Many cell lines look identical when viewed under a microscope. Cell lines with very different origins and biological characteristics typically cannot be separated on grounds of morphology or culture characteristics. Infection or contamination of a cell line with an adventitious virus or mycoplasma may not be apparent even when cells are viewed under a microscope but can significantly change the characteristics of the cells. Cell lines may also change with time in culture, and in addition to these naturally-occurring hazards, it is all too easy to incorrectly label or cross-contaminate different cell lines in a busy cell culture laboratory. The opportunities for inadvertently introducing error into a cell line are limitless and ever present. It is in the nature of the science that once introduced, an error will be propagated, compounded, consolidated and disseminated.
The integrity and biological characteristics of a cell line have to be actively maintained by a well-organized management system based on systematic cell banking supported by testing regimens in a structured quality assured environment. Such a controlled environment will only prevail in a dedicated professionally organized cell culture laboratory or cell bank. A small research laboratory with a high throughput of short-term research students, a minimum of permanent laboratory staff and no formal quality management program will find it difficult to maintain its cell lines unchanged over many years.
For all these reasons it is recommended that new cell lines should ideally be acquired from a specialist, reputable culture collection such as ECACC. The European Collection of Authenticated Cell Cultures (ECACC) is one of the world’s largest Biological Resource Centers supplying a diverse range of authenticated cell lines. Moreover, if a laboratory believes it already has a certain cell line in its liquid nitrogen store, the identity and purity of such a cell line should be questioned in the absence of a well recorded culture history and recent test data. If there is a doubt, it is straightforward and cost effective to replace such cell stocks with authenticated material from a culture collection.
When a culture collection acquires a new cell line it will characterize the cell line using techniques such as STR profiling, DNA barcoding and SNP analysis so that the identity of the cell line can be subsequently verified. The collection will then establish a hierarchy of Master and Working cell banks, cryopreserved in liquid nitrogen, that are demonstrated free from microbial contamination including mycoplasma. Researchers are supplied from the authenticated Working cell banks (WCB). Replacement WCBs are manufactured from the original Master cell bank (MCB) and the new WCB will again be tested.
ECACC supplies its cell lines along with product information containing advice on how to maintain the line. The technical support team can subsequently assist with difficulties and provide additional technical information about the cell line, if required. Culture collections exist to ensure that cell research is conducted using standardized and authenticated material that ensures the work can be reproduced. An authenticated cell line of known provenance is the very bedrock of any cell-based project.