Serine proteinase from Staphylococcus aureus enhances elastin degradation by elastases in the presence of human alpha-1-proteinase inhibitor.

During staphylococcal pneumonia massive destruction of lung tissue is often observed. Staphylococcal serine proteinase (SSP) inactivates alpha-1-proteinase inhibitor (alpha 1PI) a major factor which protects lungs from phagocyte proteases. We investigated the effect of SSP on elastin degradation by porcine pancreatic elastase (PE) and crude extract of human neutrophil elastase (NE) in solution and gel containing alpha 1PI. SSP having no elastase activity enhanced PE and NE-induced elastinolysis in solution when added to alpha 1PI before mixing with elastase and then with elastin. SSP added simultaneously with alpha 1PI to PE had no influence on elastin degradation. However, SSP added simultaneously, 30 min before or 30 min after PE significantly increased elastin digestion in elastin-agarose plate with alpha 1PI. Maximal increase in elastinolysis about 3-fold was for SSP added 30 min prior to PE. Since elastin is the major component of the alveolar walls it is possible that lung damage in the course of staphylococcal infection may partly depend on action of SSP.