ABSTRACT

CD4 is a cell-surface glycoprotein that is found primarily on T lymphocytes. It belongs to the imm unoglobulin superfamily of molecules that generally serve in recognition processes, and may play a direct role in T-cell activation. H um an CD4 is also the receptor for the hum an immunodeficiency virus (HIV).1 The initial step in viral entry is high affinity binding of the HIV gpl20 glycoprotein to CD4 (KD ~ 10-9M), which then leads to fusion of viral and cell membranes. Inhibiting gpl20-CD4 binding and blocking viral attachm ent is thus a potentially valuable antiviral strategy in AIDS therapy.