Keeping a common cell line trustworthy: what a jurkat cell line and the jurkat cell culture protocol around it have to control in density and passage that a plated line does not, why jurkat cells, 293t cells used for lentivirus production, 293t cells lentivirus production work generally, a huh7 cell line, huh7 cells, a549 cells, mda-mb-231 and other everyday lines drift and cross contaminate more than anyone expects, how str analysis and str profiling settle identity where morphology cannot and where routine cell culture analysis will not, why a mycoplasma detection kit belongs on a schedule rather than in a crisis, and what a laboratory should record so a line's history survives the person who cultured it

Running a line properly

1. Control density rather than schedule. Suspension lines have a working density range, and cultures allowed to overgrow change phenotype and respond differently for several passages afterwards. Count and split by density rather than by day of the week.
2. Authenticate identity on arrival and periodically. Short tandem repeat profiling against a reference database is inexpensive and definitive. Run it when a line arrives, before a major study and when anything about the line's behaviour surprises you.
3. Screen for mycoplasma on a schedule. Contamination is common, invisible and changes cell behaviour substantially. Test new arrivals in quarantine and cultures in continuous use on a fixed interval, and keep the results with the line record.
4. Set and enforce a passage limit. Lines change with passage number, and a study running across a wide passage range has an uncontrolled variable in it. Bank early, work from the bank, and return to it rather than culturing indefinitely.
5. Bank properly and split the storage. A frozen bank from a low passage authenticated culture, split across separate storage locations, is what lets a laboratory recover from a contamination or a freezer failure without losing years of work.
6. Record the line's provenance. Where it came from, when, its authentication result, its passage at receipt and its screening history. A line with no provenance is a line whose results cannot be defended.

Misidentification is common and old

A substantial number of lines in circulation are not what their labels say, and many of those substitutions happened decades ago and propagated through sharing between laboratories. Morphology does not detect it and neither does behaviour.

Profiling is the only test that does, and it is cheap. A laboratory that profiles every line once has removed a category of error that otherwise sits under everything it publishes.

Quarantine is the cheapest control

New arrivals handled in a separate incubator, with separate media and a screening test before they join the main culture area, prevent the events that cost laboratories months. It requires space and discipline rather than money.

Write it into the laboratory's procedures with a named owner. Quarantine that depends on whoever remembers is quarantine that will be skipped when a project is urgent.

Common questions

How often should cell lines be authenticated?

On receipt, before publication or a major study, and at least annually for lines in continuous culture. Funders and journals increasingly ask for the evidence, and generating it retrospectively is not possible.

Why do transfection host lines drift?

Continuous passage and selection favour subpopulations, and transfection efficiency is one of the properties that changes. Working from a low passage bank rather than a long running culture keeps the behaviour stable.

Is mycoplasma testing really necessary if cultures look fine?

Yes, because contamination is invisible without testing and alters proliferation, gene expression and drug response. Testing only when something looks wrong means the affected experiments have already been done.

What passage range should be used?

A range narrow enough that behaviour is stable, established for each line rather than assumed. Recording passage number with every experiment is the minimum, and returning to the bank rather than extending a culture is the discipline.

Browse by service class

• Compare Gene synthesis on advertised prices