Background: Cytokine-induced killer (CIK) cells are a heterogeneous population of immune cells derived from peripheral blood lymphocytes with a high proliferative potential ex vivo. This study shows a rapid and reproducible protocol for adoptive immunotherapy with CIK cells in patients with hematologic malignancies. For this purpose a new automatic cell processing device (CytoMate, Baxter Oncology) was tested to improve extensive manipulations of these cells.
Study design and methods: Twenty CIK expansions obtained from healthy donors and patients with hematologic malignancies were washed and refilled with fresh medium during culture with the CytoMate. Recovery, viability, and cytotoxic activity were evaluated. Six cryopreserved CIK procedures were thawed and processed for washing out dimethyl sulfoxide automatically. Recovery of cells, viability, and early apoptosis were measured immediately after washing, and cytotoxic activity against target cell lines K562 and Daudi was tested after short culture.
Results: Prewash volume of CIK cultures was 3600 mL (range, 1970-6000 mL). After automatic wash, the total CIK cell recovery was 85.3 percent (range, 78.5%-97.5%), and living cells were greater than 95 percent. After thawing, the median recoveries of total nucleated cells and natural killer T (NKT) cells were, respectively, 80.7 percent (range, 65%-95.5%) and 90.5 percent (range, 70.5%-98.5%). Thawed cells preserved their cytotoxic activity after cryopreservation (approx. 50% lysis at effector:target ratio of 40:1).
Conclusion: The automatic wash with the CytoMate showed a good recovery of viable CIK cells during expansion and allowed an efficient manipulation of thawed cells. The use of this simple and efficient washing technique is suitable for clinical-grade processing in cellular therapy protocols.