Issues concerning the large scale cryopreservation of peripheral blood mononuclear cells (PBMC) for immunotherapy trials

Immunotherapy of cancer is being developed as an alternative or adjuvant to conventional therapies such as: surgery, chemotherapy and/or radiation treatment. Immunotherapy laboratories routinely process and prepare for injection large numbers of anti-tumor effector cells. The process of cryopreservation is critical to the success of immunotherapy. Standardized safe procedures are required. In the current report, we show the ability to cryopreserve peripheral blood mononuclear cells (PBMC) in Plasmalyte-A, a fluid replacement medium approved by the FDA. These studies show that this medium can be used in place of human serum in terms of cell recovery, cell surface phenotype and response to PHA. However, T cell cytokine release stimulated through the CD3 receptor was altered following the cryopreservation process. These results are important toward the improvement of cryopreservation techniques for their use in immunotherapy.