FIG. 2.

SIRPα-induced NO production by macrophages does not involve blocking of SIRPα-CD47 interactions. (A) Flow cytometric analysis of the binding of beads coated with rat SIRPα-CD4d3 + 4 chimeric protein (or control CD4d3 + 4 beads) to rat peritoneal macrophages or rat thymocytes. Where indicated, cells were preincubated with anti-CD47 MAb OX101 or control IgG1 (MAb OX45) or with anti-SIRPα ED9 Fab fragments or OX41 Fab fragments. (B) NO production by NR8383 cells stimulated with intact ED9 MAb (10 μg/ml) or ED9 Fab fragments (20 μg/ml). Data are expressed as the means ± SD from three independent experiments (*, P < 0.01 by Student's t test).