Elastase activity in granulomatous inflammation in experimental murine leprosy.

Proteolytic activity for [3H]elastin, pyro-Glu-Pro-Val-pNA(S-2484), and Suc-(Ala)3-pNA(AAApNA) was demonstrated in the bound fraction extracted with 2 M KSCN + 0.1% Triton X-100 from hypersensitivity-type murine lepromas in C57BL/6N mice, while elastase-inhibitor activity was separately observed in the soluble fraction extracted with a Tris-saline buffer. Sephacryl S-200 gel chromatography showed a peak of elastolytic activity with approximately 20,000 in molecular weight. The following DEAE-Sepharose chromatography demonstrated three fractions of elastolytic activity (E-I, II, III). The inhibitory profile showed that E-I is a thiol proteinase, while E-II and E-III belong to serine proteinase-type elastases. Both E-II and E-III showed different properties with neutrophil elastase or elastase secreted from cultured macrophages, but identical characteristics to membrane bound-type elastase of monocytes. A lower level of elastolytic activity was detected in the bound fraction of nonhypersensitivity-type murine lepromas in CBA/N mice, suggesting a more involvement of membrane bound-type elastase from monocytes/macrophages during the tissue remodelings of hypersensitivity-type granulomas.