Engineered Bovine Adenovirus-3 for Oral Vaccination of Calves
Research Lead: Dr. Suresh Tikoo , University of Saskatchewan
Executive Summary
Over the years, use of vaccines (inactivated or live attenuated) produced by conventional ways have raised concerns about their safety, efficacy and virulence. One feasible way is to develop safe, effective and economically viable live-vectored vaccines. As such, attempts are being made to develop and use live viral vectors for the production (cost effective) and safe delivery of viral vaccine antigens. We have choosen to develop bovine adenovirus (BAV)-3 as a vaccine delivery vehicle for cattle. Although BAV-3 vector can efficiently deliver vaccine antigens to respiratory mucosal surfaces of cattle, its potential use in delivering vaccine antigens to enteric mucosal surfaces of cattle has not been successful. One way to increase the utility of BAV-3 vector for delivering vaccine antigens to enteric mucosal surfaces of cattle is by genetic modification of capsid proteins including key mediators of the cell entry process.
The overall objective of the project was to develop and test the genetically modified BAV vectors, which can transduce the enteric mucosal surfaces of cattle. Using genetic modification of the capsid proteins, we have demonstrated the feasibility of constructing viable recombinant BAV expressing chimeric fiber protein or chimeric pIX protein. In addition, we demonstrated that genetic modifcation of capsid proteins alters the tropism of BAV and helps to increase the transduction of enteric mucosal surfaces of cattle. However, further experiments need to be done before full potential of this approach (genetically modified vectors) can be realized.