Altered Band Pattern from Excessive Cell Passage (Western Blot (Unexpected Multiple Bands))

Question

Accepted Answer

Band patterns differ from expected or previously observed results when using cell lines that have been maintained in culture for extended periods. Multiple unexpected bands or altered expression levels appear compared to earlier passages. Common causes: 1) Accumulated genetic drift in frequently passaged cell lines alters protein expression 2) Selection pressure in culture favors cells with altered phenotypes 3) Epigenetic changes accumulate over multiple passages 4) Cell line contamination or misidentification at high passage numbers Solutions: 1) Return to early passage cell line stocks (ideally passage <10-15) 2) Run parallel comparison between early and late passage samples to document differences 3) Establish fresh working stocks from original authenticated cell line source 4) Implement cell line authentication (STR profiling) to confirm identity 5) Maintain passage number records and set maximum passage limits for experiments