Plan your MCB and WCB vial requirements, QC allocation, stability testing schedule, and product lifecycle cell banking needs. Compliant with ICH Q5D guidance.
Estimate total WCB and MCB vial requirements across the entire product development lifecycle.
Standard freeze and thaw protocols for mammalian cell banking. Adapt timings and volumes to your specific cell line and SOP.
A Master Cell Bank (MCB) is the primary cryopreserved stock derived from the original cell clone, manufactured under GMP conditions and fully characterized. A Working Cell Bank (WCB) is derived from one or more vials of the MCB by expansion and cryopreservation. WCBs are used for routine production campaigns, protecting the limited MCB supply.
An MCB typically contains 200-500 vials, enough to derive all WCBs needed over the entire product lifecycle (clinical through commercial), plus vials for QC testing, stability studies, regulatory retention, and a safety margin of 10-20%.
ICH Q5D requires identity testing, sterility, mycoplasma testing, adventitious virus testing (in vitro and in vivo), species-specific virus testing (e.g., retrovirus for CHO), karyology, and viability post-thaw. Additional tests may include electron microscopy and PCR panels.
Stability testing should be performed at defined intervals: typically 0, 3, 6, 12, 24, and 36 months, with extended testing every 1-2 years thereafter. Two vials per timepoint is standard for viability assessment, sterility, and cell characterization.
Sum the total production batches across all clinical phases and commercial manufacturing, then divide by the number of batches per WCB campaign. Add a safety margin of 10-20% for failed batches and re-derivations.
For CHO cells, the standard is 1x10^7 cells per vial in 1 mL with 10% DMSO. HEK293 and hybridoma cells are typically frozen at 5x10^6 cells/vial. E. coli glycerol stocks are prepared at OD600=1 in 1 mL with 15-25% glycerol.
Under ICH Q5D the Master Cell Bank (MCB) is created once under GMP conditions and fully characterized for identity, purity, genetic stability, and adventitious agents (sterility, mycoplasma, and viral testing), supported by documented history and provenance plus long-term stability data. The Working Cell Bank (WCB) is derived from the MCB and requires only a reduced test panel, because MCB characterization already establishes the lineage. Retention samples are kept for both the MCB and the WCB.
Thaw the vial rapidly in a 37 C water bath, typically in under 2 minutes and until only a small sliver of ice remains. Then dilute the DMSO slowly into pre-warmed medium to avoid osmotic shock, and handle the cells gently throughout. Target post-thaw viability is roughly >85% for CHO and >80% for HEK293, confirmed at the 24 h recovery check.