IL-2 Mediates CD4+ T Cell Help in the Breakdown of Memory-Like CD8+ T Cell Tolerance under Lymphopenic Conditions
Figure 4
Anti-IL-2 treatment prevents the differentiation of memory-like Clone 4 CD8+ T cells into effectors in response to self-antigen cross-presentation.
Irradiated InsHA mice were either injected with 5×106 CFSE-labeled naïve HNT Thy1.1+ CD4+ T cells or PBS. On day 12, both groups of mice were “refilled” with 100×106 spleen and LN cells from unmanipulated InsHA mice. Four days later, the “refilled” InsHA mice received enriched CFSE-labeled memory-like Clone 4 Thy1.1+ CD8+ T cells, generated by injection of naïve cells into irradiated BALB/c mice 16 days previously. Mice adoptively transferred with HNT CD4+ T cells were also treated with either anti-CD40L, anti-IL-2 or the respective isotype matched control antibodies. Five days after secondary transfer, InsHA mice were sacrificed and donor CD8+ Thy1.1+ lymphocytes from pancreas, LN and pLN were analyzed by FACS. Data from one representative experiment of four are presented. (A) Histograms represent CFSE fluorescence on gated CD8+ Thy1.1+ lymphocytes. The presence of CD8+ Thy1.1+ donor T cells in the pancreas was evaluated by FACS. FACS event counts in the depicted gates are indicated. (B) Graphs represent mean (± SD, n = 3–8 per group) recovered CD8+ donor T cells from the pancreas of mice from indicated groups. (C) Expression of CD25, CD62L and CD44 on gated CD8+ Thy1.1+ lymphocytes of mice treated with anti-IL-2 mAbs was assessed by flow cytometry. Plots represent expression of CD25, CD62L and CD44 as a function of CFSE fluorescence on gated CD8+ Thy1.1+ lymphocytes in the pLN.