Table 2.

Distribution of viral M antigen and apoptotic cells in tissues from 4-week-old SPF chickens inoculated intranasally with 10^6.0EID₅₀ of rgDkYK10 or rgDkYK10-B5^a

Strain	Tissue	Detection of AIV matrix antigenb at (h p.i.)				Tissue	Detection of apoptotic cellsc at (h p.i.)
		24	48	60	84		24	48	60	84
rgDkYK10	Lung	−, −, −	+, +, −	+, +, −	+, +, +	Lung	+, +, −	+, +, +	++, +, +	+, ++, ++
	Spleen	−, −, −	+, +, −	+, −, +	+, +, −	Liver	+, +, +	+, +, +	+, +, +	++, ++, +++
	Brain	−, −, −	+, +, −	++, +, ++	+++, +++, +++
rgDkYK10-B5	Lung	−, −, −	+, +++, ++	++, ++, +++		Lung	+, +, +	++, ++, +	+++, +++, +++
	Spleen	−, −, −	+, ++, ++	+, +, +		Liver	+, +, +	++, +++, +++	++, ++, ++
	Brain	−, −, −	++, ++, +	++, ++, ++

^aThree chickens per group were killed at each sampling point (24, 48, 72, and 84 h p.i.). The lungs, spleens, and brains were examined for the virus replication kinetic analysis, and the lungs and livers were tested for the detection of apoptotic cells.

^bAIV matrix antigen was detected by immunohistochemistry. Grading by level of AI virus matrix protein or detected: −, none; +, mild; ++, moderate; +++, severe.

^cApoptotic cells were detected with the ApopTag peroxidase in situ apoptosis detection kit (Chemicon International, Inc.) according to the manufacturer's instructions. Grading by level of apoptotic cells detected: −, none; +, mild; ++, moderate; +++, severe.