Figure 2.
Protective viral infection results in increased IP-10 expression in the PDLN and a decrease of islet-infiltrating CD8 lymphocytes. Left: RIP-LCMV-NP mice were infected (inf.) i.p. with 105 PFUs of LCMV-Arm and received a secondary i.p. infection (2nd inf.) after 1 month with 105 PFUs of LCMV-Arm or LCMV-Past. Right: Nine-week-old NOD mice were infected i.p. with 105 PFUs of LCMV-Arm (Arm) or LCMV-Past (Past). (a) Some RIP-LCMV-NP and NOD mice were sacrificed at day 1 after secondary infection for assessment of the expression of IP-10 (CXCR3) in the pancreas and PDLN. The relative IP-10 mRNA expression was analyzed by RNase protection assay and normalized against L32 housekeeping RNA expression (n = 3–4). (b) At day 3 after secondary infection, pancreata and PDLNs were harvested, and 6-μm tissue sections were probed for cellular infiltration by CD4 and CD8 T cells. These representative tissue sections show an average degree of islet infiltration per group as found in the pancreas of individual mice (n = 3–4). (c) Insulitis score as obtained from sections of 3–4 mice per group. Scoring system: 0, no infiltration; 1, some peri-insular infiltration; 2, heavy peri-insular infiltration with some intra-insular infiltrates; 3, heavy intra-insular infiltration and/or islet scars. The mean score was obtained by division of the sum of all individual islet-infiltration scores by the total number of islets analyzed.