A molecular approach to the identification and individualization of human and animal cells in culture: Isozyme and allozyme genetic signatures

Abstract

The electrophoretic resolution of a group of genetically monomorphic gene-enzyme systems that are developmentally and biologically ubiquitous has been used to provide a species-specific and type-specific biochemical characterization of various cultured cells. The relative mobilities of gene-enzyme systems representing nine distinct gene products from cell cultures of 25 species from Drosophila to man are presented. These isoenzymes effectively discriminate interspecies cell-to-cell contamination and almost invariably serve to identify the contaminating species. The resolution of eight polymorphic gene-enzyme systems in human cell cultures provides a virtually unique allozyme genetic signature as a monitor of intraspecies cellular contamination. The genetic signatures of 47 commonly used human cells are presented. Included in the test were seven putative HeLa (human cervical carcinoma) contaminants each of which expressed a signature identical with that of HeLa. The probability that an unrelated human cell line will have a signature identical to a typed cell is computed for each line from the genotypic frequencies at each locus in a population of cultured human cells. The gene frequencies of this cell population are comparable to the same frequencies in natural human populations. The most common human signature has a frequency (and therefore a probability) of 0.02. The majority of the 17,010 possible signatures are far less probable. A calculation of the theoretical incidence of chance matching of signatures within test groups of two or more individuals is presented. The probability of a chance match between any two randomly selected individuals is 0.004 and among five randomly selected individuals is 0.034. The allozyme genetic signature represents a definitive monitor of cell identity and is presented as a standard of cell and tissue identification for a variety of biological studies.

Establishments and Biological Characteristics of Melanoma Culture Cell Lines Derived from Aged Gray Horses.

“…The starch-gel electrophoresis technique -a modification of the method of O'brien [12]-was applied. Samples were electrophoresed with a Barbital buffer (pH 7.5); sodium barbital 8.85 g/l, barbital 1.3 g/l, NaCl 0.5 g/l, EDTA-2Na 0.35 g/l and sucrose octaacetate 0.35 g/l.…”

Species identification and authentification of human and rodent cell cultures using polymerase chain reaction analysis of vomeronasal receptor genes

“…However it is also imperative to routinely monitor cell lines for possible contamination using characteristics that authenticate their identity. Over recent decades several methods have been established for use in authenticating and characterising cell lines, including allozyme and isoenzyme analysis (Stacey et al 1997;O'Brien et al 1980), karyotyping analysis (Rush et al 2002), human leukocyte antigen typing (O'Toole et al 1983), immunophenotypic and immunocytochemical analysis (Quentmeier et al 2001), DNA fingerprinting and short tandem repeat profiling (Stacey et al 1992;Dirks et al 2005;Yoshino et al 2006;Azari et al 2007). In general these methodologies can be relatively time consuming and expensive as well as requiring experienced personnel to undertake them.…”

Cell culture forensics

“…However, we wondered whether cell lines other than HeLa were also getting mixed up. To help uncover these, my own group developed the ''allozyme genetic signature'' assay for cells, which determines the composite genotype of seven polymorphic enzyme loci (10,11). By conSee companion article on page 8012.…”

“…12 and 13) as the multiplication product of the included allozyme genotype frequencies. (11). The allozyme approach seemed robust in most cases but suffered when multiple cell lines were considered.…”

“…The allozyme approach seemed robust in most cases but suffered when multiple cell lines were considered. Although the likelihood of a match was about 0.004 (the average composite genotype frequency) for two cell lines, there was a 50% chance of a match when 21 cell lines were genotyped and compared with each other (11,14). This imprecision in designing a unique cell line genetic profile was assuaged somewhat by supplementary karyology and HLA typing with the allozyme signature, but until the dawn of DNA technologies in the 1980s, the resolution was limited and subject to some uncertainty because of statistical creep (likelihood of a chance match) with multiple tests.…”