A rapid increase in the number of gene therapy trials and products has led to a comparable increase in the need for industrial production of viral gene therapy vectors such as lentiviral, adeno-associated, and adenoviral vectors. Current production systems are limited with respect to scalability and robustness. With our CAP® and CAP-T™ cell lines, we have developed a novel system for high-density suspension culture, efficient and reproducible transfection, and highly efficient production of viral vectors. By upstream process optimization, we have obtained a robust and high-density fed-batch culture system which can be scaled in any current bioreactor format. A design-of-experiments approach has been employed to optimize transient production of lentiviral vectors with significantly higher titers than can be obtained with adherent HEK293T cells…
Category: <span>Biologics Production</span>
The treatment of animal serum by gamma irradiation is performed to mitigate the risk of introducing undesired microorganisms (viruses, mollicutes, or other microbes) into a cell culture. Serum manufacturers and end-users utilize irradiation contractors to perform this process. The irradiation process must be validated, which involves establishing the: (A) minimum dose that achieves the required inactivation of the microorganisms of interest; (B) maximum acceptable dose at which the serum still maintains all of its required functional specifications; and (C) process used by the contract irradiator that allows treatment of the serum product within these defined limits. In the present article, we describe the best practices for qualifying the distribution and magnitude of absorbed dose (performance qualification [PQ] dose-mapping) when serum is gamma irradiated. PQ dose-mapping includes the following: (1) documentation of dose distribution characteristics in defined product load configurations for a specified pathway through the irradiator; (2) assessment of the process capability of the defined product load configurations and irradiation pathway for respecting the dose specification for the serum; and (3) development of a method for routine dose monitoring of the irradiation process with the defined product load configurations and the specified irradiation pathway…
Filamentous fungi are an important class of organisms with significant commercial importance in the biotechnology sector. Those that dominate the markets and are deemed the most important include: Aspergillus, Penicillium, and Trichoderma. They have become indispensable for the production of enzymes due to their exceptionally high capacity to express and secrete proteins. In addition, recent advancements in genomics have allowed for the sequencing or partial sequencing of many of these species. The significance of these fungi and their associated enzymes has accelerated interest in understanding the mechanisms involved in the regulation of gene expression, primarily through the characterisation of the transcriptional elements involved…
In general, yeasts offer advantages for recombinant protein expression because their intracellular environment is suitable for the correct folding of recombinant proteins and grow very high cell densities in defined fermentation media. Within the yeast kingdom, Pichia pastoris has been successfully used for expressing several recombinant proteins. The genome of this yeast contains two copies of the alcohol oxidase (AOX) gene, where the AOX1 promoter regulates 85% of the alcohol oxidase activity and drives the recombinant protein expression into the cell. One of the most successfully recombinant proteins expressed in Pichia pastoris is the hepatitis B surface antigen (HBsAg). The current manufacturing process of the active pharmaceutical ingredient (HBsAg) of the Cuban hepatitis B vaccine (HeberBiovac™ HB) starts with the expression of the HBsAg in Pichia pastoris….
The success of tissue-engineered cartilage constructs (TECCs) as treatment options for healing cartilage defects can only be achieved if suitable preservation methods are found that can maintain their viability and function. Simply lowering the temperature of cells and tissues to below their freezing point invariably destroys them due to ice crystals that form in the water-laden cells and tissues. In addition, high salt concentrations that result from removal of water due to ice formation create a toxic imbalance. If the formation of ice crystals can be minimized while still halting metabolic activity of cells at low temperatures, then the viability and functionality of the preserved tissue may be maintained…
Viable cell density (VCD), the quantitative assessment of living cells, is commonly determined by laborious and inaccurate off-line cell counting methods. Single-function in situ probes have been developed using various technologies including optical density, radio frequency and dielectric permittivity. Optical density measurements predict total biomass but are sensitive to cell debris accumulation and inherent media turbidity. Near-infrared (NIR) has the advantage of being able to measure many key analytes in the cell culture simultaneously. NIR has been used to acquire real-time measurements of glucose, glutamine, glutamate, and media nutrients such as amino acids and metabolites (e.g., lactate and ammonia). NIR probes can be sterilized in place, and real-time measurements can be acquired throughout the mammalian cell culture processes…
The lotus (Nelumbo nucifera) is a fresh-water plant that grows in semitropical climates. It is cultivated extensively in Asian countries, particularly in China. Besides its popularity as an ornamental flower, it is also used as an herbal medicine, mainly in China, Japan, and India, and it displays strong antipyretic, cooling, astringent, and demulcent properties. Lotus seed is widely used as a food in China. Lotus seed is rich in protein, amino acids, unsaturated fatty acids, and has adequate amounts of essential minerals such as potassium, calcium, magnesium, and iron, without heavy metal contamination. As a protein source, the crude protein of lotus seed is higher than parboiled rice (7.70%) and wheat (8.55%). Unlike legumes, lotus seed possesses adequate sulfuric amino acids (methionine + cysteine), comparable to the FAO/WHO and soybean reference patterns. The high content and high quality of protein in lotus seeds emphasizes their value as a vital source of nutrients…
Heterologous expression of membrane proteins remains a bottleneck for structural characterization by x-ray crystallography. Such proteins represent approximately 30% of the proteome and are not sufficiently represented in the Protein Data Bank (PDB). G-protein-coupled receptors (GPCRs) are an area of particular interest as it is estimated that one third of current FDA approved drugs act through this class of receptors. We have been studying rhodopsin with an interest in determining the conformational change that leads to signal transduction in this class of receptors. Although there has been some success in expressing select members of the large GPCR family in bacterial systems, the best characterized expression systems have generally been in mammalian tissue culture…
Many laboratories have utilized cell-free systems or prokaryotic systems designed to produce biological molecules with single polypeptide chains, limited folding requirements, and without glycosylation. The yeast systems are used to generate glycoproteins; however, their glycosylation profiles are vastly different from those of mammalian cells. Without significant glycoengineering, the yeast-produced recombinant glycoproteins may be unsuitable as therapeutic molecules. As such, the use of mammalian cells is still the preferred method to produce complex biological molecules…