Inhibitory MHC-I receptors are preferentially expressed on CD8αα TCR-αβ iIELs. (A) Analysis of NK-cell receptor expression by iIELs and spleen NK cells from B6 mice. iIELs were subdivided into the following groups: (top) ■, TCR-αβ CD8αα; , TCR-αβ CD8αβ; and □, TCR-αβ CD4; and (middle) ■, TCR-γδ CD8αα; and □, TCR-γδ CD8⁻ CD4⁻ (DN). The bar graph represents the mean percentage (± SEM) of cells expressing the indicated NK-cell receptor by the indicated iIEL subset (n = 3-10) or by splenic NK cells (CD3⁻NK1.1⁺; n = 4-9; bottom) in B6 mice. (B) Representative analysis of Ly49A, Ly49G2, and NKG2A/C/E coexpression by CD8αα iIELs (CD4⁻CD8β ⁻CD8α⁺; top) and spleen NK cells (CD3⁻NK1.1⁺; bottom). Numbers indicate the percentage of cells expressing or coexpressing the specific MHC-I receptor(s). Numbers in parentheses represent the frequency of cells coexpressing 2 MHC-I receptors as predicted by the product rule.