Shedding of the CD11b subunit during PMN transmigration. (A) Binding regions of antibodies against CD11b or CD18. (B) Cleavage of CD11b and CD18 in PMNs migrating across inverted T84 monolayers. (C) Cleavage of CD11b and CD18 in PMNs isolated from human PUS. (D) Partial association of the soluble cleaved CD11b and CD18 fragments in the supernatant of the migrating PMNs. Data represent 3 or more independent experiments.