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Vaccine Vectors
Attenuated vaccine vectors are live bacteria or viruses that have been weakened
such that they are no longer capable of causing disease. These attenuated vectors
can be used as vaccines themselves or as a general delivery system that can be used to
develop vaccines against a variety of diseases. Emergent BioSolutions has developed
two universal vaccine delivery vectors; the Salmonella typhi spi-VEC™ bacterial
platform suitable for oral vaccine delivery, and a Modified Vaccinia Ankara (MVA)
viral vector MVAtor™ for injectable vaccines.
spi-VECTM Oral Delivery Platform Description
spi-VEC is Emergent BioSolutions’ proprietary oral delivery technology based on a
live attenuated Salmonella enterica serovar typhi bacterium, (S. typhi; the cause of
typhoid fever) that has been specifically engineered to:
1) Eliminate its ability to cause disease by removing critical virulence-associated genes; and
2) Efficiently express foreign vaccine antigens in a manner designed to lead to a protective immune response.
The spi-VEC delivery platform is based on two independently attenuating and
non-reverting deletions engineered into the S. typhi chromosome, one of which
is designed to prevent systemic spread of the vaccine strain, an important safety
consideration for live vaccines. Genes encoding foreign vaccine antigens are inserted
into the chromosome of the attenuated Salmonella typhi vector (spi-VEC) u
nder the control of a proprietary antigen-expression promoter using recombinant DNA technology.
A commercial scale cGMP manufacturing process culminating in a stable, freeze-dried presentation
for oral administration has already been established for the spi-VEC vector.
spi-VEC Applications
spi-VEC technology is versatile in that it is designed to deliver a wide
range of antigens to prevent or treat numerous diseases, including bacterial and
viral infections and cancer. Our spi-VEC technology is based on our oral
typhoid product candidate.
MVAtor is a registered trademark in Germany, a pending trademark in the European Community and is owned by Emergent.
spi-VEC is a trademark registered in the European
Community and is owned by Emergent.
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