Time course of islet infiltration comparing RIP-LCMV-GP C57BL/6 with SV129-crossed mice

Insulitis (%)
Time post–LCMV infection
Day 2+++/−+/−nono00000000
Day 4/5+++/−+/−nono00000000
Day 7+/−+/−+/−+/−+/−+/−+/−+/−nono808018172300
Day 10++/−++/−+/−+/−nono101015184372320
Day 14+++++++/−+/−yesno686151077780
Day 60+++/−yesno810820
  • Groups of 12 RIP-LCMV-GP and RIP-LCMS-GP × SV129 (N8 backcross to the B6 background) were infected with LCMV, and 2 mice were histologically analyzed at the indicated times, as described in research design and methods. At least 15 islets were surveyed per mouse; the percentages of noninfiltrated islets, infiltrated islets, and those with perinsulinitis are shown. Note that protected and diabetic mice only diverge immunopathologically after initiation of the local autoimmune process around day 10 post-LCMV infection, when systemic virus has already been cleared, and that the principal feature in SV129 crosses is that lymphocytes still enter into the islets, but insulinitis remains mild and never fills the whole islet. Values for RIP-LCMV-GP (C57BL/6) are shown in normal type. Values for RIP-LCMV-GP (SV129) are shown in bold. Insulinitis score: none = no lympocytes in or around islets; peri = lympocytes solely around the islets; intra = lympocytes found in the islets but do not fill out the whole islet; full = whole islet appears filled with lympocytes. −, no histological signal detectable; −/+, 8–10 positive cells per islet; +, 20–40 positive cells per islet; ++, too many cells to count.