| Summary: | <p>Abstract</p> <p>Background</p> <p>The establishment of high producer is an important issue in Chinese hamster ovary (CHO) cell culture considering increased heterogeneity by the random integration of a transfected foreign gene and the altered position of the integrated gene. Fluorescence-activated cell sorting (FACS)-based cell line development is an efficient strategy for the selection of CHO cells in high therapeutic protein production.</p> <p>Results</p> <p>An internal ribosome entry site (IRES) was introduced for using two green fluorescence protein (GFP) fragments as a reporter to both antibody chains, the heavy chain and the light chain. The cells co-transfected with two GFP fragments showed the emission of green fluorescence by the reconstitution of split GFP. The FACS-sorted pool with GFP expression had a higher specific antibody productivity (<it>q</it><sub>Ab</sub>) than that of the unsorted pool. The <it>q</it><sub>Ab</sub> was highly correlated with the fluorescence intensity with a high correlation coefficient, evidenced from the analysis of median GFP and <it>q</it><sub>Ab</sub> in individual selected clones.</p> <p>Conclusions</p> <p>This study proved that the fragment complementation for split GFP could be an efficient indication for antibody production on the basis of high correlation of <it>q</it><sub>Ab</sub> with reconstitution of GFP. Taken together, we developed an efficient FACS-based screening method for high antibody-producing CHO cells with the benefits of the split GFP system.</p>
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