Figure 4.

Resident CD8⁺ T cells support maintenance of Treg cells in the skin through B7.2/receptor axis. A) Expression of MHCII, B7.1 and B7.2 on skin CD8⁺ T cells. One representative of 4 analyses of 2 experiments. B) Expression of CD28 and CTLA-4 on skin and splenic Treg and CD4⁺ Teff cells. Representative of 4 analyses. C) FC analysis of survival of WT Treg and Foxp3⁻ CD4⁺ Teff cells 1 day after co-culture with WT CD8⁺ T cells in presence of anti-B7.2 or isotype control antibodies. Bar graphs show percentages of live Annexin V⁻ RFP⁺ Treg and Annexin V⁻ Teff cells. N=6 pooled of 2 experiments. D) Survival of WT Treg and Foxp3⁻ CD4⁺ Teff cells 1 day after co-culture with WT or B7.1^−/−B7.2^−/− CD8⁺ T cells, performed same as in (C). N=4 pooled of 2 experiments. E–G) Percentages of Treg cells (E), IL-17⁺ and IFNγ⁺ CD4⁺ cells (F) and CD8⁺ cells (G) in the skin of Rag1^−/− mice 1 month after they are transferred with WT or B7.2^−/−B7.1^−/− CD8⁺ and WT CD4⁺ T cells. N=5 pooled of 2 experiments. H) Analysis of WT and B7.2^−/− donor OT-I cells and host Treg cells in the torso skin of WT recipients 1 week and 1 month after Ova immunization on ears. N=3 each.