During the 1990’s, Bavarian Nordic developed an MVA technology platform (MVA-BN®) based on a novel MVA virus strain. This strain has since been under development by Bavarian Nordic as both a safe smallpox vaccine (IMVAMUNE®) and as the platform vector technology in the company’s vaccine programmes against HIV, Dengue fever, Japanese encephalitis and cancer.
Bavarian Nordic’s research has shown MVA-BN® to have a far superior safety profile compared to other MVA strains in terms of its lack of ability to replicate in vivo. The company has demonstrated that precursor and many other MVA strains replicate in mammalian cell lines. MVA-BN®, the most attenuated MVA strain, does not replicate in monkey (CV-1), rabbit (RK-13), murine (AG-101) and human cell lines (e.g. 143B, HeLa, HaCat and 293), whereas MVA-Vero, MVAI721 and even MVA-571 (which was used in Germany during the smallpox eradication programme) showed a significantly lower degree of attenuation in these cell lines.
The replication of all other MVA strains in mammalian cell lines raises concerns regarding their safety, particularly if they were to be used to vaccinate people who are immune-compromised.
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