Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
We have identified several patient sera showing potent and broad HIV-1 neutralization. Using antibody adsorption and elution from selected gp120 variants, the neutralizing specificities of the two most broadly reactive sera were mapped to the primary receptor CD4-binding region of HIV-1 gp120. Novel antibodies to the CD4-binding site are elicited in some HIV-1-infected individuals, and new approaches to present this conserved region of gp120 to the immune system may result in improved vaccine immunogens.