Chickens immunization and antibody response.

A) SPF chickens immunization schedule. B) Anti-VP2 antibody titers in the sera of the immunized animals. (VP2-BP) sera of the chickens injected with the VP2-based particles; (C+) sera of the chickens injected with the inactivated commercial vaccine; (C-) sera of PBS injected animals. Individual antibody levels at different time points are reported (D20, 34 and 42). The horizontal lines represent the average antibody titers in each group at different time points. Antibody titers values in the sera of all animals at D34 and D42 in VP2-BP and C+ are significantly higher compared to C- (Student’s t-test p < 0.05).