Table 2.

Induction of apoptosis in the spleen following infection with HK/483

VirusaMean no. of TUNEL-positive cells/HPF ± SEb
Day 2Day 3Day 6
X-31ND1.3 ± 0.12.0 ± 0.3
Dk/SingND1.3 ± 0.31.8 ± 0.2
PR/8ND2.0 ± 0.22.4 ± 0.3
HK/4861.2 ± 0.32.5 ± 0.22.1 ± 0.2
HK/4832.1 ± 0.412.6 ± 1.1c 16.8 ± 1.3c
  • a BALB/c mice were i.n. infected with 100 MID50 of HK/483, HK/486, Dk/Sing, or X-31. An additional group was infected with 1,000 MID50 of PR/8 to induce a lethal infection.

  • b Mice were euthanized on the indicated days p.i., and apoptotic cells were identified in histological spleen sections using the TUNEL assay. Two spleens from uninfected mice were included and served as naive controls (mean = 1.8 ± 0.1 TUNEL-positive cells/HPF). The number of TUNEL-positive cells was determined in a coded fashion by visually counting 10 HPF of each stained section. Values represent means ± SE of two to three mice per group.

  • c P < 0.005 compared with HK/486-infected group.