HHV6B multiantigen-specific CTLs kill HHV6B wild-type virus-infected targets. (A) Schematic of our multiantigen-specific HHV6 CTL generation process. (B) By IFN-γ ELISPOT, these multiantigen-specific lines were specific for the stimulating pepmixes. Results are expressed as SFCs/1 × 105 input cells. (C) IHC analysis of CD14-selected monocytes infected with the HHV6B wild-type virus strain Z29 or the mock-infected controls. The IHC pictures were taken using 10× magnification at an exposure of 6 ms on an Olympus BX41 microscope, and images were captured using Q-capture software (Q-imaging). Autologous monocytes alone, or pepmix-pulsed or HHV6 wild-type virus-infected cells, were used as targets in a standard 4-6 hour Cr51 release assay (D). Data are mean ± SEM (% specific lysis at an effector/target ratio of 40:1; n = 4). (E) Representative FACS results of a 24-hour coculture assay where either uninfected or HHV6 Z29-infected autologous monocytes (CD11c+) were cultured with nonspecific or HHV6 multiantigen-specific CTLs (CD3+). (F) Summary results from 4 donors where the percentage of residual monocytes after treatment, as quantified by FACS analysis, were plotted (mean ± SD).
