Neutralization of multiple HIV-1 isolates from a single subject by autologous sequential sera

Titers of neutralizing antibodies to different strains of human immunodeficiency virus type 1 (HIV-1), including five isolates sequentially obtained from one infected subject, were determined using sequential serum samples obtained from that individual. Neutralizing antibodies were detected against the HIV-IIIB laboratory strain of HIV-1 and against a clinical isolate from another HIV-1-infected individual. Sera from the subject under investigation possessed differential ability to enact viral neutralization, depending on which homotypic clinical isolate was used. In general, it appeared that effective neutralization capacity was present in serum against homotypic viral isolates of HIV-1 only if these isolates were obtained at or before serum collection. These data suggest that variants of HIV-1 in infected individuals may not be effectively neutralized by antibodies that have been generated in these same people against previously dominant viral strains.