HIV Life Cycle
CD4, a member of the IgG superfamily, is a cell surface receptor expressed on helper T lymphocytes, monocytes, B-lymphocytes and several other cells. In addition to being a receptor for HIV, CD4 participates in the recognition of foreign peptides bound to class II MHC complexes1.
The virion surface envelope glycoprotein, gp120, consist of five variable domains (V1-V5) and five conserved domains (C1-C5). The high-affinity binding of CD4 to gp120 is believed to involve interactions between the C3 and C4 domains of gp120 and the N-terminal extracellular domain of CD42.
This article was provided by U.S. National Institute of Allergy and Infectious Diseases.