FIG. 2.

The frequency of IGRP-specific CD8⁺ T-cells is significantly reduced in Idd9 congenic mice. NOD, NOD-Idd9, and B10.D2 10- to 14-week-old female mice were infected with 1 × 10⁷ pfu Vac-IGRP i.p. On day 7 after infection, spleens were analyzed by fluorescence-activated cell sorter (FACS) for CD8⁺ IGRP-tetramer⁺ cells. Pooled results from three experiments are shown; horizontal lines show median value. A: Frequency P < 0.0001 (***) of NOD (5.2%, IQR: 2.4–9.4%) vs. Idd9 (0.5%, IQR 0.4–0.6%) using the Mann-Whitney test. B: Total cell number P < 0.0001 (***) of NOD (1,731 × 10³, IQR 996–2,939) vs. Idd9 (133 × 10³, IQR 103–205) using the Mann-Whitney test. C and D: Islet-infiltrating leukocytes were isolated from the pancreas of NOD and Idd9 10- to 14-week-old female mice (three pooled mice). Pancreas leukocytes and PcLN cells were stained with IGRP-H2K^d tetramer anti-CD8⁺ and propidium iodide. C: Individual FACS plots. D: Collective data from three experiments. Line depicts mean value. PcLN, NOD (0.15 ± 0.04%) vs. Idd9 (0.08 ± 0.03%), P = 0.06; pancreas, NOD (4.8 ± 2.1%) vs. Idd9 (0.4 ± 0.4%), P = 0.0015 (**, mean ± SD, P value calculated using unpaired t test). NS, not significant.