Figure 4.

Insulitis and Diabetes in NOD Mice following Transfer of mRNA-Transfected Cells

Female NOD mice were transferred with 10⁷ NOD CD8 T cells that had been transfected with InsB_15–23/β₂m/CD3-ζ mRNA (Ins; n = 16), IGRP_206–214/β₂m/CD3-ζ mRNA (IGRP; n = 16), or control cells electroporated but without mRNA (Mock; n = 24). The mice were screened weekly for glycosuria and following two consecutive positive readings, diabetes was confirmed by a blood glucose reading of >13.9 mmol/L. (A) Incidence of diabetes is shown with data that were analyzed by log-rank survival statistics, comparing the Ins group with the Mock group (p = 0.031). (B) Insulitis scores either when the mice developed diabetes or for the non-diabetic mice at 35 weeks of age are shown. We examined 80–115 islets from at least three mice in each group. The sections were stained with anti-CD8 (top), anti-CD4 (middle), and anti-B220 for B cells (bottom). Scoring for insulitis was as follows: 0, no insulitis; 1, peri-insulitis; 2, less than 50% infiltration; and 3, more than 50% infiltration. Data were analyzed by the χ² test. (C) Examples of the insulitis are shown, with separate staining for CD8 and CD4 T cells, B cells (B220), and insulin, all stained in red, in a diabetic mouse and a non-diabetic mouse. Magnification is 100×.