FACS analysis of C57BL/6 PECs. (A) Density plot of the forward/side scatter analysis. Three subpopulations (R1, R2, R3) are distinguishable and gated. (B) Histograms of the expression of different surface markers on PECs of region R1 and R2. The black lines give the background fluorescence with the corresponding isotype control antibodies. (C) Two-parameter dot plot analysis of PECs of region R3. The percentages of CD3⁺CD4⁺ and CD3⁺CD8⁺ T cells, NK1.1⁺DX5⁺ NK cells, and CD3⁺NK1.1⁺ NKT cells are given in the plot panels. R3 also contained various myeloid cell types (staining not shown; see the first paragraph of “Multi-color FACS analysis of thioglycolate-elicited PECs and BMMΦ”). The data of Figure 1 are representative for at least 10 independent analyses.