Abstract
Growth hormone deficiency results in growth retardation in children and the GH deficiency
syndrome in adults and they need to receive recombinant-GH in order to rectify the
GH deficiency symptoms. Mammalian cells have become the favorite system for production
of recombinant proteins for clinical application compared to prokaryotic systems because
of their capability for appropriate protein folding, assembly, post-translational
modification and proper signal. However, production level in mammalian cells is generally
low compared to prokaryotic hosts. Taguchi has established orthogonal arrays to describe
a large number of experimental situations mainly to reduce experimental errors and
to enhance the efficiency and reproducibility of laboratory experiments.
In the present study, rhGH was produced in CHO cells and production of rhGH was assessed
using Dot blotting, western blotting and Elisa assay. For optimization of rhGH production
in CHO cells using Taguchi method An M16 orthogonal experimental design was used to
investigate four different culture components. The biological activity of rhGH was
assessed using LHRE-TK-Luciferase reporter gene system in HEK-293 and compared to
the biological activity of prokaryotic rhGH.
A maximal productivity of rhGH was reached in the conditions of 1%DMSO, 1%glycerol,
25 µM ZnSO4 and 0 mM NaBu. Our findings indicate that control of culture conditions such as the
addition of chemical components helps to develop an efficient large-scale and industrial
process for the production of rhGH in CHO cells. Results of bioassay indicated that
rhGH produced by CHO cells is able to induce GH-mediated intracellular cell signaling
and showed higher bioactivity when compared to prokaryotic GH at the same concentrations.
Key words Mammalian cell lines - Taguchi method - growth hormone - optimization - biological
activity
