Figure 7. Unimpaired cytotoxicity and perforin secretion but severely suppressed proliferation and effector molecule secretion of retrovirally transduced CMV specific human CD8⁺ T cells.

Human primary CD8⁺ T cells retrovirally transduced with a TCR specific for the CMV peptide pp65_aa495–503 (▪) or mock transduced T cells (▴) were activated with K562-A2 cells pulsed with the cognate pp65_aa495–503 peptide (100 nM) in the presence (–––) or absence (- - -) of arginine at the indicated E:T ratios (incubation time 4 h). T cell mediated, antigen specific tumor cell cytotoxicity was assessed by [⁵¹Cr]-Chromium release assay (A). In parallel, identical T cell-K562-A2 co-cultivation assays were set up at an E:T ratio of 20∶1 for 48 h (B–E). Antigen specific T cell proliferation was assessed by [³H]thymidine incorporation for additional 16 h (B) while IFN-γ (C), granzyme B (D) and perforin (E) concentration were measured in the 48 h supernatant by ELISA. −Arg: no arginine; +Arg: 1000 µM arginine. Data in A–E are representative of 2 different experiments with a total of 4 different TCR constructs and 3 independent HD.