An Adoptive Immunotherapy Approach For Colorectal Cancer (Crc) Patients

3074 Background: Adoptive T-cell transfer (ACT) refers to an immunotherapeutic approach in which anti-tumor T lymphocytes are identified, grown ex vivo and re-infused into the cancer patients. This strategy was successfully applied in metastatic melanoma and renal cell carcinoma. However, adoptive immunotherapy do not play an important role in the treatment of advanced CRC. We developed an ACT protocol for CRC using as source of tumor antigens the irradiated primary CRC cell lines, captured by dendritic cells (DC) to stimulate in vitro a specific autologus activation of patient’s T cytotoxic lymphocytes (CTL) against tumor. Methods: 78 CRC patients were enrolled. Tumor tissues were obtained at surgery, together with 100 ml of heparinized peripheral blood. Tumors were mechanically dissociated to a single-cell suspension and cultured to obtain a primary cell line from each patient. DCs were generated from monocytes, cultured with recombinant human Interleukin-4 and recombinant human Granulocyte- Macrophage Colony-Stimulating Factor for 6-7 days. Anti-tumor CTLs were elicited in co/micro-cultures using DCs, autologous apoptotic tumor cells and T CD8+ lymphocytes enriched effectors, in presence of weakly irradiated T CD4+ lymphocytes, Interleukin 7 and Interleukin 12, with weekly stimulation. CTLs Interferon-γ (IFN-γ) secretion was assessed by ELISpot assay. Results: Primary tumor cell lines were obtained from 20 out of 78 patients, with a success rate of 25,6%. DCs were generated from 26 patients, and 6 had the corresponding primary tumor cell line. Co/micro-cultures were set up for 6 patients. ELISpot results showed a strong and significant IFN-γ secretion at the third, fourth and fifth stimulations for one patient and at the second for another patient, whereas for three patients a weak secretion was detected during the second and third stimulations. Conclusions: The percentage of success in the establishment of primary colon cell lines was higher than those reported in literature, although the intestinal flora adversely affected their obtainment. The generation of tumor-specific CTLs could be useful for supporting an ACT approach in CRC.