Working cell bank, WCB

Once the cell line is selected as a host for production, a cell bank system must be generated to guarantee the availability of an adequate source of equivalent cells to use through the product s lifetime in the market. Usually, the cell bank system consists of two levels a master cell bank (MCB) and a manufacturer s working cell bank (WCB). 

Arindam Bose (Pfizer Central Research) further discussed the ICH documents and presented a rationale for the recommended combination of test procedures and process clearance validations required to demonstrate that marketed biopharmaceuticals are free of adventitious agents. He showed that testing of Pre-Seed Stock (PSS), the Master Cell Bank (MCB), and the Working Cell Bank (WCB) is required to demonstrate that they are free from contamination by mycoplasma, bacteria, molds, and yeasts. In addition, viral clearance validation studies must be performed on scaled down versions of each chromatographic step and the viral inactivation/removal step employed in the product purification scheme. Finally, clearance studies must be conducted with a panel of relevant and model viruses (typically three to four) to establish that the purification scheme will indeed purge any viruses that may be inadvertently introduced during processing. 

A master cell bank (MCB) is set up which forms the first generation of these clones. They are stored in hundreds of vials under liquid nitrogen freezers (-150 °C or below) to preserve them indefinitely. From the MCB, a vial is taken and another generation of clones is produced, these constitute the working cell bank (WCB), and they too are maintained in liquid nitrogen freezers. Subsequently, a vial is taken from the WCB for each batch of production. This two-tier system of MCB and WCB can supply production needs indefinitely. For example, 200 vials each of the MCB and WCB for a production rate of 10 batches per year will last 4000 years. 

This has been issued to describe analysis of the expression construct in eukaryotic and prokaryotic cells used for the production of r-DNA-derived protein products [29]. Both the expression construct and the purified final recombinant protein should be characterized. It should thereby be verified that the correct coding sequence has been incorporated and maintained during culture. A master cell bank (MCB) and a working cell bank (WCB) should be considered. Nucleic acid analyses, PCR-based assays and DNA-sequencing are methods to be used. A consistent quality of the final product should be guaranteed. 

Currently, most RTFs and mAbs are expressed in rodent, bacterial or yeast cell cultures (see Part IV, Chapter 13). A Master Cell Bank (MCB) should be estabbshed and tested for authenticity and freedom from contamination [5, 8, 11] (see also Part IV, Chapter 4). A Working Cell Bank (WCB) is extremely useful to extend the lifetime of the MCB. 

Willebrand factor 425, 1153 Wilm s tumor 221, 359 (With-no-lysine) kinase-4 (WNK4) 78 Wnt-binding proteine 294 Wolffian duct 355 Working Cell Bank (WCB) 1645 World Drug Index (WDI) 1790 World Health Organization (WHO) 1569... 

Working cell bank (WCB) Size-exclusion HPEC (SEC-HPEC) Phase 1 studies (healthy... 

LSBL MAP MCB NDA NIH PPC PTC QA QC RAP WCB WCP WHO large-scale biosafety level mouse antibody production master cell bank new drug application National Institutes of Health post-production cells points to consider quality assurance quality control rat antibody production working cell bank well-characterized product World Health Organization... 

Master Working Cell Bank. A detailed description of the working cell bank, or WCB and the cell line used to produce the biologic product must be provided. The production of the WCB should be described in detail. 

LMANl lectin maimose-binding pro- WCB working cell bank... 

Fig. 1.3 Diagram of a simple batch (or extended-batch) process with suspension cells. Cells are obtained from a Master- or Working Cell bank (MCB/WCB) and inoculated into spinners for a defined subcultivation period (every 3—4 days, usually for up to 100 days or more). For maintenance purposes of the culture, the cells in the spinner are referred to as the seed train". Cells...

The resulting stable, homogeneous population of FVIII-expressing cells was used to establish master (MCB) and working (WCB) cell banks for processing the dmg substance [8, 12]. 

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