Studies on the role of polymorphonuclear leukocyte granule elastase in Arthus reaction

In the present study, attempts were made to clarify the role of an elastase-like enzyme in Arthus reaction by using rabbit-peritoneal polymorphonuclear leukocytes (PMNs). It was first confirmed that the injection of large amounts of PMNs with antibody can increase tissue damage in reversed Arthus reaction. The five various fractions, which were intact PMNs, whole homogenate, granule fraction, nuclei and cell debris, and membrane extract, were prepared from rabbit-peritoneal exudate. Each fraction was intracutaneously injected into the abdominal wall of rabbit. It was of particular interest that the tissue damage induced by membrane extract occurred earlier and was more severe than that caused by the others. Furthermore, membrane extract possessed remarkably higher caseinolytic and elastinolytic activities than the others. The membrane extract was partially purified by Sephadex G-100 column chromatography. The protein concentration of the elastase-like enzyme solution was 3.64 mg/ml, and its specific activity was 195 caseinolytic units and 0.45 elastinolytic units per milligram of protein. The cutaneous reaction by membrane extract was dependent on the concentration of this elastase-like enzyme and could be strongly inhibited by Elastatinal. From these results, the authors suggest that an elastase-like enzyme which originates in PMN granules is the key enzyme that promotes the severity of tissue damage in Arthus reaction.