RRV replication and IEL responses in the small intestine of RRV-infected infant mice.

<p>A, Proportion of intestines containing infectious RRV following inoculation of 5 day-old NOD, BALB/c and C57BL/6 mice. Infectious RRV was detected by 72 h co-culture with MA104 cells followed by EIA. At each day post infection, intestines from 5 to 6 NOD mice were analysed. On days 1, 2, 3, 4, 5, 6 10 and 14 post infection, intestines from 8, 9, 6, 9, 6, 8, 5 and 6 BALB/c mice and 7, 5, 7, 7, 8, 9, 7, and 6 C57BL/6 mice were assayed, respectively. B, Frequency and C, absolute numbers of CD8αβ TCRαβ IEL on day 2 post mock- or RRV infection. To obtain sufficient cells, 4 to 6 separate cell pools were analysed for each inoculum. Each pool was produced from 2 to 5 (NOD), 2 to 3 (BALB/c) or 3 to 5 (C57BL/6) mice. Cell numbers from pools were normalized to represent cells obtained from a single mouse. D, PD-L1 expression by CD8αβ TCRαβ IEL in RRV-infected mice on days 2, 14 and 21 after infection. Data are expressed as the ratio of PD-L1 expression on cells from RRV-infected mice to the mean PD-L1 expression of mock-infected mice. The numbers of mice analysed and usage of cell pools for day 2 studies were as described for B and C. For days 14 and 21 post infection, each data point represents a pool of cells from 2 (NOD), 3 to 4 (BALB/c) or 2 to 3 (C57BL/6) mice. * p<0.05; ** p<0.01; *** p<0.001. Bar = mean.