Engineered CD20-specific primary human cytotoxic T lymphocytes for targeting B-cell malignancy

Background Immunotherapy for B-cell lymphomas has evolved significantly with the advent of CD20-targeted Ab-based therapeutics. Strategies to invoke or augment cellular anti-lymphoma immune responses may also have considerable therapeutic potential and serve to further augment the clinical efficacy of MAbs. Methods We report here the acquisition by primary human cytotoxic T lymphocyte (CTL) effectors of re-directed CD20 specificity by their genetic modification to express a chimeric immunoreceptor consisting of an anti-CD20 single chain Ab extracellular domain molecularly fused to the T-cell receptor complex CD3-zeta cytoplasmic tail (scFvFc:zeta). Peripheral blood-derived human T-cells were transduced with naked DNA plasmid vector by electroporation then selected for G418 resistance. Results Following cloning in limiting dilution and ex vivo expansion to large numbers, scFvFc:zeta(+) TCRalpha/beta(+) CD4(-) CD8(+) CTL display redirected HLA-unrestricted CD20-specific lymphoma cell cytolysis proportional to the cell-surface density of the chimeric immunoreceptor. Engineered CTL clones are also activated through the chimeric immunoreceptor to produce T-c1 cytokines (IFN-gamma) upon co-culture with CD20(+) lymphoma stimulator cells. Additionally, CD20-specific CTL proliferate in the presence of lymphoma stimulators and IL-2 (5 U/mL). Discussion These studies provide the rationale for exploring the clinical utility of adoptive therapy with CD20-specific CTL as a component of immunotherapeutic targeting of CD20(+) malignancy.