Introduction
Authentication is the process by which the true origin and identity of cell lines are determined and should form an essential part of any cell culture operation. The consequences of working with a cell line that is misidentified or cross-contaminated with cells from a different origin can have devastating effects such as invalidating results, devaluing products, years of research made irrelevant and the high costs involved in repeating such work.

Resources and Technology
Over the years of its existence ECACC has developed a wealth of experience in authentication techniques and was in fact one of the pioneering Collections in the world to introduce molecular methods of authentication (1,2). Experienced scientists within ECACC’s Quality Control department are responsible for implementing stringent authentication procedures prior to release of cell lines for distribution.
ECACC uses a combination of methods for authentication to ensure that the cell banks manufactured for distribution are identical to the original seed stock provided by the depositor. These methods include:

• Isoenzyme analysis - good for species verification but cannot differentiate between cell lines of the same species.
• Multilocus DNA Fingerprinting - utilises the original multilocus Jeffries probes and is able to differentiate between cell lines of same and different species. This method produces complex banding patterns which cannot be easily digitalised.
• Short Tandem Repeat (STR) PCR profiling - generates multiple PCR amplicons each incorporating a unique fluorescent marker. This method is quicker and simpler to use producing a profile which is less complex than the multilocus one allowing it to be recorded digitally therefore creating a database of cell line profiles. This enables each new profile to be compared against stored profiles particularly against common known contaminants such as HeLa. Currently this method can only be applied to human cell lines.

Capability
In addition to authentication of its own cell banks ECACC is able to offer this technology as a contract service to authenticate researchers own cell lines. ECACC also offers advice on a consultancy basis in order to put together authentication strategies for clients cell culture operations.

The STR PCR profiling is also employed by ECACC for authentication of its EBV immortalisation service whereby DNA from the resultant lymphoblastoid cell line is compared to DNA extracted from the original blood.
 
References
1. Stacey,G. N. et al (1992) Multilocus DNA fingerprint analysis of cell banks: Stability studies and culture identification in human B-lymphoblastoid and mammalian cell lines. Cytotechnology. 8, 13-20
2. Stacey, G. N., Bolton B. J., and Doyle A (1992) DNA fingerprinting transforms the art of cell authentication. Nature. 357, 261-262