Characterizing the Expression Stability in Different Phenotypes of Recombinant NS0 Myeloma Cell Lines
The loss of heterologous protein expression is one of the major problems faced by industrial cell line developers and have been reported by several authors. For this reason understanding the mechanisms involved in the generation of stable and high producer cell lines is very important, especially for those processes based on long-term continuous cultures. In this work we have determined the stability pattern of different recombinant NS0 myeloma cell lines after long term culture, and observed the spontaneous generation of clones with different expression patterns. Moreover, we have characterized two types of clones: unstable and stable with respect to extra- and intracellular light (LC) and heavy (HC) chain expression of recombinant monoclonal antibody, i.e. the expression of typical surface markers for myeloma cell lines. Also, we have compared their respective proteomes using two dimensional gel electrophoresis at the start of cell culture and after 40 generations. it was determined that excess light chain was found in both clones. Eight proteins were associated with the stability profile following a comparison algorithm. The unstable clone showed a decreasing pattern of the expression for these proteins, which are mostly related to protein synthesis and folding, membrane transport, cytoskeletal structure as well as energy production.
Key WordsExpression stability Proteomics Recombinant NS0 cells
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