PRIME-XV T Cell CDM is an animal component–free medium for T-cell culture. The medium has been developed to maximize consistent growth of T cells while maintaining their functionality and therapeutic potential. An important trend in cell-culture media for gene therapies and immunotherapies is the move away from animal-derived and undefined components to serum-free, animal component–free, and chemically defined culture conditions. When working with T cells, the advantage of this is twofold: Animal-derived components are variable between lots, and the naturally occurring cytokines and growth factors in them can result in undesirable effects. For example, cytokines and growth factors have been shown to impact growth, phenotype, and the potential of T cells to polarize into therapeutic subtypes. PRIME-XV T Cell CDM removes this variability to provide more consistency between lots. Chemically defined media (CDM) also reduce the risk of introducing foreign agents or impurities from undefined components, thereby facilitating scale-up to commercial production and the regulatory submission process.