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Microcarrier-Based Expansion of Adipose-Derived Mesenchymal Stem Cells in Shake Flasks

by Khandaker Siddiquee, PhD and Ma Sha, PhD
Volume 12, Issue 4 (Winter 2013/2014)

The expansion of stem cells, including mesenchymal stem cells (MSCs), has been successfully demonstrated using microcarrier-based small bioreactors such as spinner flasks. In this study, we explored a simple alternative for microcarrier-based MSC expansion using conventional shake flasks. This method relies on a new type of shaker with built-in CO2 gas control capability, the New Brunswick™ S41i incubator shaker. The expansion of adipose-derived mesenchymal stem cells (AdMSCs) was compared between shake and spinner flasks containing microcarriers. The AdMSCs were seeded at a density of 3 × 103 cells/cm2 in both setups, each containing 0.5 g of plastic microcarriers and 50 mL of stem cell growth medium. The cell culture experiments were conducted over 12 days with samples collected daily for cell growth, biochemistry, and metabolite analysis. The study revealed that AdMSCs cultured under shake flask conditions achieved excellent growth under 12-day batch-culture conditions. Finally, the AdMSCs expanded using the shake flask method retained high quality stem cell characteristics, as indicated by CD44 and CD90 stem cell marker assays, and the ability of these cells to differentiate into either adipocytes or osteocytes...

Citation:
Siddiquee K, Sha M. Microcarrier-Based Expansion of Adipose-Derived Mesenchymal Stem Cells in Shake Flasks. BioProcess J, 2014; 12(4): 32-38. http://dx.doi.org/10.12665/J124.Sha.

Posted online January 13, 2014.

 
Biosimilars in the Rest of the World: Developments in Lesser-Regulated Countries

by Ronald A. Rader
Volume 12, Issue 4 (Winter 2013/2014)

Biosimilars, and related biopharmaceutical biobetters and biogenerics, are still relatively new, but are already starting to impact worldwide biopharmaceutical markets. Most discussions of biosimilars center on developed regions where markets are mature and manufacturing capabilities allow for the cost-efficient manufacture of these complex molecules. This article covers the development of these products outside the United States (US), European Union (EU), and other developed, generally rather affluent and high-technology economy-based countries. To start, we first offer some definitions...

Citation:
Rader RA. Biosimilars in the Rest of the World: Developments in Lesser-Regulated Countries. BioProcess J, 2014; 12(4): 41-47. http://dx.doi.org/10.12665/J124.Rader.

Posted online January 13, 2014.

 
Log10 Reduction Factors in Viral Clearance Studies

by Horst Ruppach, PhD
Volume 12, Issue 4 (Winter 2013/2014)

Viral clearance studies are required for pharmaceuticals derived from human and/or animal sources such as recombinant proteins produced in eukaryotic cell lines, human blood products and vaccines, and even for some critical class III medical devices. It is mandatory to demonstrate that steps in the manufacturing process are capable of inactivating or removing potential viral contaminants. For this, a laboratory-scale (downscale) of the process step is developed and challenged with different model virus solutions. The viral concentrations are quantitatively determined in the feed material and the relevant product fraction. The ratio of both defines the reduction in virus and specifies the viral inactivation or viral removal capacity of the investigated process step.

In general, cell line-based infectivity assays like the plaque forming units (PFU) assay or the tissue culture infective dose (TCID50) assay are used to quantify the virus infectivity in the process solutions of a viral clearance study. In some cases, the quantitative polymerase chain reaction (qPCR) may be used. The viral titer derived from the viral infectivity assays is represented by log10/mL values. For instance, viral stock solutions used to challenge a process step typically have a viral titer of >107 log10 PFU/mL or TCID50/mL. The calculated ratio of the viral titer in the starting material and in the relevant product fraction defines the viral reduction, called log10 reduction factor (LRF), log10 reduction value(LRV), or sometimes simply log10 clearance. The mode of the LRF calculation is outlined in the relevant guidelines for viral clearance studies. If possible, the 95% confidence limit is calculated based on the 95% confidence limits of the single viral titers (the 95% confidence interval of the viral infectivity in: [A] the starting material; and [B] the final product fraction using the formula √ a2+b2 )...

Citation:
Ruppach H. Log10 Reduction Factors in Viral Clearance Studies. BioProcess J, 2014; 12(4): 24-30. http://dx.doi.org/10.12665/J124.Ruppach.

Posted online January 7, 2014.

 
Fetal Bovine Serum: The Impact of Geography

by William Siegel and Leland Foster, PhD
Volume 12, Issue 3 (Fall 2013)

Misunderstandings persist regarding geographic origin when sourcing fetal bovine serum (FBS), particularly as it affects quality and cost. This brief communication provides an overview of FBS and sourcing considerations, and direction to resources for further research on related questions. A key concept in evaluating quality in animal-derived raw material is that it is impossible to fundamentally improve the quality by means of any processing. Quality must begin at the source. The importance of geographic origin in suitability assessment is too often overlooked. Global geographic incidence of bovine disease or adventitious agents presents an opportunity for risk management by selecting material from geographic areas with the most limited disease/agent profiles...

Citation:
Siegel W, Foster L. Fetal Bovine Serum: The Impact of Geography. BioProcess J, 2013; 12(3): 28-30.
http://dx.doi.org/10.12665/J123.Siegel.

Posted online September 30, 2013.

 
Improved Production of Laccase and Peroxidase-Free Tyrosinase in Streptomyces antibioticus

by Krothapalli Raja Surya Sambasiva Rao, Niraj Kant Tripathy, Yadla Mahalaxmi, Reddy Shetty Prakasham, and Devarakonda Srinivasa Rao
Volume 12, Issue 3 (Fall 2013)

The impact of individual and interactive behaviors of various fermentation process parameters on laccase and peroxidase-free tyrosinase production were investigated by isolated Streptomyces antibioticus RSP-T1. Six key bioprocess factors (medium pH, rpm, incubation time, sodium chloride concentration, complex nitrogen [yeast extract + peptone], and carbon source [maltose]) were selected based on using a one variable at a time methodology. All selected parameters had an impact at individual and interactive levels on tyrosinase production. Only 25% of the improved tyrosinase production was attributed to the optimized fermentation parameters selected. Regarding the nutritional parameters, the complex nitrogen/carbon source concentration (maltose and yeast extract + peptone) was found to have the most significance impact on overall tyrosinase enzyme production. Physiological growth factors (pH, rpm, and incubation time) played key roles at an interactive level. A maximum yield of 12.60 IU/mL tyrosinase production was achieved with optimized medium, adjusted to 7.5 pH, consisting of 0.75% maltose (w/v), 0.2% yeast extract (w/v), 0.2% peptone (w/v), and 1.25% sodium chloride (w/v) at 160 rpm in 24 hours. This study identified the optimum medium component concentrations for improved tyrosinase production by S. antibioticus RSP-T1. This strain requires complex nitrogen sources (yeast extract and peptone) for increased product yield. Overall, a greater than 250% increase in tyrosinase production was achieved using this optimization approach, as compared to conventional methods...

Citation:
Rao KRSS, Tripathy NK, Mahalaxmi Y, Prakasham RS, Rao DS. Improved Production of Laccase and Peroxidase-Free Tyrosinase in Streptomyces antibioticus. BioProcess J, 2013; 12(3): 46-54.
http://dx.doi.org/10.12665/J123.RaoPrakasham.

Posted online September 30, 2013.

 
Expediting Clinical Batch Production of Viral-Vectored Vaccines and Gene Therapy Products

by Priyabrata Pattnaik, PhD and George Adams
Volume 12, Issue 3 (Fall 2013)

There are approximately 400 vaccines in commercial manufacture targeted at 24 infectious diseases. Of these vaccines, about 300 are viral-based. It is estimated that 1400 vaccines are in development, half of which are viral-based (~ 640 viral vaccines, ~ 200 viral vectors, ~ 60 virus-like particles). Another 240 gene therapy products are in development that utilize the same viral-based technology. A live vector vaccine is one that uses a weakened or harmless microorganism to transport antigenic viral pieces into a cell in order to stimulate an immune response. Vectored vaccines show promise in reliably inducing potent cell-mediated immunity, which is essential for complex diseases such as AIDS, malaria, and cancer...

Citation:
Pattnaik P, Adams G. Expediting Clinical Batch Production of Viral-Vectored Vaccines and Gene Therapy Products. BioProcess J, 2013; 12(3): 41-45.
http://dx.doi.org/10.12665/J123.Pattnaik.

Posted online September 30, 2013.

 
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