|Fowler, Veronica - INST. ANIMAL HEALTH, UK|
|Paton, David - INST. ANIMAL HEALTH, UK|
|Barnett, Paul - INST. ANIMAL HEALTH, UK|
Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 4, 2008
Publication Date: February 22, 2008
Citation: Fowler, V.L., Paton, D.J., Rieder, A.E., Barnett, P.V. 2008. Chimeric Foot-and-Mouth Disease Viruses: Evaluation of Their Efficacy as Potential Marker Vaccines in Cattle. Vaccine. 26:1982-1989. Interpretive Summary: The main purpose of this work was to assess the ability of intertypic Foot-and-Mouth Disease Virus (FMDV) vaccines produced and characterized originally at Plum Island, to protect the major target species, cattle, and to assess whether these chimeric constructs can be used as effective marker vaccines. In the previous study conducted at Plum Island (Rieder, et al, 1994) demonstrated that it was possible to produce a stable, fully infectious FMDV chimeric virus containing the VP1 G-H loop of another major FMDV serotype. Swine inoculated with this chimeric vaccine demonstrated neutralizing antibodies to both serotypes, which conferred protective immunity to the backbone serotype and partial protection against the inserted VP1 G-H loop serotype. In the current study all vaccinated cattle challenged at day 21 with wild type virus were fully protected, further suggesting that perhaps a response towards the VP1 G-H loop is not essential for protective immunity in cattle. In addition, two novel assays were developed for use with the chimera vaccine constructs and the results compared favorable to other standardized tests that target the response to FMDV non-structural proteins.
Technical Abstract: Previous work in swine has demonstrated that full protection against Foot-and-Mouth Disease (FMD) can be achieved following vaccination with chimeric Foot-and-Mouth Disease Virus (FMDV) vaccines, whereby the VP1 G-H loop has been substituted with a non-homologous alternative. If proven to be effective in other economically important species such as bovine, such vaccine constructs could be trialed as potential marker vaccines. Here, we determine if 10 chimeric FMDV vaccines can protect cattle from virus challenge and ii) whether the serological profiles generated from these vaccine constructs can be exploited to identify infection, regardless of vaccination status. Inactivated, oil adjuvanted, chimeric vaccine constructs based on the backbone sequence of the A12 119 serotype virus, fully protected cattle from intradermolingual needle challenge (10 5 TCID 50 cattle adapted A12 119) 21 days post vaccination. Differentiation assays developed for use in this study were able to identify sub-clinical infection which in one vaccinated animal, persisted beyond day 32 post-challenge. This paper emphasizes the importance of epitopes outside of the VP1 G-H loop for protective immunity in cattle, and demonstrates that chimeric FMDV vaccines could prove to be useful marker vaccines for the future.