Biomedical Engineering Reference
In-Depth Information
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Post-translational modifi cations, in particular glycosylation patterns, can be incomplete and/or
can differ very signifi cantly from patterns associated with native human glycoproteins.
Therapeutic proteins successfully produced on a laboratory scale in insect cell lines include hepa-
titis B surface antigen, IFN-γ and tPA. To date, no therapeutic product produced by such means
has been approved for human use. Two veterinary vaccines, however, have: 'Bayovac CSF E2' and
'porcilis pesti' are both subunnit vaccines (Chapter 13) containing the E2 surface antigen protein
of classical swine fever virus as active ingredient. The vaccines are administered to pigs in order to
immunize against classical swine fever; an overview of their manufacture is provided in
Figure
5.3.
Culture of insect (
Spodoptera
frugiperda
) cells
Addition of recombinant baculovirus
vector
Removal of insect cells from product-
containing extracellular fluid
(centrifugation/filtration)
Addition of viral inactivating agents
Preparation of product-containing oil in
water emulsion
Adjustment of product potency and
excipient addition
Product fill
Figure 5.3
Generalized overview of the industrial-scale manufacture of recombinant E2 classical swine-
fever-based vaccine, using insect cell culture production systems. Clean (uninfected) cells are initially cul-
tured in 500-1000 l bioreactors for several days, followed by viral addition. Upon product recovery, viral
inactivating agents such as beta propiolactone or 2-bromoethyl-imminebromide are added in order to destroy
any free viral particles in the product stream. No chromatographic purifi cation is generally undertaken, as
the product is substantially pure; the cell culture medium is protein free and the recombinant product is the
only protein exported in any quantity by the producer cells. Excipients added can include liquid paraffi n and
polysorbate 80 (required to generate an emulsion). Thiomersal may also be added as a preservative. The fi nal
product generally displays a shelf life of 18 months when stored refrigerated
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