P04-38. Crystal structure of gp120 in complex with the CD4-binding-site antibody b13 suggests precise targeting is needed for neutralization

Background The CD4-binding site (CD4BS) on HIV-1 gp120 is functionally conserved and structurally invariant, and the broadly neutralizing antibody b12 exploits this site of vulnerability to achieve neutralization. However, most antibodies that target this general epitope cannot effectively neutralize HIV-1. Why is HIV-1 resistant to neutralization by these antibodies? Comparison at the atomic level of gp120 binding to effective and non-effective antibodies may reveal the answer.