FIG. 5.

Immunohistochemical determination of autoimmune diabetes in APNG^−/− mice 8 months after treatment with STZ. (A and B) Formalin-fixed sections from untreated (A) and STZ-treated (B) APNG^−/− mice were stained for insulin as described in Materials and Methods. (C to F) CD4⁺ and CD8⁺ immunostaining was carried out on frozen sections. Hematoxylin-eosin (C) and insulin (D) staining indicate the position of the islet in the section, while staining for the specific lymphocyte markers shows evidence of CD4⁺ (E) but not CD8⁺ (F) lymphocytic invasion in the islet. The more porous nature of the frozen sections compared to the formalin-fixed sections made them unsuitable for quantitative assessment of insulin content by this method. Arrows indicate the position of the islet in the section. Bar, 100 μm.