CR3 (CD11b/CD18), a beta(2) integrin, has a key role in innate antimicrobia
l defenses, as evidenced by the leukocyte adhesion (CD18) deficiency syndro
me in humans and the CD11b knockout mouse. CR3 is a highly versatile patter
n-recognition receptor that activates leukocytes via signaling complexes an
d actin reorganization, mediates phagocytosis, and promotes leukocyte trans
migration. (C) 2000 Editions scientifiques et medicales Elsevier SAS.