Background Cell therapy is a promising strategy for the treatment of various diseases including degenerative disorders and cancer. This therapy takes advantage of immune cells’ capacity to attack cancer or the potential of stem cells to self-renew, differentiate into multiple cell lineages, and regulate the immune response. The expansion, differentiation, and cryopreservation of cells, for therapeutic purposes, prefers the use of GMP and chemically-defined serum-free solutions to ensure consistency and minimize immunogenic reactions, risk of pathogen contamination, and cytotoxicity. In this study, we developed two GMP serum-free cryopreservation solutions. A low DMSO solution designed to freeze T cells and a DMSO-free solution for Mesenchymal Stem Cells (MSCs).

Methods To test the performance of these solutions, human PBMC-derived T cells or human Mesenchymal Stem Cells were resuspended in each cryopreservation solution and stored at -80°C for a minimum of 24h. Then, the cells were transferred to liquid nitrogen for a minimum of 48h. Cell viability and percentage of cell recovery were tested at thaw. The reactivation capacity, in the case of T cells, and the phenotype, morphology, and differentiation potential of MSCs were evaluated post-thaw after multiple days in culture.

Results Our results show we were able to develop two GMP chemically-defined and serum-free formulations comparable or superior in performance to serum-containing freezing media or existing commercially available DMSO-free freezing solutions. These novel solutions were able to preserve the viability and the phenotypic characteristics of T cells and MSCs after thawing.

Conclusions Our development work allowed BioLegend to gain in-depth knowledge of the impact of serum and DMSO in cell biology to provide custom-tailored solutions. Thus, BioLegend continues to develop a much-needed end-to-end workflow solution for cell therapy to support the progression of research into clinical applications.