Ex vivo generation and expansion of anti‐tumor cytotoxic T‐cell lines derived from patients or their HLA‐identical sibling

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Abstract
Successful ex‐vivo priming and long‐term maintenance of anti‐tumor cytotoxic T‐cell (CTL) lines are preliminary conditions for their use in approaches of adoptive immunotherapy for patients with cancer. We describe the results of a novel procedure for generating in vitro anti‐tumor CTL using CD8‐enriched peripheral blood mononuclear cells (PBMC) and dendritic cells (DC), pulsed with irradiated tumor cells (TC) as source of tumor antigen. Eight patients were enrolled in our study: 4 sarcoma, 2 renal cell carcinoma, 1 ovarian carcinoma and 1 breast carcinoma. Ten anti‐tumor CTL‐lines cytotoxic towards patient TC were generated. Five CTL‐lines were obtained using both DC and PBMC from the patients (autologous setting). For 5 CTL‐lines, DC derived from an HLA‐identical sibling were employed (allogeneic setting): patients or siblings PBMC were used to generate CTL‐lines in 2 and 3 cases, respectively,. After tumor‐specific rounds of stimulation, followed by antigen‐independent cycle of expansion, CTL‐lines obtained in both autologous and allogeneic setting showed an expansion of the absolute number of cultured cells. In 6 of 10 CTL‐lines, the majority of effector cells (>70%) were CD3+/CD8+, while in the remaining 4, 40–70% of effector cells were CD3+/CD4+. Both CD8+ and CD4+ T cells displayed anti‐tumor cytotoxic activity. Spectratyping analysis of the TCR‐Vβ subfamilies revealed a preferential expansion of oligoclonal populations in 18 of 24Vβ subfamily. Altogether these results demonstrate that our experimental approach is suitable for efficiently generating and expanding anti‐solid tumor CTL to be used for adoptive immunotherapy.