The Value of Isoenzyme Analysis in Cell Bank Characterization

The ICH Q5D guidance notes on cell substrates addresses quality issues related to the properties of the cells used to prepare the biological products “it is well established that the properties of the cell substrate and events linked to the cell substrate can affect resultant product quality and safety and, further, that effective quality control of these products requires appropriate controls on all aspects of handling the cell substrate.” 1 Many procedures are utilized during the production of a cell substrate for the production of a biological molecule or vaccine and these are listed in ICH Q5D and include “cell fusion, transfection, selection, colony isolation, cloning, gene amplification, and adaptation to specific culture conditions or media.” Furthermore the guidance requires that there is a clear history documented during cell production. Typically a cell substrate will be produced, stored and used based on a cell bank system consisting of a master cell bank (MCB), working cell bank (WCB) and an end-of-production cell bank.1 Cell line identification is central to both good quality research and quality control of cell banks and is generally applied to the MCB and the WCB. This tenet came to light after identification of significant cross-contamination of continuous cell lines; isoenzyme analysis was used to show that 20 commonly used human cell lines were contaminated by HeLA cells.”2,3 (Gartler, 1967, 1968). An interesting history and summary of the approaches to tackle cross-contamination and misidentification of cells has been published 4 and its author suggests up to 15% of mammalian cultures were affected at one time.4 The main approaches to authenticating cell line types, species and identity, were and are done, through simple morphology, karyotyping, immunological methods, various molecular techniques such as DNA fingerprinting, random amplified polymorphic DNA (RAPD) and for species of origin most frequently by isoenzyme pattern analysis. There are commercially available kits for isoenzyme analysis and they provide a rapid, robust method to confirming the species of origin of the cells, in addition the analysis can detect the presence of cross-contaminating cells (Nims et al., 1988). Advances in molecular diagnostic techniques, particularly DNA fingerprinting technology have made it possible to authenticate cell lines to the specific individual level as against isoenzyme profiling which cannot be used easily to distinguish between same species cells. Single nucleotide polymorphisms (SNP) and single tandem repeat (STR) profiling, under the umbrella of matured DNA fingerprinting, are now considered to be valid options for standardizing human cell authentication (Nims et al., 2010). You can also read more about Biosafety testing and Bioassay Development. This article is published on behalf of BioOutsource - Europe's fastest growing contract testing organization based in Glasgow, Scotland. Providing contract testing services including Biosimilars Testing, Biologics Testing, Bioassay Development and Vaccine testing services. Reference(s): 1. ICH Topic Q 5 D Note for Guidance on Quality of Biotechnological Products: Derivation and Characterisation of Cell Substrates Used for Production of Biotechnological/Biological Products (CPMP/ICH/294/95). 2. Gartler, S. M. (1967). Genetic Markers as Tracers in Cell Culture. National Cancer Institute Monograph, 26: 167. 3. Gartler, S. M. (1968). Apparent HeLa Cell Contamination of Human Heteroploid Cell Lines. Nature, 217: 750. 4. Nardone RM. (2008). Curbing Rampant Cross-contamination and Misidentification of Cell Lines. BioTechniques, 45: 221. 5. Nims RW et al., (1988) Sensitivity of Isoenzyme Analysis for the Detection of Interspecies Cell Line Cross-Contamination. In Vitro Cell. Dev. Biol. Animal, 34:35. 6. Nims RW et al. (2010). Short Tandem Repeat Profiling: Part of an Overall Strategy for Reducing the Frequenting of Cell Misidentification. In Vitro Cel.l Dev. Biol. Animal. 46:811.