Cytotoxicity of PBMC of patient 2 against idiotype-expressing autologous LCL after stimulation with idiotype-presenting autologous DC.

CD8⁺ PBMC of patient 2 were stimulated repetitively with autologous DC loaded or transduced with idiotype derived from the patient's lymphoma cells. Cytotoxic activity was assessed in a standard ⁵¹Cr release assay with idiotype-expressing autologous LCL or the NK target cell line K562. An excess of unlabeled K562 cells was added to LCL target cells to inhibit NK activity. □: DC loaded with recombinant Fab fragment derived from the patient's lymphoma; ▵ and ▿: DC transduced with SFV vectors encoding autologous lymphoma-derived immunoglobulin heavy or light chain; LCL/Fd1, LCL/IgL1, LCL of patient 2 stably transfected with vectors encoding the idiotype heavy or light chain of the lymphoma of patient 1; LCL/Fd2, LCL/IgL2, LCL of patient 2 stably transfected with vectors encoding the idiotype heavy or light chain of the lymphoma of patient 2.