Presence of bovine spongiform encephalopathy (BSE) in the food chain in Europe, and the reaction of regulatory agencies, has created a unique opportunity for a new microcarrier, one that is itself free of animal proteins but will function under sera-free conditions. Results of Phase I experiments have clearly demonstrated proof of principle for the copolymer trimethylamine (TMA) microcarrier. Cell culture experiments during Phase I included attachment, spreading and growth using MDCK, MDBK, VERO, CEF, human diploid fibroblast cell lines and a cell line not proposed but of commercial interest in gene therapy, COS-7. All the above cell lines (except human diploid fibroblasts) when cultured under sera- free conditions, attached quickly, spread rapidly and were harvested with ease. The overall goals of Phase Il research are aimed at the near term development of this unique microcarrier.
Specific aims of the research proposed include: (l) demonstrate growth of the cell lines at the five liter scale in our bioreactor on TMA microcarriers, (2) assess TMA microcarrier performance by producing vaccine-strain viruses as endpoints (3) identify process engineering variables that determine protein syntheses, (4) assess TMA microcarriers as a support for gene transfection and (5) using TMA microcarriers assess production of extracellular matrix proteins and extracellular matrix-degrading proteolytic enzymes.
Domestically manufactured SoloHill microcarriers have found applications in the U. S. animal health industry. Swedish microcarriers are used in Europe under sera-containing conditions. But commercial producers of human biologicals that use serum may very likely change to sera-free processes, driven largely by the presence of BSE in Europe. Research has shown that this new TMA microcarrier functions very well with low adherent cells under sera-free conditions. TMA microcarriers may expand market usage in (l) large scale cell culture, and perhaps in the latest (2) cell therapy and (3) gene therapy applications currently in Phase I Clinical Trials.
