IFN-γ increases efficiency of DNA vaccine in protecting ducks against infection

Table 1 CPE inhibition assay to quantify recombinant DuIFN-γ

IFN-γ(Diluted by log4)	CPE(Four wells)	Averageof CPE	Inhibitionof CPE	Accumulation ofinhibitory CPE	Accumulationof CPE	Inhibitionof CPE	Inhibitionof CPE (%)
1	0, 0, 0, 0	0.00	4.00	27.25	0.00	27.25/27.25	100
2	0, 0, 0, 0	0.00	4.00	23.25	0.00	23.25/23.25	100
3	1, 0, 0, 0	0.25	3.75	19.25	0.25	19.25/19.50	98.7
4	0, 1, 0, 0	0.25	3.75	15.5	0.5	15.50/16.00	96.9
5	1, 0, 1, 0	0.5	3.5	11.75	1.00	11.75/12.75	92.2
6	1, 1, 2, 3	1.75	2.25	8.25	2.75	8.25/11.00	75
7	1, 2, 2, 1	1.5	2.5	6.00	4.25	6.00/10.25	58.5
8	2, 1, 2, 3	2.00	2.00	3.5	6.25	3.50/9.75	35.9
9	3, 3, 3, 2	2.75	1.25	1.5	9.00	1.50/10.50	14.3
10	3, 4, 4, 4	3.75	0.25	0.25	12.75	0.25/13.00	1.9

Table 2 Detection of DuIFN-γ mRNA of PBMCs from ducks after immunization (mean±SD)

Immunized groups	Ratio of DuIFN-γ/IC (weeks after first vaccination)
	1 wk	3 wk	5 wk	7 wk
Group 1 (DHBpreS/S DNA)	1.10±0.06	1.29±0.09ab	1.96±0.17ab	1.26±0.11ab
Group 2
(DHBpreS/S DNA+DuIFN-γ)	1.15±0.08	1.56±0.08b	2.51±0.11b	1.81±0.10b
Group 3 (PBS)	1.04±0.03	0.92±0.06	1.33±0.11	0.94±0.04

^aP<0.05 vs group 2;

^bP<0.01 vs group 3.