Hyaluronan treatment of biotinylated packaging cells increases titre of
progeny retrovirus affinity-captured onto paramagnetic particles.
Abstract
BACKGROUND: The polysaccharide hyaluronan is a major component of the
extracellular matrix and has been observed to impact retrovirus
infectivity in biological settings. Hyaluronan has also been applied in
biotechnology as a non-immunogenic, biocompatible agent to improve
control of drug delivery and lentiviral transduction. We carried out a
preliminary investigation to ascertain if the presence of hyaluronan
influenced titre performance of an engineered retrovirus during the
production, capture and infection steps that constitute key metrics for
retroviral bioprocess performance. RESULTS: The PG13.pBabe.puro stable
packaging cell line constitutively produces retroviral particles with
the gibbon ape leukaemia virus (GaLv) envelope protein and was used here
with HeLa cells for retrovirus titration. An established bench-scale
retrovirus production procedure was investigated in which packaging
cells are chemically biotinylated and progeny retrovirus bound to
streptavidin-coated paramagnetic particles (SPMPs) to achieve both
retrovirus concentration and enhanced retroviral infection of target
cells. Post-biotinylation incubation of PG13.pBabe.puro cells with up to
100μg/mL hyaluronan did not impact the base titre of unconcentrated
progeny retrovirus. Incubation of target HeLa cells with up to 100μg/mL
hyaluronan did not influence the susceptibility of HeLa cells to
infection by retrovirus bound to SPMPs. However, post-biotinylation
incubation of PG13.pBabe.puro cells increased titre of progeny
retrovirus bound to SPMPs by up to 395%. CONCLUSION: These observations
are consistent with the hypothesis that the presence of haluronan after
packaging cell biotinylation increases the efficiency of capture of
biotinylated retrovirus by SPMPs. Further work will be needed to confirm
if this is indeed the case and if packaging cell incubation with
hyaluronan, or related biocompatible carbohydrates, could improve
bioprocess performance of other retro- or lenti- viral vectors in
therapeutic applications.