Efficient self-assembly and protective efficacy of infectious bursal disease virus-like particles by a recombinant baculovirus co-expressing precursor polyprotein and VP4

Table 2 Protective efficacy of recombinant VLP vaccine against challenge with vvIBDV in 3-week-old SPF chickens compared with a commercial inactivated vaccine or no vaccine (PBS treatment). Two weeks after immunization, birds were challenged with vvIBDV LC10 strain orally (10^4.5EID₅₀ per bird) and observed for 10 days

Vaccine	Mortality, n (%)	Clinical signs, n^a	Gross lesions, n^b	Bursal atrophy, n^c	B/BW ratio, mean (SD)
Inactivated vaccine (n = 12)	0 (0)^**	0^***	3^**	3^**	3.46 (1.42)*
VLP vaccine (n = 12)	0 (0)^**	0^***	4^*	3^**	3.69 (1.74)**
Control (n = 12)	7 (58)	12	5	5	1.14 (0.30)

^aNumber of birds with clinical signs, including depression, anorexia, diarrhea, and death
^bNumber of surviving birds with gross lesions in the BF
^cNumber of surviving animals with a B/BW ratio (bursal weight/body weight x 1000) lower than 2
*P < 0.1, ** P <0.01, *** P <0.001 compared with the non-vaccinated control group (Fisher’s exact test)

ISSN: 1743-422X