The team created the vaccine using the parasite’s own proteins. One of these proteins, called Neospora caninum cyclophilin (NcCyP), regulates the response of the host immune system that limits the survival of the parasite in the host after infection. The other protein--called NcSRS2-- helps the parasite attach to and invade host cells. The researchers tested three different vaccine cocktails containing these proteins. One group of mice received a formulation of NcCyP. A second group received a formulation of NcSRS2. A third group was immunized with a mix of both proteins. After vaccination, the mice were inoculated with the parasite. The researchers found mice that received the vaccine formulated with NcCyP alone exhibited the highest levels of protection against the disease. On average, only 13 percent of the mice in this group had detectable levels of N. caninum in brain tissue following infection. In contrast, more than 80 percent of the non-vaccinated mice were infected after challenge.
The scientists found that the serum antibody levels against the protein correlated well with the levels of protection. They also observed that the vaccine containing both NcCyP and NcSRS2 was no more effective than the vaccine that just contained NcCyP. However, more work is needed to evaluate the efficacy of these proteins in protecting cattle--the host animal--against the disease.
September 2, 2008
Original web page at Science Daily