Welcome to the FiberCell Systems fall edition of “Expressions"...
...bringing you all of the latest happenings in the world of hollow fiber bioreactors. FiberMan is getting ready to celebrate the fall harvest but it has been a busy summer for him!
PK/PD Keynote Presentations
Fibercell Systems gave keynote presentations at three Pk/Pd Antibiotic Research meetings this year, in Lisbon, Milan, and Toronto. Antibiotic resistance remains a key issue with the ever-increasing incidence of resistant strains. The Hollow Fiber Infection Model is an invaluable tool for evaluating new indications for current antibiotics, determining dosage profiles that result in resistance and testing two drug models for areas of inhibition and synergy.
Combination therapies may be the immediate future for antibiotics and researchers at Baylor made a major contribution by using the HFIM to optimize a two drug antibiotic regimen for pediatric tuberculosis. TB in children is distributed differently, with more intracellular organisms that are harder to kill. Previous therapies resulted in 25% of the children treated getting a hearing loss as a side effect of the therapy. Dr. Gumbo and Dr. Kant developed a protocol that is more effective using a combination of antibiotics at lower doses, with less toxicity than the single drug therapy.
Difficult-to-express proteins can be proteins that are expressed at low titers by mammalian expression systems. They are also defined as highly complex proteins; highly glycosylated, with high levels of post-translational modifications and in some cases consisting of several subunits. Case studies using hollow fiber bioreactors (HFBR) have demonstrated superior expression of these types of proteins with complete and uniform post-translational modifications, such as hexerimized IgG and the IL15 ligand-receptor complex. The next generation of therapeutic proteins include bi-specific and tri-specific antibodies, protein structures that are the creation of bio-engineers and not found in the templates of nature. These proteins require the in vivo-like cell culture conditions and concentration that HFBRs and mammalian expression systems for proper expression.
KD Bio News
Our sister company in Europe, KDBio, has also been attending meetings over the summer and will present a poster at the French Society for ExtraCellular Vesicles in Paris and also at the UK-EV forum in Birmingham England December 12th, 2017. KDBio is our direct stocking outlet in the European Union and U.K. providing service and support for all of our products.
Secretomic profiling of cells from hollow fiber bioreactor reveals PSMA3 as a potential cholangiocarcinoma biomarker
VERATHAMJAMRAS et al:
International Journal of Oncology DOI: 10.3892/ijo.2017.4024
It is becoming increasingly clear that standard flask culture can be lacking in physiological relevance and that 3-D culture systems, such as a hollow fiber bioreactor (HFBR) from FiberCell Systems, offer a more in vivo-like cell culture environment. A recent paper published in the International Journal of Oncology demonstrates this nicely. Researchers were hoping to identify a circulating diagnostic biomarker for a cancer. A cholangiocarcinoma cell line was cultured in flasks along with being seeded into a 5 kd MWCO hollow fiber bioreactor (Cat # C2008). The flask cultures were maintained with 10% FBS until they were 70% confluent, the medium was replaced with basal medium containing no serum for 24 hours and the conditioned medium, or secretome was collected. The hollow fiber cartridge was maintained with DMEM/10% CDM-HD, a protein free serum replacement optimized for high density, hollow fiber cell culture. The data shows that proteins in the HFBR were not only concentrated by the 5 kd MWCO, but their differential expression demonstrates the effect of the 3-D culture, with one protein being expressed 57 X more than in flask culture. If the proteins were only concentrated, then they should all be increased equally. This protein was also found to be significantly elevated in the plasma of patients with cholangiocarcinoma, showing its usefulness as a diagnostic biomarker.
Above: (A) Western blot detection of secretory proteins from HFB and MNC systems. Results show enrichment of secretory LCP1, ENO1, PSMA3 TPI, PSMA6, DJ1, PSMB6 and NGAL in the HFB system. The loading control was obtained by subsequently staining the membrane with Coomassie blue after the western blotting. (B) Bar graphs represent the expression ratio of the protein intensity (HFB/MNC) detected by western blotting shown as the number values on the top of each bar.
FiberCell Systems has three new articles for download from our website. Topics include "Cell culture in 3-Dimension", "Monoclonal antibody production in hollow fiber bioreactors" and "The use of hollow fiber bioreactors for the production of difficult-to-express recombinant proteins."
Tech Tip: Trick or Treat! Playing serum tricks with hollow fiber bioreactors
There is much interest in the use of basal media without serum for collecting secretomes, as in the article above, or for the production of exosomes without contamination from endogenous serum exosomes. In nearly all cases cells in the hollow fiber bioreactor can be cultured using our CDM-HD, a protein free, animal component free, chemically defined cGMP compliant serum replacement. In the event this is not possible, or desirable, you can use the 20 kd MWCO fiber and use serum in only the circulating medium. The factors in serum that support cell growth can cross the fibers while antibodies, exosomes and other large components cannot.
There is much interest in the use of basal media without serum for collecting secretomes, as in the article above, or for the production of exosomes without contamination from endogenous serum exosomes. In nearly all cases cells in the hollow fiber bioreactor can be cultured using our CDM-HD, a protein free, animal component free, chemically defined cGMP compliant serum replacement. In the event this is not possible, or desirable, you can use the 20 kd MWCO fiber and use serum in only the circulating medium. The factors in serum that support cell growth can cross the fibers while antibodies, exosomes and other large components cannot.
