Figure 6. An autoantigen-specific CD4⁺ T cell which accumulates in the islet but does not cause destruction, does not accumulate in higher numbers in the presence of a diabetogenic CD4⁺ T cell or T cells from whole NOD splenocytes.

Retrogenic mice, with diabetogenic 4.1 T cells labeled with YFP and 12-4.4^V1 insulin-specific T cells labeled with GFP, were analyzed 4.5–6.5 weeks post-transplant. (A) Representative flow cytometric dot plots from B, showing 4.1 (YFP) and 12-4.4^V1 (GFP) T cells in the spleen and pancreatic islets. Plots are gated on live cells and CD4⁺ cells. (B) Top panels; percentage of stem cells for each T cell in the bone marrow (n=7–8), as measured by percentage GFP/YFP expression on Lineage⁻Sca-1⁺c-kit⁺ cells and total numbers of T cells in the spleen. Next three panels, show numbers and ratio to the numbers in the spleen for the pancreatic islets (ISLETS), inguinal lymph nodes (I.L.N.) and pancreatic lymph nodes (P.L.N.), respectively (n=6–9). All Figures show mean (±SEM) and numbers were calculated from cell counts and the percentage CD4⁺FP⁺ live cells. (C) Diabetes incidence. (D) Representative flow cytometric dot plots from E, showing analysis of T cells from 12-4.4^V1 Insulin-specific mice, injected with 10×10⁶ whole splenocytes from 13 week-old NOD mice, two weeks after bone marrow engraftment, and analyzed 4.5–6.5 weeks post-transplant. Plots are gated on live cells and CD4⁺ cells. (E) Left panels; percentage of stem cells for each T cell in the bone marrow (n=7–10), as measured by percentage GFP expression on Lineage⁻Sca-1⁺c-kit⁺ cells and total numbers of T cells in the spleen. Right panels show the numbers and ratio to the numbers in the spleen for the pancreatic islets (ISLETS) and pancreatic lymph nodes (P.L.N.), respectively (n=5–9). All figures show mean (±SEM) and numbers were calculated from cell counts and the percentage CD4⁺GFP⁺Vβ⁺ live cells for the retrogenic T cells and the percentage CD4⁺GFP⁻TCR⁺ live cells for the NOD T cells.