Figure 3. Dab2 deficient Treg cells have impaired Gap-junction function.

A. CD4⁺T cells from Ly5.1 congenic mice were co-cultured with Calcein AM-loaded wt or Dab2 CKO CD4⁺CD25⁺ Treg cells and stimulated with plate-bound anti-CD3 plus anti-CD28. The frequency of Calcein⁺Ly5.1⁺ cells at 16 hours of culture was determined. Data are averaged over 3 independent experiments. B. Cytosolic cAMP concentrations in sorted CD4⁺CD25⁺ Treg cells and CD4⁺ CD25^– conventional T cells from wt and Dab2 CKO mice as measured by a standard cAMP ELISA. One of two independent experiments with similar results is shown. C. (Left) Representative flow cytometric plot of intracellular staining of cAMP in ex vivo wt and Dab2 CKO CD4⁺FOXP3⁺ cells. (Right) Mean fluorescence intensity (MFI) of cAMP staining in CD4⁺FOXP3⁺ cells. Data are a mean of 2 independent experiments with at least 6 mice in each group. Error bars are standard error of means. P-values were calculated using Student’s t-test.