In Vivo Studies with the Partially Purified Protease (Elastase) from Pseudomonas aeruginosa

An extracellular protease from Pseudomonas aeruginosa exhibiting elastase activity was characterized in vivo after an 80- to 100-fold purification by chemical and chromatographic procedures. The lethality of different samples for white, female mice was determined by intravenous, intranasal, intraperitoneal, and subcutaneous injections. The purified protease exhibited the following 48-hr LD(50) values: intraperitoneally, 9.0 protease units; intranasally, 31.5 protease units; and intranasally, 0.3 protease unit. In the concentrations tested no lethality was observed when the subcutaneous route was employed. Gross and microscopic studies revealed that purified protease was capable of eliciting a variety of tissue responses in mice depending upon its route of administration. Intraperitoneal injections resulted in gastrointestinal tract serosal hemorrhage and necrosis. Intranasal and intravenous injections produced pulmonary hemorrhage, whereas subcutaneous injections resulted in black, necrotic, ulcerating lesions.