Abstract:
To improve the transient gene expression of a mousederived antiallergy fusion protein (mAAFP) in 5 L bioreactor, feeding and mild hypothermia were adopted together to provide sufficient nutrition for cell growth and extend the production duration. Firstly, two different expression vectors of pCImAAFP and pIDmAAFP were transiently transfected in CHOS cells with an optimal transient transfection protocol and a better level of mAAFP expression was reached when using pIDmAAFP as an expression vector. Transient gene expression (TGE) was conducted in 1.3 L bioreactor, with combined use of fedbatch and mild hypothermic culture, so the expression level of mAAFP was increased 8fold compared with batch culture. Finally, the TGE process was carried out in a 5 L bioreactor and a high expression level of 25 mg/L was achieved. mAAFP was subsequently purified by rProteinA Sepharose Fast Flow. The obtained mAAFP was identified by SDSPAGE and Western blot. This work provided the necessary basis to assay mAAFP efficacy in mouse later on.