Enhancement of CD30-specific CTL cytotoxicity in XIAP down-regulated H-RS cells. Specificity of target cell lysis mediated by CD30-specific T cells. Isolated peripheral blood CD3⁺ T cells grafted by retroviral gene transfer with the CD30-specific HRS3scFv-Fc-zeta immunoreceptor and nontransduced T cells were incubated with CD30^- Colo320 (A) or CD30⁺ L540 (B) cells (each 5 × 10⁵ cells/well) for 24 hours. Viability of target cells was monitored by an XTT-based colorimetric assay. XIAP down-regulation improves antigen-specific CTL cytotoxicity against HL cells. Nontransduced and HRS3scFv-Fc-zeta receptor-grafted CD3⁺ T cells were incubated for 24 hours with L540-scr-shRNA or L540-XIAP-shRNA target cells (each 5 × 10⁵ cells/well). Viability of target cells was monitored by an XTT-based colorimetric assay. Data are mean ± SD values from 3 individual experiments performed in triplicate.