Sunday, August 1, 2010

Terminology and their explanations in production and testing and controlling of viral vaccines.

Terminology and their explanations in production and testing and controlling of viral vaccines. 
We will be providing our readers information on virus vaccine production requirements , in our forthcoming series of articles , before that we are providing terminology and their explanation in virus vaccine production requirements.

What is a vaccine :
Vaccine is a biopharmaceutical preparation which up on administered to human or animal subjects is able to stimulate and develop immunity against the particular disease causing organism , may be bacterium , any living cell or a virus.
Vaccine contains completely killed , or partially attenuated microorganism or their protein components like toxins and cell wall proteins , whose virulence is reduced , and which are capable of conferring immunity so that when actually infection occurs body of vaccinated person recognises the infection quickly and produce antigens against the infection, and may prevent or lessen the virulence of infection.

What is viral vaccine
viral vaccines are a heterogeneous class of preventive, and in some cases, therapeutic medicinal products that when administered are intended to elicit immune responses that could prevent and/or lessen the severity of one or more infectious diseases. These products include live attenuated preparations of viruses, inactivated (killed) whole or subunit virions, purified recombinant proteins, synthetic antigens, or live viral vectors expressing specific heterologous vaccine antigens.

ADVENTITIOUS AGENT: A microorganism (including bacteria, fungi, mycoplasma/spiroplasma, mycobacteria, rickettsia, viruses, protozoa, parasites, TSE agent) that is inadvertently introduced into the production of a biological product.

ANCILLARY REAGENT: Reagents that are used in the manufacture or production of a biological product that may or may not end up as part of the final product. Examples include: insulin, transferrin, growth factors, interferon, interleukins, and other proteins, drugs or chemicals like dimethyl sulfoxide.

ANEUPLOID: Having an atypical number of chromosomes which is not an integer multiple of the haploid number.

CELL BANK: Vials of cells of uniform composition (although not necessarily clonal) derived from a single tissue or cell, aliquoted into appropriate storage containers, and stored under appropriate conditions, such as the vapor phase of liquid nitrogen.

CELL LINE (CL): Cells that have been propagated in culture since establishment of a primary culture and survival through crisis and senescence. Such surviving cells are immortal and will not senesce. Diploid cell strains have been established from primary cultures and expanded into cell banks but have not passed through crisis and are not immortal. [The ATCC uses the abbreviation CCL to signify their Certified Cell Lines.]

CHARACTERIZATION: Determination of the properties of a cell substrate or cell bank.

CONTROL CELLS: Cells that are split off from the production culture and maintained in parallel under the same conditions and using the same reagents (e.g., culture medium) in order to perform tests on cells that have not been exposed to the vaccine virus (which may interfere with some tests).

DIPLOID: Having the expected number of chromosomes for a species, (i.e., two of each autosomal chromosome and two sex chromosomes).

ENDOGENOUS VIRUS: A virus whose genome is present in an integrated form in a cell substrate by heredity. Endogenous viral sequences may or may not encode an intact or infectious virus.

END-OF-PRODUCTION CELLS (EOPC): Cells cultured (under conditions comparable to those used in production) from the MCB or WCB to a passage level or population doubling level comparable to or beyond the highest level reached in production.

FINAL BULK: The stage of vaccine production directly prior to filling of individual vials. The final bulk often represents a processed harvest.

FREE OF and FREEDOM FROM: For a substance to be considered free of a contaminant, an assay must demonstrate that a defined quantity of the substance is negative for that contaminant to a defined level of sensitivity. The level of assay sensitivity is defined by the choice of assay and can be determined experimentally using standardized reagents. Alternatively, a validated process that is known to remove a contaminant to a defined level may be used to demonstrate freedom from that contaminant.

HARVEST: At the end of vaccine virus propagation in cell culture, material is collected from which vaccine will be prepared. This material may be the culture supernatant, the cells themselves (often in disrupted form), or some combination thereof.

IMMORTALIZATION: The process by which cells with finite lifespan (e.g., primary cells, diploid cell strains) are converted to those with infinite lifespan.

LATENT VIRUS: A virus that is present in a cell, without evidence of active replication, but with the potential to reactivate, is considered to be microbiologically latent.

MANUFACTURER'S WORKING CELL BANK (MWCB) OR WORKING CELL BANK (WCB): A cell bank derived by propagation of cells from MCB under defined conditions and used to initiate production cell cultures on a lot-by-lot basis.

MASTER CELL BANK (MCB): A bank of a cell substrate from which all subsequent cell banks used for vaccine production will be derived. The MCB represents a characterized collection of cells derived from a single tissue or cell.

MASTER VIRUS SEED (MVS): A viral seed of a selected vaccine virus from which all future vaccine production will be derived, either directly, or via Working Virus Seeds.

ONCOGENICITY: The property of certain biological agents (e.g., viruses) or materials (e.g., nucleic acids) that are capable of immortalizing cells and endowing them with the capacity to form tumors. Oncogenicity is distinct from tumorigenicity (See Tumorigenicity).

PARENTAL VIRUS: A virus that has been manipulated in some manner to generate a viral seed with characteristics needed for production.

PARENT CELL BANK: A few vials consisting of cells from which the Master Cell Bank was derived. Parental Cells may be manipulated to derive a cell substrate with desired characteristics.

PASSAGE LEVEL: The number of times, since establishment from a primary cell culture, a culture has been split or re-seeded.

POPULATION DOUBLING LEVEL: The number of times, since establishment from a defined point in the history of a cell substrate (often the primary cell culture), a culture has doubled in number of cells.

PRIMARY CELLS: Cells placed into culture immediately after an embryo, tissue, or organ is removed from an animal or human and homogenized, minced, or otherwise separated into a suspension of cells.

PURITY: Relative freedom from extraneous matter in the finished product, whether or not harmful to the recipient or deleterious to the product. (21 CFR 600.3(r))

QUALIFICATION: Determination of the suitability of a cell substrate for manufacturing based on its characterization.

TUMORIGENIC: A cell type is tumorigenic if it forms tumors when inoculated into animals (generally a syngeneic, an immunosuppressed allogeneic, or an immunosuppressed xenogeneic host). These tumors may be at the injection site or a different site and may also metastasize to other sites.

NON-TUMORIGENIC: A cell type is non-tumorigenic if it is shown not to form tumors in appropriate animal models.

TUMORIGENICITY: Tumorigenicity is the process by which immortalized cells form tumors when inoculated into animals (see Tumorigenic). Tumorigenicity is distinct from Oncogenicity (See Oncogenicity).

TUMORIGENICITY TESTING: An assay/test that determines whether or not immortalized cells are tumorigenic when injected into animals.

VALIDATION OF ANALYTICAL PROCEDURES: Validation defines the performance characteristics of an analytical procedure, based on the demonstration that the procedure is suitable for its intended purpose or use. Validation is generally performed in accordance with the relevant ICH guidelines.

VALIDATION OF PROCESSES: Process validation is establishing documented evidence that provides a high degree of assurance that a specific process will consistently produce a product meeting its pre-determined specifications and quality characteristics.

VIRAL CLEARANCE: The combination of the physical removal of viral particles and the reduction of viral infectivity through inactivation.

VIRUS PRE-SEED: A few vials consisting of vaccine virus from which the MVS was derived.

VIRUS SEED or VIRAL SEED: A live viral preparation of uniform composition (although not necessarily clonal) derived from a single culture process, aliquoted into appropriate storage containers, and stored under appropriate conditions.

WORKING CELL BANK (WCB): See “Manufacturer’s Working Cell Bank (MWCB)”.

WORKING VIRUS SEED (WVS): A viral seed derived by propagation of virus from the MVS under defined conditions and used to initiate production cell cultures lot-by-lot.

No comments: