Plasminogen activator production in a rat model of Pneumocystis carinii pneumonia.
Several studies have indicated that the serine protease urokinase-plasminogen-activator (uPA) is an important factor in host defense against pulmonary pathogens. To gain a better insight into the role of uPA in Pneumocystis carinii (P. carinii) pneumonia (PCP), we evaluated PA production in alveolar macrophages (AMs) obtained from rats with steroid-induced PCP. Treatment with cortisone acetate favored PCP in 91% of rats. In the bronchoalveolar lavage (BAL) samples of immunosuppressed rats both with and without PCP, we observed a decrease in uPA activity as well as a decrease in cell number. Urokinase-PA production by AMs was reduced in rats treated with cortisone alone. However, an increase in cell-associated uPA was observed in rats with PCP. This increase appears to be produced in response to P carinii infection. In fact, when AMs obtained from untreated healthy or immunosuppressed uninfected rats were challenged with P carinii, a significant increase in PA activity in cell lysates was observed, though a lower response was obtained in cortisone-treated animals. Our results suggest that healthy AMs respond to the presence of P carinii with an increase in uPA production and that this response in immunodepressed rat-AMs is partially impaired.
Angelici
E
E
Department of Clinical Medicine, University of Rome La Sapienza, Rome, Italy.
Contini
C
C
Spezzano
M
M
Romani
R
R
Carfagna
P
P
Serra
P
P
Canipari
R
R
D000305:Adrenal Cortex Hormones / Q000009:adverse effects; D000818:Animals; D018753:Diet, Protein-Restricted / Q000009:adverse effects; D007165:Immunosuppression Therapy / Q000379:methods; D016676:Macrophages, Alveolar / Q000276:immunology*; D008297:Male; D011020:Pneumonia, Pneumocystis / Q000276:immunology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*
D000305:Adrenal Cortex Hormones; D014568:Urokinase-Type Plasminogen Activator