Authors:
John Pietzsch, Johannes F. Scheid, Hugo Mouquet, Florian Klein, Michael S. Seaman, Mila Jankovic, Davide Corti, Antonio Lanzavecchia, and Michel C. Nussenzweig
Summary:
The identification and characterization of conserved epitopes on the HIV-1 viral spike that are immunogenic in humans and targeted by neutralizing antibodies is an important step in vaccine design. Antibody cloning experiments revealed that 32% of all HIV-neutralizing antibodies expressed by the memory B cells in patients with high titers of broadly neutralizing antibodies recognize one or more “core” epitopes that were not defined. Here, we show that anti-core antibodies recognize a single conserved epitope on the gp120 subunit. Amino acids D474, M475, R476, which are essential for anti-core antibody binding, form an immunodominant triad at the outer domain/inner domain junction of gp120. The mutation of these residues to alanine impairs viral fusion and fitness. Thus, the core epitope, a frequent target of anti–HIV-neutralizing antibodies, including the broadly neutralizing antibody HJ16, is conserved and indispensible for viral infectivity. We conclude that the core epitope should be considered as a target for vaccine design.
Source:
The Journal of Experimental Medicine; Vol. 207, No. 9, 1995-2002 (08/02/10)