Objective: The study of physiological changes in recombinant cell lines provides useful information to improve production performance. In this study, we investigate the effects of an anti-CD33 chimeric IgG 4 expression on Sp2.0 cell growth. Methods: Variable region genes of light and heavy chains of monoclonal antibody produced by M195 were cloned in pFUSE-CLIg-hk and pFUSE-CHIg-hG4 expression vectors, respectively. Transfection of recombinant plasmids into Sp2.0 cell lines was performed using

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... ipofectamine in two steps. Positive transformant cells were isolated and subjected to PCR, RT-PCR and Western blot analysis to confirm the integration of gene cassettes and the expression of recombinant IgG 4. To assess the growth parameters, recombinant and parent Sp2.0 cell lines were seeded at a density of 1×10 5 cells/ml in duplicate into 12-well plates. For nine days, culture plates were sampled daily and viable cell count and viability determined. Results: The results of PCR, RT-PCR and Western blot analyses confirmed the generation of stable producer cell lines. In recombinant cells, the maximum cell density decreased by 46%. However, it was observed that IgG 4 expression had no effect on cell viability of these transfectants. Conclusion: Our results showed that the expression of recombinant IgG 4 can change growth parameters in Sp2.0 cell lines that express the pFUSE-CHIg-hG4-pFUSE-CLIg-hk construct.