Quality Control Considerations

Introduction

Quality is important in all aspects of tissue culture since the quality of materials used i.e. media and other reagents) will affect the quality of the cultures and products derived from them. The main areas of quality control that are of concern for tissue culture are:

*The quality of the reagents and materials

*The provenance and integrity of the cell lines

*The avoidance of microbial contamination

1.Reagents and Materials

A potential source of contamination is reagents and materials, in particular bovine serum which has been identified as a source of bovine viral diarrhoea virus (BVDV). Porcine trypsin is also a potential source of Mycoplasma hyorhinis. Good quality reagents and materials are available from numerous manufacturers of tissue culture media and supplements. In addition manufacturers including Sigma will carry out a range of quality control tests including screening for mycoplasma and BVDV and supply a Certificate of Analysis with their products. These state the product and lot numbers and forms a vital part of record keeping and tracking of reagents used in the production of cell stocks. It is advisable to further test key reagents such as FBS to ensure that they are ‘fit for purpose’ due to batch-to-batch variation.

Manufacturers of sterile plastic ware (flasks, centrifuge tubes, pipettes) designed for tissue culture use are also supplied with Certificates of Analysis for each batch produced, which should be kept for future reference.

2.Provenance and Integrity of Cell Lines

The sourcing of cell lines can have an important effect on quality since freshly imported cell lines are a major source of contamination. The advantages of obtaining cell lines from a recognized source such as a culture collection are:

Contaminant free

Fully characterized and authenticated in terms of DNA profile and species of origin

Supplied with a detailed data sheet

Once cell lines have been obtained from a reputable source it is important to implement master and working cell banking procedures and the associated quality control steps such as routine testing for microbial contaminants and confirming the identity of cultures.

3.Avoidance of Microbial Contamination

Potential sources of contamination include other cell lines, laboratory conditions and staff poorly trained in core areas such as aseptic techniques and good laboratory practice. Thus the use of cells and reagents of known origin and quality alone is not sufficient to guarantee quality of product (cell stock or culture products); it is necessary to demonstrate quality throughout the production process and also in the final product. Routine screening aids the early detection of contamination since all manipulations are a potential source of contamination.