An HLA-Transgenic Mouse Model of Type 1 Diabetes That Incorporates the Reduced but Not Abolished Thymic Insulin Expression Seen in Patients

Figure 3

Splenocyte composition, insulitis, and autoreactive CD8 T cell specificities in NOD.β₂.HHD.Ins mice. (a) and (b) Splenocytes from 8-week-old female NOD..HHD (filled circles) and NOD.β₂.HHD.Ins mice (open circles) were analyzed by flow cytometry. Each symbol represents an individual mouse. (c) Female NOD..HHD (filled circles) and NOD.β₂.HHD.Ins mice (open circles) were sacrificed at 4 and 8 weeks of age and insulitis indices were determined as described in Materials and Methods and plotted. Each symbol represents an individual mouse. (Mann-Whitney ). Representative islets from a single NOD.β₂.HHD.Ins mouse are also shown. In these images, beta cells appear dark purple and are denoted by red arrows, while the more lightly stained infiltrating immune cells are marked by black arrows. The number on each image indicates the insulitis score of the islet shown. (d) Islet-infiltrating cells from 8-week-old female NOD.β₂.HHD.Ins mice were tested for reactivity to the indicated HLA-02:01-restricted insulin and IGRP epitopes by IFN-γ ELISPOT. Stimulation index was calculated by dividing the number of spots detected for a given peptide by the number of spots detected with an irrelevant HIV-derived HLA-02:01-binding peptide. A stimulation index greater than 2 was considered a positive response.

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