Table 1.

Experimental design of the immunization and challenge tests against QX-like IBV strain SD in chickens^a.

Group	No. of chickens	Age (d)	Vaccine	Route	Challenge		Route and dose of challenge
					Day 21	Day 35
A	10	1	Ma5b	Oculo-nasally	IBV strain SD	–	Oculo-nasally, 106 EID50/bird, 0.2 mL
B	10	1	LDT3-Ab	Oculo-nasally	IBV strain SD	–	Oculo-nasally, 106 EID50/bird, 0.2 mL
C	10	1	QXb	Oculo-nasally	IBV strain SD	–	Oculo-nasally, 106 EID50/bird, 0.2 mL
D	10	1	Ma5 + H120c	Oculo-nasally	–	–	Oculo-nasally, 106 EID50/bird, 0.2 mL
E	10	1	LDT3-A + H120c	Oculo-nasally	–	IBV strain SD	Oculo-nasally, 106 EID50/bird, 0.2 mL
F	10	1	QX + H120c	Oculo-nasally	–	IBV strain SD	Oculo-nasally, 106 EID50/bird, 0.2 mL
G	10	1	QX + QXd	Oculo-nasally	–	IBV strain SD	Oculo-nasally, 106 EID50/bird, 0.2 mL
H	10	1	PBS	Oculo-nasally	IBV strain SD	–	Oculo-nasally, 106 EID50/bird, 0.2 mL
I	10	1	PBS + PBS	Oculo-nasally	–	IBV strain SD	Oculo-nasally, 106 EID50/bird, 0.2 mL
J	10	1	–	–	–	–	Oculo-nasally, PBS, 0.2 mL

^aAll chickens are local egg-producing chickens.

^bVaccination at day 1.

^cMa5, LDT3-A or QX vaccination at day 1, H120 vaccination at day 21.

^dFirst vaccination at day 1, second at day 21.