mNK cells do not acquire B220 expression in vivo. (A) Gating strategy used to sort mNK-cell subsets from the spleen of B6.SJL mice. Sorted cells are CD3⁻ CD19⁻ CD11c^−/low B220⁻ CD49b⁺ and either CD27⁺ or CD27⁻. Cell purity was routinely > 93% for each cell type. (B-E) The CD27⁺ and CD27⁻ mNK-cell subsets sorted from the spleen of B6.SJL (CD45.1) mice were adoptively transferred into (B-C) C57BL/6 (CD45.2) mice or (D-E) B6.Rag1^−/− (CD45.2) through tail vein injections. The spleen cells were analyzed (B,D) 5 and (C,E) 15 days after transfer. The expression of CD11b, CD27, CD49b, CD43, CD11c, and B220 on CD45.1⁺ CD45.2⁻ transferred cells is shown. Bold histograms represent the level of expression of CD49b or CD43 marker on the indicated cell population. Shaded histograms represent the expression level of CD49b on host B cells (B-C) or on host dendritic cells (D-E). Shaded histograms represent the expression level of CD43 on host B cells (B-C) or on host CD11c^lowB220⁺CD11b⁻ (D-E). Results are representative of ≥ 3 independent experiments.