The β2 integrin CR3 (CD11b/CD18) does not affect surface expression of FcRI in transgenic mice. (A) Detection of FcRI and CR3 in genomic DNA from wild-type and CR3-deficient mice by PCR. Wild-type CR3 (lanes 1) is marked by the closed arrowhead and mutant CR3 (lane 2) by the open arrowhead. (B and C) Flow cytometric analyses of hFcRI and CR3 expression on peripheral blood granulocytes of Tg,CR3⌈+/− (bold lines), Tg,CR3−/− (thin lines), or NTg,CR3⌈+/− (filled area) mice. Cells were stained with A77-FITC to detect hFcRI (B) or M1/70-FITC to assess CR3 expression (C). Experiments were repeated four times, yielding identical results.