Advantage of syFISH analysis

  Heterogeneity of cell lines has potential impact on the quality of cell-produced products (biopharmaceuticals) such as monoclonal antibodies. This is why regulatory authorities including FDA and EMA/CHAMP are recommending more stringent control on the monoclonality of the cell lines. Thus, new technological development has been expected to evaluate master cell bank (MCB). 

  Sumika Chemical Analysis Service, Ltd. (SCAS) offers the unique technology, called syFISH (systematic FISH) analysis, for the monoclonality evaluation. syFISH is the combination analysis of FISH (Fluorescence in situ hybridization) and multicolor FISH, and brings detailed information on the chromosome integrated the transgene. FDA introduced syFISH analysis in their presentation document in 2016 as an effective method for monoclonality evaluation of cell lines.

  Mammalian cells such as CHO cells and HEK293 cells are widely used for biopharmaceutical production and known to have unstable karyotypes. Chromosomal rearrangements during cell expansion, cause variation of chromosomal composition, even in a population expanded from a single cell. Due to these features, it is difficult to map the transgene on chromosomes.

  syFISH analysis can provide detailed information on the chromosome of the transgene integration as shown in the pictures below. The clonal status of a cell line is evaluated from the transgene integration sites.

Figure. Mapping of FISH signals on CHO chromosomes with syFISH

syFISH analysis can be applied for various purposes throughout the whole process of cell bank construction, as below.

As presented above, syFISH analysis is again a useful tool for the evaluation of transgene status during cell line development for biopharmaceutical production.