With the advantage of clear target and little side effect, antibody drug has attracted widely attention of worldwide pharmaceutical companies. However, large scale mammalian cell culture and antibody quality analysis are the bottlenecks of antibody drug industrialization in China. Especially due to the significant effect of cell culture conditions on antibody heterogeneity. Therefore, it is extremely urgent to optimize cell culture conditions to favor the demands of antibody drug development. This review summarized the most recent advances in the effect of cell culture conditions on antibody quality, followed by addressing the key issues that might be strategically important for domestic antibody drug development.
Animals ; Antibodies, Monoclonal ; biosynthesis ; isolation & purification ; Antibody Formation ; Cell Culture Techniques ; methods ; trends ; Genetic Heterogeneity ; Protein Stability ; Quality Control

Objective To investigate the expression of regulators of G protein signaling(RGS), including RGS2, RGS3 and RGS4 in OLETF rats, as well as the effects of metformin on these expressions. Methods LETO rats were used as control group. Eight-week-old male OLETF rats were assigned to two guoups randomly:model and trial(metfomin dose during 8~(th) to 22~(nd) weeks:300mg kg~(-1)·d~(-1);during 23rd to 28th weeks:400 mg·kg~(-1) ·d~(-1))groups. Expressions of RGS mRNA in aorta and heart werequantified by real-time PCR. Results RGS2, RGS3 and RGS4 mRNA of the thoracic aorta and left ventricle were significantly higher in model group than in control group (P<0.01). Compared with model group, metformin significantly reduced their mRNA in trial group (P<0.01). Conclusions Upregulation of RGS2, RGS3 and RGS4 mRNA expression in the thoracic aorta and left ventricle of OLETF rats is in correlation with cardiovascular lesions; while downregulation of their expression is in correlation with the action of metformin.

Background: Maedi/Visna virus (MVV) is a contagious viral pathogen that causes considerable economic losses to the sheep industry worldwide. Objectives: In China, MVV has been detected in several regions, but its molecular characteristics and genetic variations were not thoroughly investigated. Methods: Therefore, in this study, we conducted next-generation sequencing on an MVV strain obtained from northwest China to reveal its genetic evolution via phylogenetic analysis. Results: A MVV strain obtained from Inner Mongolia (NM) of China was identified. Sequence analysis indicated that its whole-genome length is 9193 bp. Homology comparison of nucleotides between the NM strain and reference strains showed that the sequence homology of gag and env were 77.1%–86.8% and 67.7%–75.5%, respectively. Phylogenetic analysis revealed that the NM strain was closely related to the reference strains isolated from America, which belong to the A2 type. Notably, there were 5 amino acid insertions in variable region 4 and a highly variable motif at the C-terminal of the surface glycoprotein (SU5). Conclusions The present study is the first to show the whole-genome sequence of an MVV obtained from China. The detailed analyses provide essential information for understanding the genetic characteristics of MVV, and the results enrich the MVV library.

Agitation plays an important role in the hyaluronic acid (HA) fermentation process. However, views about the effect of agitation on HA production remain controversial. We investigated the effect of agitation on cell growth and HA synthesis during HA fermentation process by using Computational Fluid Dynamics (CFD) technology. The results showed that the biomass and HA yield changed a little with the increase of impeller speed, but the HA molecular weight firstly increased and then decreased. The results of phase agitation control strategy demonstrated that the influence of agitation on the HA molecular weight mainly exhibited at the stage of HA synthesis. Moreover, the CFD simulation results indicated that when impeller speed increased, the mixing time reduced while the shear rate increased significantly. The removal of anchor could moderate the contradiction between the mixing time and shear rate, and finally the HA molecular weight increased by 23.9%. The results of this work could provide guidelines for optimizing the HA fermentation, as well as the bioreactor design and scaling up.
Bioreactors ; Fermentation ; Hyaluronic Acid ; biosynthesis ; chemistry ; Hydrodynamics ; Numerical Analysis, Computer-Assisted ; Shear Strength ; Streptococcus equi ; growth & development ; metabolism