This product is MRC-5 serum-free medium, a chemically defined medium specifically designed for the in vitro culture of human embryonic lung diploid fibroblasts (MRC-5). Its core formulation precisely addresses the unique requirements of this cell line in viral vaccine production (e.g., varicella and rabies vaccines) and cellular senescence research. By optimizing key amino acids, vitamins, and specific growth factor combinations, it maintains normal diploid karyotypes and physiological functions while ensuring efficient viral amplification and reproducible experimental data. This formulation completely eliminates batch-to-batch variability and exogenous factor risks associated with serum introduction.