J Virol. 2014 Nov; 88(21):12623-43.

PubMed ID: 25142591

Impact of clade, geography, and age of the epidemic on HIV-1 neutralization by antibodies

Hraber P, Korber BT, Lapedes AS, Bailer RT, Seaman MS, Gao H, Greene KM, McCutchan F, Williamson C, Kim JH, Tovanabutra S, Hahn BH, Swanstrom R, Thomson MM, Gao F, Harris L, Giorgi E, Hengartner N, Bhattacharya T, Mascola JR, Montefiori DC

Neutralizing antibodies (nAbs) are a high priority for vaccines that aim to prevent the acquisition of HIV-1 infection. Vaccine effectiveness will depend on the extent to which induced antibodies neutralize the global diversity of circulating HIV-1 variants. Using large panels of genetically and geographically diverse HIV-1 Env-pseudotyped viruses and chronic infection plasma samples, we unambiguously show that cross-clade nAb responses are commonly induced in response to infection by any virus clade. Nonetheless, neutralization was significantly greater when the plasma clade matched the clade of the virus being tested. This within-clade advantage was diminished in older, more-diverse epidemics in southern Africa, the United States, and Europe compared to more recent epidemics in Asia. It was most pronounced for circulating recombinant form (CRF) 07_BC, which is common in China and is the least-divergent lineage studied; this was followed by the slightly more diverse Asian CRF01_AE. We found no evidence that transmitted/founder viruses are generally more susceptible to neutralization and are therefore easier targets for vaccination than chronic viruses. Features of the gp120 V1V2 loop, in particular, length, net charge, and number of N-linked glycans, were associated with Env susceptibility and plasma neutralization potency in a manner consistent with neutralization escape being a force that drives viral diversification and plasma neutralization breadth. The overall susceptibility of Envs and potencies of plasma samples were highly predictive of the neutralization outcome of any single virus-plasma combination. These findings highlight important considerations for the design and testing of candidate HIV-1 vaccines that aim to elicit effective nAbs.