Identification of cells in culture

Most laboratories using cells cultured in vitro maintain multiple cell lines. Such lines should be monitored for species and intraspecies characteristics to prevent invalidation of research work due to incidents of cell line cross‐contamination. This report describes the results obtained when 246 cell cultures were examined for evidence of cross‐contamination or mislabeling. Using species‐specific antigens, isoenzyme electrophoresis, and chromosomes as markers of identity, 14% of the cultures submitted were found to be contaminated by cells of another species. Of human cell lines submitted 25% were of HeLa cell origin, as determined by 2 intraspecies markers, glucose‐6‐phosphate dehydrogenase and chromosome analyses. The fact that, overall, nearly 30% of the cell lines examined were incorrectly designated makes the importance of cell line monitoring self‐evident.