FIGURE 6. CTLA4 reduction promoted formation of auto antigen-specific CD4⁺ effector memory cells but not effectors.

(A) Purified β-cell auto antigen-specific T_EFF or T_EM cells from the spleen of the BDC2.5/NOD.Foxp3^FIR mice carrying the PL4 vector transgene (GFP⁺) were adoptively transferred into NOD.SCID mice. The animals were monitored for diabetes once every 2–3 days, for 60 days. (B) Representative flow cytometry plots gated on the lymphoid GFP⁺ population (the percentage numbers in plot represent the percentage of the gated population in the total PLN cell population analyzed by flow cytometry), showing the CD4⁺ T_EM and CD4⁺ T_EFF subsets that were adoptively transferred into NOD.SCID mice. (C) Spontaneous diabetes incidence in BDC2.5/NOD mice with or without CTLA4RNAi, or with the PL4 vector control transgene. (D) Flow cytometry analyses of the naïve, T_EFF and T_EM subsets of the conventional CD4⁺ T cell compartment in the PLN and pancreas (numbers represent percentages of gated CD4⁺ T_conv population). (E–F) Frequencies and total cell numbers of auto antigen-specific CD4⁺ T_EM(E) and CD4⁺ T_EFF(F) cells in the ILN, PLN and pancreas. Control data represent a pool of CTLA4RNAi-transgene-negative littermate BDC2.5 mice or age- & sex-matched PL4/BDC2.5 mice (n=7–9 mice per group). Each data-point represents one animal (Mean ± SEM). *p<0.05; **p<0.01; ***p<0.005.