Titers of HIV-specific neutralizing antibodies. (A) Neutralizing activity of plasma from viremic patients, ES, and patient 169 against recombinant virus with Env from the laboratory strain SF162. The open symbols denote titers that were greater than 1:4. (B) Neutralizing activity of plasma from Patient 169 against recombinant virus with Env from 1999 and 2010-1A isolates. Relative infection of TZMb1 cells by the recombinant isolates is shown in the presence of four fold dilutions of plasma.