Primary virus envelope cross-reactivity of the broadening neutralizing antibody response during early chronic human immunodeficiency virus type 1 infection

To test the hypothesis that changing neutralizing antibody responses agains t human immunodeficiency virus type 1 (HIV-1) during chronic infection were a response to emergence of neutralization escape mutants, we cloned expres sed and characterized envelope clones from patients in the Multicenter AIDS Cohort Study (MACS). Pseudotyped HIV-1 envelope clones obtained from diffe ring time points were assessed for sensitivity to neutralization by using s era from different times from the same and different patients. Clones from early and late time points during chronic infection had similar neutralizat ion sensitivity, and neutralizing antibody responses cross-reacted with ear ly, late, and heterologous envelopes. The potential for broadly effective H IV-1 immunization is supported.