/G16E/E21K/A28S/M46I/F53L/A71V (protease) and L449F/P453T (Gag). The A28S substitution substantially reduced replication capacity.