CHE and Alk induce degranulation in human neutrophils. PMNs were incubated in the presence (+) or absence of fMLP, CHE or Alk and the release of subset types of granules was evaluated by flow cytometry by monitoring cell surface expression of CD35 (A), CD66b (B) or CD63 (C), as described in Methods. Results are means ± SEM (n = 4). In panel D, supernatants from PMNs incubated with buffer (Ctrl), LPS, CHE, CHE + LPS, Alk, or Alk + LPS were collected and tested by zymography in order to determine whether an enzymatic activity is present, as described in Methods. Results are from one representative experiment out of four.