| Abstract |
For the last 15 years, the viral vaccine manufacturing sector is looking
for new producer cell lines, easily scalable, highly permissive to various
viruses, and more effective in term of viral productivity. One critical
characteristic for such cell lines is their ability to grow in suspension
in serum free conditions at high cell densities. Regarding the pathogens
under focus, influenza virus causing severe epidemics both in human and
veterinary field is an important threat for world healthcare. The
manufacturing sector is still demanding effective production processes to
replace/supplement embryonated egg-based process and to provide efficient
response to such threats. Cell-based production, with a focus on avian
cell lines, is one of the promising solutions. Indeed, three avian cell
lines; namely duck EB66 cells (Vivalis), duck AGE.CR cells (Probiogen)
and quail QOR/2E11 cells (Baxter), are now competing with traditional
mammalian cell platforms used for influenza vaccine productions (Vero and
MDCK cells) and are currently at advance stage of commercial development
for the manufacture of vaccine and biologicals.
The DuckCeltTM-T17 derived line presented here is a novel avian cell line
developed by Transgene SA. To generate immortalized duck cell lines,
Transgene has used its proprietary DuckCelT technology which consisted in
constitutively expressing the duck telomerase reverse transcriptase
(dTERT) in primary embryo duck cells from spf eggs.
DuckCeltTM-T17 cells were able to grow in batch suspension cultures and
serum-free conditions up to 7 x 106 cell/ml and such growth was easily
scalable in bioreactors up to 3L. Permissivity for different viruses
including influenza has been evaluated. In the present study, DuckCeltTM-T17
cell line was tested for its abilities to produce various influenza
strains from different origins; human, avian and porcine. All strains were
satisfyingly produced with titres higher than 5.8 log TCID50/ml. H1N1
human strains and H5N2 and H7N1 avian strains were the most efficiently
produced with highest titres reached of 8 log TCID50/ml. Porcine strains
were also greatly rescued with titres of 4 to 7 log TCID50/ml depending of
the subtypes. Interestingly, maximal titres are reached at 24h post-
infection, allowing to have early harvest time.
Process optimization on H1N1 2009 Human Pandemic strain allowed to
identify best operating conditions for production (MOI, trypsin
concentration, medium and density at infection) allowing to improve the
production level by 2 log.
|
|---|
