Activated H-Y male CD8^lo cells expressed NK receptors and DAP12 after activation. (A) Lymph node cells from H-Y male and female mice were depleted of CD4⁺Ig⁺ cells and stained with the indicated antibodies. The histograms represent the expression of the indicated cell surface markers by gated female H-Y TCRα⁺ CD8⁺, male H-Y TCRα⁺ CD8⁺, or unstained cells. (B-C) Sorted CD8⁺ H-Y TCRα⁺ male or female cells (1 × 10⁶) were cultured with irradiated B6-Tap^-/- (1 × 10⁷) splenocytes + H-Y peptide (1 μM) and IL-2 (20 U/mL) for 4 days. (B) Histograms represent the expression of the indicated cell surface markers by gated CD8^hi, CD8^lo, or unstained cells on day 4. (C) PCR using primers specific for DAP10, DAP12, or β-actin on cDNA from antigen + IL-2-activated CD8^hi and CD8^lo cells and IL-2-activated B6 NK cells.