TABLE 4.

Venus stability in Venus-H5N1 viruses in mice^a

Virus	Mouse	No. of plaques examined	No. of Venus-negative plaques
rgMA-Venus-H5N1	1	105	1
	2	109	0
	3	127	0
WT+MA-(PB2+PA)	4	116	6
	5	111	3
	6	115	3
WT-Venus-H5N1	7	145	22
	8	120	18
	9	95	15

^aSix-week-old C57BL/6 mice were infected intranasally with 10⁵ PFU of each virus in a 50-μl volume. Three mice from each group were euthanized on day 4 p.i., and their lung tissues were collected and homogenized in PBS. The supernatants of the lung samples were inoculated into MDCK cells to check for Venus expression, and Venus-negative plaques were picked up and amplified in MDCK cells. Amplified Venus-negative plaques were rechecked for Venus expression to exclude false-negative plaques.