Animal-Derived Raw Materials (Secondary)
Non-animal in origin but may be derived from processes that include materials from animal components that come in direct contact with the raw material, for example, a recombinant protein produced in an E. coli fermentation that uses fermentation medium containing tryptone, or a recombinant protein expressed in plants that are exposed to bovine manure fertilizer. (TR83)
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Animal-Derived Raw Materials (Primary)
Contains in the final raw material or uses in the manufacturing process of the final raw material, any raw material derived directly from bovine or other animal tissues, for example, bovine serum, porcine-derived trypsin, and animal-tissue-derived hydrolysates. (TR83)
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Process Characterization of Viral Clearance
Viral clearance studies in which nonspecific model viruses are used to assess the general virus clearance capacity of the manufacturing process to remove and/or inactivate viruses. (TR41)
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Process Evaluation Studies of Viral Clearance
Viral clearance studies in which relevant and/or specific “model” viruses are used to determine the ability of the manufacturing process to remove and/or inactivate these viruses. (TR41)
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Primer
A short synthetic single-stranded nucleic acid complementary to a specific sequence of a target gene, DNA or RNA. It usually serves to initiate the de novo synthesis of nucleic acid from a template. (TR50)
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Virus Seed
An initial virus stock produced after a new virus is introduced into a laboratory. Its purpose is to create a Master Virus Bank. (MVB) (TR47)
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Virus Production Lot
A virus preparation that is used directly in a clearance study. It can be crude or purified. Typically a large volume is produced, tested and qualified. This volume is divided into multiple aliquots for individual clearance studies. (TR47)
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Volumetric Throughput (Vmax)
The maximum volume that can be processed through a filter area. It is the volumetric capacity of the filter for a given process fluid and generally expressed in L/m2. (TR41) (TR47)
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Virus Removal
Physical separation of virus particles from the intended product. (TR41)
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Working Seed Lot
A seed lot generated from the master seed stock by a single passage. (TR51)
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Virus (Relevant Virus)
A virus used in process evaluation studies that either is the virus, or of the same species as a virus known to or possible to contaminate the cell substrate or any other reagents or materials used in the production process. (TR47)
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Toxicity Studies (also referred to as “Tox” studies)
In vivo or in vitro experiments in which test articles are studied prospectively in test systems under laboratory conditions with the primary goals of identifying the following: 1) an initial safe dose and subsequent dose escalation schemes in humans; 2) potential target organs for toxicity and for the study of whether such toxicity is reversible; and, 3) safety parameters for clinical monitoring after the appropriate dosing and administering schedule is followed (relevant to the drug being studied). In toxicity studies, the test animals are examined by histological or serological methods in order to identify toxic, mutagenic, or teratogenic effects of the drug. It is sometimes possible to collect physiological data from the animals prior to sacrifice. Some toxicity studies may be performed using cell culture methods. Toxicity studies are also described by the U.S. FDA as “nonclinical laboratory studies” and by ICH as “preclinical safety evaluations”.
The definition does not include studies using human subjects or clinical studies, field trials in animals, or any basic exploratory studies carried out to determine whether a test article has any potential utility or to determine physical or chemical characteristics as described in ICH S6 and 21 CFR Part 58 (GLP). (TR56)
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Transmission Electron Microscopy (TEM)
A microscopy technique whereby a beam of electrons is transmitted through an ultra-thin specimen, interacting with the specimen as it passes through it. An image is formed from the electrons transmitted through the specimen, which are magnified and focused by an objective lens, and appear on an imaging screen. (TR41)
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Tissue Culture Infectious Dose – TCID50
The dilution of virus that results in the probability of infection of 50% in replicate tissue-culture inoculations. (TR41)
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Transcription-Mediated Amplification (TMA)
An isothermal NAT method that can amplify RNA or DNA targets a billion-fold in less than one hour. TMA technology uses two primers and two enzymes: RNA polymerase and reverse transcriptase. (TR50)
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Ultrafiltration Membranes
Membranes that retain particles whose sizes are measured by molecular weight, with retention ranges from 1,000 to 1,000,000 (Daltons). (TR41)
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Virus (Non-specific Model Virus)
A virus used for characterization of viral clearance of the process when the purpose is to characterize the capacity of the manufacturing process to remove and/or inactivate viruses in general, i.e., to characterize the robustness of the purification process. (TR47)
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Virus
A simple, potentially pathogenic organism composed of a single type of nucleic acid (DNA or RNA) encased in a protein shell (called a capsid) and, in some cases, a lipid membrane (called an envelope). Viruses are incapable of independent replication and therefore must infect a host cell in order to propagate. (TR41)
Obligate, intercellular, replicating, infectious agents that are potentially pathogenic, possessing only a single type of nucleic acid (either RNA or DNA). They use the host cells for propagation as they are unable to grow independently, for example by binary fission, and multiplying their genomic material. (TR47) (TR83)
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Touchdown PCR
A technique to reduce appearance of non-specific amplicons in PCR reactions. The earliest cycles of a touchdown PCR method have high annealing temperatures. The annealing temperature is decreased in increments for subsequent cycles until a fixed point is reached. (TR50)
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Titer
The concentration of infectious virus calculated, taking into account the dilution factor. (TR41)
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Viral Removal
Physical separation of virus particles from the intended product. (TR47) (TR83)
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Viral Inactivation
Reduction of virus infectivity caused by chemical or physical modification. (TR41) (TR83)
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Virus (Endogenous Virus
Viral entity whose genome is part of the germ line of the species of origin of the cell line and can be produced in culture by cell lines from these species. (TR47)
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TCld50 Assay
Quantal assays for determining the titer of a virus. The 50% tissue culture infective does (TCID50) is the dilution of virus that results in the infection of 50% of cell cultures that have been infected with the same dilution of the virus sample. (TR47)
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Specific Model Virus
Virus that is closely related to the known or suspected virus (same genus or family), having similar physical and chemical properties as those of the observed or suspected virus. (TR41)
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Surrogate Fluid
A model process fluid used in a small-scale validation study. The fluid is intended to either match or resemble an actual process fluid as closely as is feasible. (TR41)
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Stirred-Cell Filtration
A surrogate for tangential flow filtration where shear is achieved by rapidly stirring the solution immediately adjacent to the membrane. Typically the stirring is accomplished by mechanical means, such as through the use of a stir bar or impeller. (TR15)
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Reverse Transcriptase PCR (RT-PCR)
A technique for amplifying a defined segment of a RNA molecule. The RNA is first reverse-transcribed into complementary DNA (cDNA), followed by amplification of the cDNA using PCR. (TR50)
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Reporter Gene
A coding sequence linked to a gene or promoter of interest. It is generally used to determine activation of the promoter or expression of the gene of interest in a cell or organism. (TR50)
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Relevant Virus
A virus used in process evaluation studies that either is the identified virus, or of the same species as the virus known to or likely to contaminate the cell substrate or any other reagents or materials used in the production process. (TR41)
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Pyrogen
Any substance capable of eliciting a febrile (or fever) response upon injection or infection (as in endotoxin released in vivo by Gram-negative bacteria. (TR3) Fever-producing substance (TR69) A material that elicits a pyrogenic response (fever). (TR70)
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Q-PCR Probe
A synthetic, chemically-labeled single-stranded nucleic acid complementary to a selected sequence within a DNA sequence to be amplified using forward and reverse primers in a Q-PCR reaction. A probe is typically labeled with both a fluorophor and quencher. The latter inhibits fluorescence until the quencher and fluorophore are separated by the exonuclease activity of DNA polymerase. (TR50)
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Polymerase Chain Reaction (PCR)
A technique widely used in molecular biology in which a DNA polymerase is used to amplify a piece of DNA by in vitro enzymatic replication. As PCR progresses, the DNA thus generated is itself used as a template for replication. This sets in motion a chain reaction in which the DNA template is exponentially amplified. This technique may be used to quantify virus. (TR41) (TR47)
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Plasmid
An extra-chromosomal DNA molecule in bacteria which is capable of replicating independently of the host chromosomal DNA. Plasmids are often used as positive controls for NAT assays. (TR50)
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Plaque Forming Unit (PFU)
A measure of virus infectively based on formation of a region, or “plaque” of lysed cells within a monolayer culture caused by viruses that kill and disrupt their host cell. The number of plaques is directly correlated to the number of infectious virus particles. (TR47)
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Monodispersed particles
Particles of uniform size in a dispersed phase. In the case of viruses, this term refers to free virus particles not agglomerated to other viruses or proteins in solution. (TR41)
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Nonspecific Model Virus
A virus used for characterization of viral clearance of the process when the purpose is to characterize the capacity of the manufacturing process to remove and/or inactivate viruses in general (i.e., to characterize the general viral clearance capacity of the purification process.) (TR41)
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Nominal Molecular-Weight Cutoff (NMWCO)
A manufacturer’s measure of an ultrafiltration membrane based on a defined solute-retention coefficient. (TR15)
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Nucleic Acid Sequence Based Amplification (NASBA)
An isothermal amplification method targeting RNA in which amplifications of RNA occurs via DNA intermediates. Each of the DNA templates can make 100 to 1000 copies of RNA amplicons, potentially resulting in the production of greater than a billion amplicons. (TR50)
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Most Probable Number (MPN) Method
A statistical method of estimating the number of viable organisms suspended in a liquid. (TR51)
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Nucleic Acid Standard
A sample with a precisely measured content of specific nucleic acid. A nucleic acid standard can be serially diluted to assess the limit of detection of an NAT assay or to create a standard curve for Q-PCR to determine the concentration of target nucleic acid. (TR50)
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Nominal Pore Size Rating
A filter rating with an arbitrary value, indicating a particulate size range at which the filter manufacturer claims the filter removes some percentage. Nominal ratings vary from manufacturer to manufacturer and may not be suitable to compare filters among manufacturers. Processing conditions, such as operating pressure and concentration of contaminant may have a significant effect on the retention efficiency of the nominally rated filters. (TR41)
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Limiting Dilution
In the context of this Technical Report the limiting dilution technique is used for virus cloning. The virus suspension is diluted until virus is no longer detectable. The dilution immediately before the dilution where infection of cells is no longer detectable is considered to contain only one virus particle or a very low number of virus particles. (TR47)
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Matrix Spike Control
An internal control in which an amplifiable amount of nucleic acid is added to a test article to determine inhibition of the PCR. This addition is usually performed pre-extraction and should provide a weak signal 100% of the time. Also known as “interference control”. (TR50)
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Melting Temperature (Tm)
The calculated or observed temperature for a primer/nucleic acid mixture at which 50% of primer-binding sites are in single strand form. (TR50)
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Master Cell Bank (mCb)/Master Virus Bank (mVb)
A stock of cells or virus used to produce the Working Cell Bank or the Working Virus Bank. Cell/virus banking is used to enhance biological consistency. (TR47)
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Log Reduction
Log reduction is defined as the first log being 90%, the second log being 9% and the third log being 0.09% of the original inoculums. (TR70)
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Media
The part of the filter through which fluid passes that retains particles during filtration. (TR45)
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Latent Virus
Latency is the ability of a virus to be dormant (latent) within a cell (for example, genetic episomes; provirus). Under certain conditions the virus may become active and produce particles. (TR71)
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Lenticular Filters
A filter made up of a series of biconvex cells that are stacked on top of one another with rings between them to prevent bypass between the cells. End-caps are then placed at the top and bottom of the assembly and are held in place with a central core. [Synonyms: Lenticular Cartridge, Modules, Filter Elements, Filter Devices] (TR45)
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