eBook: Cell and Gene Therapy - 6

In Chapter 3 of this eBook, we describe three cell
lines optimized to produce high-titer viral stocks.
These cell lines have either the STAT1 gene (encodes
for proteins involved in viral-induced apoptosis)
knocked out or both the STAT1 and BAX
genes (encodes for antiviral immune responses)
knocked out via CRISPR/Cas9 gene editing. These
cell lines produce viral titers 10-fold higher than
those of the parental cell lines.12
These cells represent
a powerful tool for enabling biopharmaceutical
companies to achieve the viral titers necessary
for scaled production of gene therapies and antiviral
vaccines.
Making safer biologics by detecting
contamination earlier
Biologics such as recombinant proteins and monoclonal
antibodies comprise a significant proportion
of bio-based therapeutics. Their production may
be achieved using bacterial or mammalian cell
lines,14
each with their own advantages and disadvantages.
Mammalian cell lines-which are used in
the production of viruses needed for gene therapy
and antiviral vaccine development-are notorious
for their susceptibility to contamination. Reports
indicate that 15-35% of continuous cell cultures
suffer from contamination by mycoplasma,15
an
environmentally ubiquitous and notoriously difficult-to-detect
group of bacteria that can also contaminate
bacterial cell cultures.
Rapid and early mycoplasma detection is critical
to protect cell lines used in biologics production
to ensure contaminated therapies don't reach patients.
The gold-standard combination of detection
methods-culture-based assays and DNA staining
with fluorochromes-is tedious, time-consuming,
expensive, and difficult to interpret. However, for
alternative assays to be accepted, they must be
thoroughly tested to demonstrate sensitivity for
mycoplasma detection.
In Chapter 4 of this eBook, we describe the evaluation
of qPCR and droplet digital™ PCR (ddPCR; BioRad®)
methods for mycoplasma detection by using
quantitative mycoplasma DNA certified reference
materials.16
Both platforms proved to be sensitive
for the detection of mycoplasma DNA concentrations
as low as 1 genome copy. This work provides
a framework for effectively and thoroughly evaluating
new molecular-based mycoplasma detection
methods for ensuring the sterility of final product.
Ensuring the quality and safety
of biologics
Quality and safety are also critical considerations
every step of the way. A variety of resources exist
to ensure the quality and safety of the biologics
you produce. For example, control human primary
immune cells17
support a range of assays for cytotoxicity,
transplantation and graft rejection, and
inflammation and allergy to ensure the safety of a
range of biologics. Similarly, adenovirus reference
standard materials (RSMs) for gene therapy have
been developed for potency testing and to calibrate
virus vector standards within individual laboratories,18
data
produced at a variety of locations-improving
both preclinical and clinical meta-analyses.
The future is now
A sustainable, healthy future depends on the success
of our bioeconomy, and a significant portion
of our bioeconomy is focused on bio-based therapeutics
such as cell and gene therapies, vaccines,
and other biologics as covered in Chapter 5 of this
eBook. We hope this eBook is a useful resource to
facilitating accurate cross-comparison of
6
eBook: Cell and Gene Therapy

Table of Contents for the Digital Edition of eBook: Cell and Gene Therapy
