1a. Objectives (from AD-416):
The purpose of this collaboration is to construct and test an alphavirus replicon particle vaccine that expresses the E2 regions of three different BVDV strains, one being a BVDV1a, one a BVDV1b, and one a BVDV2a.
1b. Approach (from AD-416):
Construct an alphavirus replicon particle vaccine that expresses the E2 regions of three different BVDV strains, one being a BVDV1a, one a BVDV1b, and one a BVDV2a. This prototype vaccine would be administered to BVDV naïve calves and the immune response evaluated.
3. Progress Report:
One of the methods used for control of bovine viral diarrhea viruses in cattle is the use of vaccination. Currently available commercial vaccines use whole live or whole killed virus. For reasons of safety, economics and production reproducibility it is desirable to make a vaccine that includes one or two viral proteins rather than the whole virus. This type of vaccine is called a subunit vaccine. One way of doing this is to insert the gene(s) that code for viral proteins into a biological system that will make the protein but not yield whole virus. This process is referred as protein expression. In this collaboration, NADC researchers worked with researchers from a biologics company to select the viral gene to be expressed, developed methods to detect and quantitate the expressed protein, and assisted in the design of models for testing the effectiveness of experimental vaccines based on the expressed protein. The biological expression system used was an alphavirus replicon. Vaccine made from replicon particles were administered to BVDV free calves in a prime/boost regimen at two dosage levels. Vaccination resulted in neutralizing antibodies. Vaccination with the higher dosage of vaccine resulted in a reduction in clinical signs of disease in vaccinated cattle compared to non vaccinated cattle. A manuscript detailing this research was published in a peer reviewed journal.