title: Application of statistical techniques for elucidating flow cytometric data of batch and fed-batch cultures.
abstract: The objective of this work is to develop structured, segregated stochastic models for bioprocesses using time-series flow cytometric (FC) data. To this end, mammalian CHO cells were grown in both batch and fed-batch cultures, and their viable cell numbers (VCDs), monoclonal antibody (MAb), cell cycle phases, mitochondria membrane potential/mitochondria mass, Golgi apparatus, and endoplasmic reticulum (ER) were analyzed. For the fed-batch mode, soy hydrolysate was introduced at 24-H intervals. The cytometric data were analyzed for early indicators of growth and productivity by multiple linear regression analysis, which involved taking into account multicollinearity diagnostics, Durbin-Watson statistics, and Houston tests to determine and refine statistically significant correlations between categorical variables (FC parameters) and response variables (yield parameters). The results indicate that the percentage of G1 cells and ER was significantly correlated with VCD and MAb in the case of batch culture, whereas for fed-batch culture, the percentage of G2 cells and ER was correlated significantly. There was a significant difference between cells in the batch and fed-batch cultures in their ER content, suggesting that the increase in protein synthesis as reflected by the ER content and consequent increase in growth rate and MAb productivity both can be monitored at the cellular level by FC analysis of ER content.
authors.affiliation: School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Nishikant
authors.initials: N
authors.lastname: Shirsat
authors.forename: Mohd
authors.initials: M
authors.lastname: Avesh
authors.forename: Niall J
authors.initials: NJ
authors.lastname: English
authors.forename: Brian
authors.initials: B
authors.lastname: Glennon
authors.forename: Mohamed
authors.initials: M
authors.lastname: Al-Rubeai
mesh_terms: D000818:Animals; D061249:Batch Cell Culture Techniques; D016466:CHO Cells; D003412:Cricetulus; D005434:Flow Cytometry / Q000379:methods*; D013223:Statistics as Topic; D013269:Stochastic Processes
keywords: CHO; cell cycle phases; endoplasmic reticulum; fed-batch; flow cytometry; hypothesis testing; stepwise multivariate analysis