CD4-MODIFIED SYNTHETIC PEPTIDES CONTAINING PHENYLALANINE INHIBIT HIV-1 INFECTION IN-VITRO

Phenylalanine-containing peptides from CD4 were synthesized based on c hemical similarity with active CD4(81-92)-benzylated peptides. The syn thetic peptide FYIFFVEDQKEEDD blocked the binding of gp120 to CD4 and inhibited 50% human immunodeficiency virus (HIV)-induced syncytia form ation at a concentration (IC50) of similar to 40-50 mu M and HIV p17 e xpression with an IC50 of similar to 67 mu M. The peptide is not toxic to cells in vitro. Moreover, acute toxicity studies carried out in Sw iss mice showed the peptide to be nontoxic at a dose of 2,000 mg/kg. T his phenylalanine-substituted CD4 peptide may prove to be useful in th e treatment of AIDS.