Avian Influenza Virus
Most avian influenza viruses do not cause disease in humans. However, some are zoonotic, meaning that they can infect humans and cause disease. The most well known example is the avian influenza subtype H5N1 viruses currently circulating in poultry in parts of Asia and northeast Africa, which have caused human disease and deaths since 1997. (cited from wikipedia)
Influenza viruese could be well expressed in TideCell high-density cell culture system and achieve 4 folds HA increase than in roller bottles (1024 to 2048).
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No.
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Process Character
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How TideCell supports the process requirement?
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Can other systems do the same?
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1.
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High cell density is required to achieve high titer, and reduce medium consumption.
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High surface area provided in TideCell increase cell density up to 10 folds and save culture medium up to 90%.
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Microcarrier stir tank
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No. the bead density is limited
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Fixed bed bioreactor
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Yes, but the scale is limited.
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2.
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Cell attachment efficiency is low due to long term trypsinization.
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A relative static seeding method enable high attachment rate even the cells have been over-trypsinized.
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Microcarrier stir tank
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No. An agitation environment increase the difficulties of cell attachment. The cell attachment efficiency will become lower when the scale is increased.
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Fixed bed bioreactor
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No. An agitation environment increase the difficulties of cell attachment.
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3.
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Cells tend to detach after infection due to the adding of trypsin
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A gentle and relative static culture method enables a low shear stress culture environment. Cells will be not easy to detach after infection and increase the productivity.
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Microcarrier stir tank
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No. An agitated environment enhance cell detach after infection.
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Fixed bed bioreactor
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No. An agitated environment enhance cell detach after infection.
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4.
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Low DNA and low host cell protein in the harvest is required to reduce the impurties.
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A gentle and relative static culture method enable a low shear stress culture environment. Cells are retained in the matrix without being flushing out. DNA and host cell protein reduces is relatively low in the harvest.
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Microcarrier stir tank
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No. An agitated environment cause cell disruption and release of DNA and host cell protein.
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Fixed bed bioreactor
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No. An agitated environment cause cell disruption and release of DNA and host cell protein.
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5.
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Require to refresh culture medium before infection
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Matrix vessel which is immobilized with cells is separated from mixing vessel containing culture medium. Medium could be exchanged directly without losing cells. Minimum medium add could keep normal operation without causing temperature shock which will not affect virus production performance.
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Microcarrier stir tank
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No. Medium can only be partially replaced by settling the carriers. Nutrient may not be sufficient to support entire post-infection period.
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Roller bottle
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Yes, but medium has to be filled and a temperature shock might occurred.
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Packed-bed bioreactor
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Yes, but medium has to be filled completely and a temperature shock might ocurred especially in a large scale system.
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6.
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Final Achievement
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Virus HA titer: 1024~2048
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Roller bottle
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HA titer: 256
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Fixed bed bioreactor
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HA titer: 1024
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Culture System |
Roller bottle |
NBS BioFlo Bioreactor |
BelloCell |
TideCell |
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Scale |
850 cm2 |
1 L |
100 ml matrix/500 ml medium |
5L matrix/50 L medium |
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Carrier Weight |
850 cm2 |
5 g |
5.5 g |
550 g |
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Type |
Cytodex I |
BioNOC II |
BioNOC II |
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Cell Density (cells/g carrier) |
5.54×108 |
2.36×108 |
3.08×108 |
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Cell Density (cells/ml) |
5×105 |
2.77×106 |
1.3×107 |
2×107 |
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Virus titer (HA/50 ul) |
256 |
1024 |
2048 |
1024 |
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Virus titer (pfu/ml) |
1×108 |
1×109 |
9.2×108 |
7×108 |
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Harvest volume (ml) |
200 |
1000 |
500 |
50000 |
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Equivalency |
1/1000 |
1/50 |
1/50 |
1 |