RIFT VALLEY FEVER – EXPERIMENTAL VACCINE FORMULATIONS – ADJUVANTS FOR STABILE MODIFIED-LIVE VACCINES AND SUBUNIT VACCINES
Arthropod-Borne Animal Diseases Research
2012 Annual Report
1a.Objectives (from AD-416):
The long term goal of this project is the development of vaccine platform technologies for Rift Valley fever that are suitable for use with multiple novel formulations of attenuated and inactivated or subunit vaccines. The main objectives of this proposal are: (1) To evaluate novel adjuvant formulations that will work with multiple antigen and vaccine delivery formats in cattle and sheep; and (2) To evaluate the ability of these adjuvants to provide thermal stability to the vaccines. Experimental formulations of RVF virus will be screened in mice and successful candidate formulations tested in sheep and cattle. The same successful formulations will be subjected to accelerated and real-time stability studies.
1b.Approach (from AD-416):
The National Veterinary Stockpile Recommendations list Rift Valley Fever (RVF) as the third most important agricultural threat to U.S. livestock. There are multiple vaccine candidates under development and likely more to emerge from basic research. The USDA, ARS, Arthropod-Borne Animal Diseases Research Unit (ABADRU), is involved with multiple research and development projects to select vaccines for eventual field and stockpile use. The RVF vaccines of the future need to be compatible with a Differentiate Infected from Vaccinated Animal (DIVA) control strategies. The ideal vaccine candidate should be safe and inexpensive to produce and use. The ideal vaccine candidate should also be thermostabile providing an extended in-use period where cold storage is not required.
The objective of this cooperative agreement is to develop novel adjuvants for vaccines that can protect sheep and cattle from Rift valley Fever virus infection. We have recently developed an novel adjuvant that can be used in modified live virus vaccine. This adjuvant is not virucidal and animals vaccinated with the adjuvanted vaccine developed earlier and specific cellular and antibody responses to the virus. In addition, the adjuvant suspension has been used to develop monoclonal antibodies for use in diagnostic assays for Rift Valley fever virus. Candidate monoclonal antibodies to Rift Valley fever virus NSs protein have been developed. The specificity of these antibodies will be tested in the near future.