TABLE 1.

Replication of rhMPV carrying mutations in the zinc binding motif in cotton rats^e

Mutanta	No. of cotton rats per group	Viral replicationb in:				Lung histologyc	Lung IHCd
		Nasal turbinate		Lung
		% of infected animals	Mean titer log (PFU/g)	% of infected animals	Mean titer log (PFU/g)
rhMPV	5	100	5.68 ± 0.36 A	100	4.25 ± 0.43 A	1.8 A	3.0 A
rhMPV-C7S	5	100	5.31 ± 0.60 A	100	4.14 ± 0.34 A	1.5 A	2.5 A
rhMPV-C15S	5	100	5.56 ± 0.39 A	100	4.08 ± 0.47 A	1.6 A	2.5 A
rhMPV-C21S	5	0	ND	0	ND	0.5 B	0 B
rhMPV-H25L	5	20	2.3	0	ND	0.8 B	0.5 B

^aCotton rats were inoculated intranasally with DMEM or 2 × 10⁵ PFU wild-type rhMPV or rhMPV mutants. At day 4 postimmunization, animals were euthanized for pathology study.

^bFor rhMPV-H25L, 1 out of 5 cotton rats had detectable virus with a titer of 2.3 log PFU/g. ND indicates that infectious virus was not detectable.

^cThe severity of lung histology was scored for each lung tissues. Average score for each group is shown. 0, no change; 1, mild change; 2, moderate change; and 3, severe change.

^dThe amount of hMPV antigen expression in lung was scored. Average score for each group is shown. 0, no antigen; 1, small amount; 2, moderate amount; and 3, large amount.

^eValues within a column followed by different uppercase letters (A and B) are significantly different (P < 0.05).