Histaminase release from human granulocytes.

Abstract

Histaminase (EC-1.4.3.6), one of the two catabolic enzymes for histamine, is contained in human granulocytes. Opsonized zymosan or the calcium ionophore A-23187 induce a dose-dependent release of histaminase from human granulocytes in vitro. Release is completed within 30 min, is temperature dependent, and requires divalent cations. Opsonized zymosan-induced histaminase release was maximal in the presence of both calcium and magnesium, whereas ionophore release was magnesium independent. The total cellular content of histaminase could be released by both opsonized zymosan and ionophore. In contrast, only 25% of the cellular beta glucuronidase, a lysosomal enzyme, was released after maximal stimulation with opsonized zymosan; there was minimal release of beta glucuronidase with ionophore. Zymosan- and ionophore-induced histaminase release was inhibited by agents that are presumed to interfere with cell metabolism and disrupt microtubules. Human granulocytes therefore may modulate the effect of histamine by releasing histaminase at a site of inflammation. Studies of granulocyte histaminase release in vitro may also provide a new model to explore granulocyte function and secretion.

Inhibition of phagocytosis of complement C3- or immunoglobulin G-coated particles and of C3bi binding by monoclonal antibodies to a monocyte-granulocyte membrane glycoprotein (Mol).

“…Enzyme release from PMN in response to zymosan coated with C3bi was measured as described by Zeiger et al (30). Briefly, 100 Ml PMN at a concentration of 5 X 106/ml in Tris buffer containing 0.1% human serum albumin (HSA), 0.0006 M calcium, and 0.001 M magnesium were incubated at RT with buffer alone or the Fab fragment of monoclonal antibodies to Mol, PLT1 (31), J5 (32), or Mo5 (33) antigens for 25 min.…”

Allergic Bronchial Asthma: Airway Inflammation and Hyperresponsiveness

“…"Modulating cell" refers to the view that eosinophils play favorable roles by controlling allergic inflammation. This view is based on the findings that eosinophils contain arylsulfatase (24), histaminase (25) and phospholipase D (26). "Effector cell"…”

Effects of Proteoglycan on Dextran Sulfate Sodium-Induced Experimental Colitis in Rats

“…In DSS colitis, the degree of eosinophil infiltration does not reflect the severity of the disease or the extent of tissue damage [23]. Eosinophils may act as homeostastic immune modulators and play an anti-inflammatory role, releasing aryl sulfatase B, phospholipase D, histaminase, and other chemical mediators [24][25][26][27]. The eosinophils in the human colonic mucosa account for more overall phagocytic activity than either neutrophils or macrophages [28,29].…”