Chitosan-coated PLGA nanoparticles as a delivery system for infectious bursal disease viral antigen in chickens.

In the present study, antigen-chitosan-PLGA nanoparticles have been explored as the delivery system for inactivated whole IBD viral antigens. The immunized birds showed the peak antibody level (ELISA titer 4095.65±55.74) at the 3rd week post-immunization, which was significantly higher than that of the commercial inactivated vaccine (titer 2257±30) (P<0.0001). The virus-loaded chitosan-coated PLGA nanoparticles also induced good cell-mediated immunity. The immunized birds also showed better resistance against the challenge infection with a very virulent IBD virus. Only one bird out of the five challenged showed viral antigens in the bursa (80% protection) whereas in commercial vaccinated group 2 chickens showed viral antigen in bursa (60% protection). The histopathological lesions were also found to be very mild in the same group. The chicks, which were immunized with the antigen-chitosan-PLGA nanoparticles, did not show any sign of immunosuppression. It is concluded that antigen-chitosan-PLGA nanoparticles afford the best protection among the groups which lay a foundation for further development of vaccine delivery platform in this line.