FIG. 1.
CCR5−/− mice are less susceptible to VACV infection. Groups of female mice age 6 to 8 weeks were either mock infected (PBS) or infected with 104, 105, or 106 PFU of VACV by intranasal inoculation. (A) Body weight was measured daily, and values are recorded as the mean percent weight loss at the indicated time point compared to that of uninfected control mice ± standard error. 104 PFU, n = 10; 105 PFU, n = 12 until day 8 and n = 7 thereafter; 106 PFU, n = 12 until day 3 and n = 7 thereafter. CCR5+/+ mock infected, ▴; CCR5+/+ VACV infected, ⧫; CCR5−/− mock infected, •; CCR5−/− VACV infected, ░⃞. (B) Viral titers were measured in lungs, spleens, and brains of CCR5+/+ (▪) and CCR5−/− (
) mice (n = 10) at the indicated times p.i. with 104 PFU of VACV, as described in Materials and Methods.(C) Lungs of mock-infected or VACV-infected (104 PFU) CCR5+/+ and CCR5−/− mice were harvested on day 7 p.i., fixed in 2% paraformaldehyde, and embedded in paraffin, and 6-μm-thick histological sections were prepared and stained with hematoxylin-eosin. The dotted line indicates the lower level of detection for VACV. *, P < 0.05. ND, not detected.