Figure 50.

Gating strategy to identify murine Tr1 cells in the small intestine. A representative gating strategy is shown (A). The dump channel allows exclusion of the majority of myeloid cells (CD11c, CD11b, MHCII), NK cells (NK1.1), gd T cells (gd TCR), CD8⁺ T cells (CD8), B cells (CD19), and – importantly - platelets (CD41), which might stick to CD4⁺ T cells. Stringent gating for CD4⁺ T cells is crucial, since LAG-3 and CD49b not only identify Tr1 cells within the CD4⁺ T cell subset, but also enrich for IL-10-expressing cells within other cell types. Tr1 cells co-expressing LAG-3, CD49b, and IL-10 can be gated according to the strategy shown or alternatively, cells can be first gated for LAG-3⁺ CD49b⁺ followed by gating for IL-10⁺ cells.