Table 2.

Histopathological changes of chickens after challenge with IBV strains LX4, LHLJ04XI, LHB, LSC99I and LTJ95I.^a

Strain	Group	Days after challenge	Kidneyb	Liverc	Spleend	Proventriculuse	Tracheaf	Lungg
LX4	Vaccineh	6	+i	+	++	+	+	+
		10	−	+	+	−	−	−
	Controlj	6	++	++	++	++	+	++
		10	+	+	−	+	+	++
LHLJ04XI	Vaccine	6	+	+	++	+	−	+
		10	−	+	−	−	−	−
	Control	6	++	++	+	+	+	++
		10	++	+	−	−	+	+
LHB	Vaccine	6	+	+	−	+	++	+
		10	−	+	−	−	+	−
	Control	6	++	++	+	++	++	++
		10	+	+	+	+	++	++
LSC99I	Vaccine	6	+	++	−	+	++	+
		10	+	+	−	−	+	+
	Control	6	++	++	+	++	++	++
		10	+	+	+	+	+	+
LTJ95I	Vaccine	6	++	+	+	++	+	++
		10	+	+	−	+	−	+
	Control	6	+	++	−	+	++	++
		10	+	+	−	+	+	+

^aEach chicken was challenged with 0.2 mL of allantoic fluid containing 10,000 EID₅₀ of IBV strain on day 21 post-immunization.

^bKidney: decreased focal stromal lymphocytes, renal necrosis, glomerular expansion of glomerulus, necrosis of epithelial cells, glomerular necrosis, interstitial nephritis disease and ureteral epithelial vacuolation and degeneration.

^cLiver: fatty degeneration and stromal cell-like lesions.

^dSpleen: proliferation of the red pulp, disorder of the white pulp structure and follicular hyperplasia.

^eProventriculus: mucoderm lobular necrosis and decreased lymphocyte.

^fTrachea: decreased lymphocytes in lamina propria, dropsy of mucous layer, vacuole denature and necrosis and defluvium of epithelium.

^gLung: congestion, serosity exudation, decreased focal lymphocytes (more than three in the bronchial mucous membrane), vacuolation and deformation of bronchioloalveolar (II) and edema in the laminae propria.

^hChickens were immunized with recombinant fowlpox virus (rFPV-IFNγS1) co-expressing the infectious bronchitis virus (IBV) S1 gene and the chicken interferon-γ gene.

ⁱHistopathological changes are expressed as “++++, +++, ++, +” and no changes as “−”.

^jChickens were immunized with PBS.