Tips on Maintaining High Standards in Cell Culture: How to Avoid the Spreading Problem of Cell Line Contamination
Nicholas Miliaras, Ph.D.
Cell line contamination and/or misidentification has been a persistent issue in life science research over the years and has led to several journal article retractions due to the inability to confirm results. In recent months, many journal editors have begun to require confirmation of cell line identity via accepted methods such as STR profiling. However, to minimize the possibilities of cell line contamination in the first place, ATCC recommends the following best practices:
What to Avoid • Getting cell lines from colleague “down the hall” • Extensive passage of working cell banks • Co-culture with inactivated feeder layer • Selection pressures (pH, temperature, confluence, media formulations) • Mislabeling of culture flasks • Working with multiple cell lines concurrently
What to Do • Obtain authenticated cells from a trusted source • Institute good documentation and training • Have good aseptic technique • Use one reservoir of medium per cell line • Use aliquot stock solutions/reagents • Quarantine new/unauthenticated cell until authenticated master and working cell banks have been established • Work with one cell line at a time in biological safety cabinet • Clean biological safety cabinet and allow time for decontamination between each cell line • Regularly perform STR profiling!
In order to perform STR profile analyses that yields consistently reliable results and data interpretation, a facility needs to establish a robust set of quality-controlled processes including: • Fully validated procedure and training for STR technicians • Setting the required analytical threshold for interpreting results • Use of appropriate controls (positive and negative) • Ability to evaluate internal lane size standards and allelic ladders • Ability to assign alleles to appropriate peaks or bands • Ability to determine appropriate peak height or peak threshold • Ability to detect and resolve artifacts, i.e. stutter peaks, dye blobs, dye pull-ups, microvariants, off-ladder alleles, etc.
-- Nicholas Miliaras, Ph.D., is cell biology specialist at ATCC.