John R Birch

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We have employed an inverse engineering strategy based on quantitative proteome analysis to identify changes in intracellular protein abundance that correlate with increased specific recombinant monoclonal antibody production (qMab) by engineered murine myeloma (NS0) cells. Four homogeneous NS0 cell lines differing in qMab were isolated from a pool of(More)
Monoclonal antibodies (Mab) are heterotetramers consisting of an equimolar ratio of heavy chain (HC) and light chain (LC) polypeptides. Accordingly, most recombinant Mab expression systems utilize an equimolar ratio of heavy chain (hc) to light chain (lc) genes encoded on either one or two plasmids. However, there is no evidence to suggest that this gene(More)
The clinical and commercial success of monoclonal antibodies has led to the need for very large-scale production in mammalian cell culture. This has resulted in rapid expansion of global manufacturing capacity [1], an increase in size of reactors (up to 20,000 L) and a greatly increased effort to improve process efficiency with concomitant manufacturing(More)
In this study we describe optimization of polyethylenimine (PEI)-mediated transient production of recombinant protein by CHO cells by facile manipulation of a chemically defined culture environment to limit accumulation of nonproductive cell biomass, increase the duration of recombinant protein production from transfected plasmid DNA, and increase(More)
We have developed a simple and robust transient expression system utilizing the 25 kDa branched cationic polymer polyethylenimine (PEI) as a vehicle to deliver plasmid DNA into suspension-adapted Chinese hamster ovary cells synchronized in G2/M phase of the cell cycle by anti-mitotic microtubule disrupting agents. The PEI-mediated transfection process was(More)
The relationship between spot volume and variation for all protein spots observed on large format 2D gels when utilising silver stain technology and a model system based on mammalian NSO cell extracts is reported. By running multiple gels we have shown that the reproducibility of data generated in this way is dependent on individual protein spot volumes,(More)
The folding, transport and modification of recombinant proteins in the constitutive secretory pathway of eukaryotic cell expression systems are reported to be a bottleneck in their production. We have utilised a proteomic approach to investigate the processes catalysed by proteins constituting the secretory pathway to further our understanding of those(More)
We previously compared changes in individual protein abundance between the proteomes of GS-NS0 cell lines with varying rates of cell-specific recombinant monoclonal antibody production (qMab). Here we extend analyses of our proteomic dataset to statistically determine if particular cell lines have distinct functional capabilities that facilitate production(More)
In this study we have analyzed the dynamic covariation of the mammalian cell proteome with respect to functional phenotype during fed-batch culture of NS0 murine myeloma cells producing a recombinant IgG(4) monoclonal antibody. GS-NS0 cells were cultured in duplicate 10 L bioreactors (36.5 degrees C, 15% DOT, pH 7.0) for 335 h and supplemented with a(More)
Mouse hybridoma cells producing a monoclonal antibody to anti-B blood group antigen have been grown in airlift fermenters up to 30 litres capacity. As a prerequisite for scaling the process up, the oxygen utilization rate of the cells has been established by a dynamic method using an oxygen electrode. The data is compared with that obtained from a chemostat(More)