Amino Acid Sequence Variants in Biotherapeutic Products May Arise from Cell Line Instability

摘要

In this case, comparative analysis of MS data was found to be a critical requirement for detection of a specific amino acid variant, showing that "blind spots" may be present in workflows that rely exclusively on DDA MS/MS methodology. The analytical workflow developed to support cell line development was able to effectively detect and identify this variant, and would allow it to be removed from the clone selection process in a live cell line construction project. The observation that an amino acid sequence variant can occur at an abundance of 1.7% in late generation cultures while remaining undetectable at early generation numbers has implications for cell line development programmes. Routine use of this analysis type in cell line stability studies is recommended to minimise overall project risk in process development. Several potential mechanisms have been reported for how amino acid sequence variants can arise, including genomic DNA mutation, mistranslation at specific codons and nutrient depletion [1]. The exact mechanism of the observation reported here is under investigation and may shed light on the nature of the instability described here.