Avian cell line - Technology for large scale vaccine production
© Kraus et al; licensee BioMed Central Ltd. 2011
Published: 22 November 2011
The establishment of an immortalized continuous cell line derived from quail cells was undertaken by Baxter in order to develop a new cell line platform for vaccine production that is free of genetically modifying sequences.
Important vaccines and viral vectors are still produced in embryonated chicken eggs or primary chicken embryo fibroblasts. However, the substitution of primary cells by a continuous cell line has several advantages. Although primary avian tissue for virus replication is provided by specific pathogen-free (SPF) production plants, sterility during vaccine production on embryonated eggs is difficult to guarantee, and the constant risk of contamination necessitates the addition of antibiotics. In addition, the supply of embryonated SPF eggs could be a limiting factor in vaccine production if increased amounts are demanded by the vaccine manufacturers, e. g. in case of a pandemic outbreak.
The same is true for approaches where primary fibroblast monolayer cultures are used. Thus, avian cell lines have become a modern option for vaccine manufacturing and will definitely replace egg and primary fibroblast technology.
Cell Line Development and Characterization
Here we describe the development of a continuous avian cell line from quail embryos into serum-free suspension culture and its manufacturing potential for several different vaccines.
Quality control (QC) testing was performed at different stages during cell line development. Extended characterization according to relevant guidelines (Table 1) showed that the cells are free of adventitious agents and F-Pert negative. Tumorigenicity testing performed in BALB/c nude mice indicated no tumorigenic effect. Accordingly, the cells fulfill all the critical regulatory requirements.
List of guidelines according to which the avian cell line was tested
European Directorate for the quality of Medicines & HealthCare
European Pharmacopoeia. (EP) 2.6.16.
Tests for extraneous agents in viral vaccines for human use
Cell substrates for the production of vaccines for human use
The International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH)
Viral safety evaluation of biotechnology products derived from cell lines of human of animal origin
Derivation and characterization of cell substrates used for production of biotechnological/biological products
Good manufacturing practice guide for active pharmaceutical ingredients
Center for Biologics Evaluation & Research (CBER)
Points to Consider in the Characterization of Cell Lines Used to Produce Biologicals (1993)
Guidance for Industry, Characterization and Qualification of Cell Substrates and Other Biological Materials Used in the Production of Viral Vaccines for Infectious Disease Indication (February 2010)
Code of Federal Regulations (CFR)
Detection of extraneous agents viruses by fluorescent antibody technique
General biological products standards
Scalable live virus production in QOR avian cells
For process development purposes, modified vaccinia Ankara (MVA) virus was used as a model virus. MVA virus is a highly attenuated strain of vaccinia virus belonging to the Poxviridae family that was produced by over 500 passages in chicken embryo fibroblasts. MVA has lost about 10 % of the vaccinia dsDNA genome and consequently cannot replicate in primate and human cells. Its complex genome of circa 200 kb allows the insertion of large exogenous DNA inserts. Therefore, MVA serves as a versatile live vector for the development of human vaccines against diverse disease targets, such as malaria and cancer, for which conventional approaches have so far failed .
Furthermore, this avian cell line can serve as a control cell line with different model viruses in QC tests for adventitious agents.
A scalable technology for the production of live and attenuated vaccines based on the qualified avian cell line QOR2/2E11 has been established. The markedly advantages are:
Stable, continuous avian cell line established without the introduction of foreign genes
Post production cells are not tumorigenic in animal model
Suspension growth in low-cost chemically defined medium
TCID50 titers ≥ 1 x 109 for several rMVA constructs tested
This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.