Cytotoxicity of CTLs against primary tumor cells.

(A) Cytotoxicity of CTL lines generated from patients 1 (●) and 2 (○) against the autologous primary myeloma plasma cells at different E:T ratios. (B) Comparison of cytotoxicity of CTL lines generated from patients 1 (▪) and 2 (■) against the autologous primary myeloma plasma cells (Auto-PC) or the allogeneic myeloma plasma cells from the other patient (Allo-PC), or K562. E:T ratio was 20:1. (C) Inhibition by antibodies against MHC class I and class II or an isotypic control IgG on the cytotoxicity of CTLs from patients 1 (▪) and 2 (■). Data are expressed as the mean ± SEM of 3 independent experiments. Cold target inhibition assay using CTLs from patient 2 at an E:T ratio of 20:1, showing that (D) preincubation of CTLs with autologous Id-pulsed DCs (Auto-Id-DC) inhibited killing of labeled autologous primary cells (Auto-PC) and (E) preincubating with autologous primary cells inhibited the killing of labeled DCs pulsed with autologous Id proteins. Data are expressed as the mean ± SEM of 2 independent experiments.