Highly enriched T-TILs expanded in the presence of CD40-FL and exogenous IL-2 exhibit cytotoxicity against autologous lymphoma cells. (A) T-TILs from patient FL4 were stimulated with CD40-FL cells (▪) or CD40-FL cells in the presence of 100 IU/mL IL-2 (•). The total number of viable cells was assessed by trypan blue exclusion test and the number of CD3⁺ T cells by immunophenotyping on day 0, 7, 14, 21, and 28 of culture. Viable cells were greater than 97% CD3⁺ T cells as assessed by phenotypic analysis. Cytotoxicity as examined by (B) chromium release assay or (C) JAM test of TCL cells after three stimulations with CD40-FL with addition of IL-2 at day 3 of coculture. Cytotoxicity was assessed on day 28 of culture. As targets, autologous CD40-FL cells (•), FL cells (▪), autologous CD40-B cells (□), allogeneic CD40-B cells (⋄), and allogeneic CD40-FL cells (○) were used in (B) and (C). Similar results were obtained using cells from patient FL6. (D) TCLs derived from T-TILs depleted of CD8⁺ T cells exhibit reduced cytotoxicity against FL and CD40-FL cells. (E) Blockade of MHC class I (⋄) and MHC class II (□) by MoAbs decreases anti-FL–directed T-cell cytotoxicity and the combination of both (○) almost abrogates cytotoxicity of autologous TCL to FL4.