Immunity. 2018 Dec 18; 49(6):1162-1174.e8.

PubMed ID: 30552024

Inference of the HIV-1 VRC01 antibody lineage unmutated common ancestor reveals alternative pathways to overcome a key glycan barrier

Bonsignori M, Scott E, Wiehe K, Easterhoff D, Alam SM, Hwang KK, Cooper M, Xia SM, Zhang R, Montefiori DC, Henderson R, Nie X, Kelsoe G, Moody MA, Chen X, Joyce MG, Kwong PD, Connors M, Mascola JR, McGuire AT, Stamatatos L, Medina-Ramirez M, Sanders RW, Saunders KO, Kepler TB, Haynes BF

Elicitation of VRC01-class broadly neutralizing antibodies (bnAbs) is an appealing approach for a preventative HIV-1 vaccine. Despite extensive investigations, strategies to induce VRC01-class bnAbs and overcome the barrier posed by the envelope N276 glycan have not been successful. Here, we inferred a high-probability unmutated common ancestor (UCA) of the VRC01 lineage and reconstructed the stages of lineage maturation. Env immunogens designed on reverted VRC01-class bnAbs bound to VRC01 UCA with affinity sufficient to activate naive B cells. Early mutations defined maturation pathways toward limited or broad neutralization, suggesting that focusing the immune response is likely required to steer B cell maturation toward the development of neutralization breadth. Finally, VRC01 lineage bnAbs with long CDR H3s overcame the HIV-1 N276 glycan barrier without shortening their CDR L1, revealing a solution for broad neutralization in which the heavy chain, not CDR L1, is the determinant to accommodate the N276 glycan.