GA (Teva Neuroscience), anti-PIR-A/B (6C1, BD Biosciences) and anti-PIR-B (R&D, Santa Cruz). GA-FITC was synthesized by desalting GA using Zeba columns (Pierce) followed by fluorescein isothiocyanate conjugation (Pierce). PHA, anti-Gr-1, anti-CD115, anti-F4/80, anti-CD11b, and isotype-matched antibodies were purchased from eBioscience. MCA26 (23 (link)) and LLC cells (ATCC # CBL-1642) were subcutaneously (sc) implanted in female BALB/c and C57BL/6 mice, respectively. Wild-type mice were obtained from the Jackson Laboratory (Bar Harbor, ME). Colonies of HA-TCR transgenic (Tg) mice (24 ), and PIR-B deficient mice (22 (link)) were established from the mice generously provided by Drs. C. A. Bona (Icahn School of Medicine at Mount Sinai, New York, NY) and T. Takai (Tohoku University, Japan). Animals were handled in accordance with the institutional animal guidelines.