Effect of proteolytic activity of Epicoccum purpurascens major allergen, Epi p 1 in allergic inflammation

• Published in: Clinical and experimental immunology Vol. 154; no. 2; pp. 162 - 171
• Main Authors: Kukreja, N., Sridhara, S., Singh, B. P., Arora, N.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.11.2008; Blackwell; Blackwell Science Inc
• Subjects: allergen; Allergens - immunology; Allergens - isolation & purification; allergic inflammation; Analytical, structural and metabolic biochemistry; Animals; Antigens, Plant; Biological and medical sciences; Bronchoalveolar Lavage Fluid - immunology; Cell Proliferation; Cells, Cultured; Cytokines - biosynthesis; Disease Models, Animal; Eosinophil Peroxidase; Epicoccum; Epicoccum purpurascens; Female; Fundamental and applied biological sciences. Psychology; Immunization - methods; Immunoglobulin E - biosynthesis; Immunoglobulin E - blood; Immunoglobulin G - biosynthesis; Immunoglobulin G - blood; Lung - immunology; Lung - pathology; Mice; mice model; Mice, Inbred BALB C; Ovalbumin - immunology; Phytohemagglutinins - immunology; Respiratory Hypersensitivity - immunology; Respiratory Hypersensitivity - pathology; Serine Endopeptidases - immunology; Serine Endopeptidases - isolation & purification; serine protease; Spleen - immunology; Translational Studies; Immunopathology; Allergy; Animal model; allergic inflammation; Serine endopeptidases; Enzyme; Rodentia; mice model; Biochemistry; Inflammation; serine protease; Biological activity; Peptidases; Vertebrata; Mammalia; Mouse; Proteolysis; Hydrolases; Epicoccum purpurascens; Allergen
• ISSN: 0009-9104; 1365-2249
• DOI: 10.1111/j.1365-2249.2008.03762.x

Summary Enzymes play an important role in inducing airway inflammation, but knowledge is limited to few proteins. This study was carried out to assess the role of Epi p 1, a serine protease of Epicoccum purpurascens, in inducing allergy and inflammation in a murine model. Balb/c mice were sensitized with Epi p 1 active protease (EAP) or Epicoccum extract. Subsequently, Epi p 1 sensitized mice were boosted on day 14 with EAP or inactivated protease (EIAP). Three intranasal challenges were given and mice were killed to obtain blood, bronchoalveolar lavage fluid (BALF), spleen and lung tissues. Cellular airways infiltration, immunoglobulin E (Ig)E titres and cytokine levels in BALF and splenocyte culture supernatant were compared. Mice immunized with EAP had higher Epi p 1‐specific serum IgE and IgG1 than EIAP immunized mice (P < 0·01). There was a twofold difference in the number of eosinophils in BALF of EAP mice and EIAP mice (P < 0·01). A similar trend was recorded for eosinophil peroxidase activity (P < 0·05), indicating the role of proteolytic activity in inducing inflammation. Further, lung histology revealed increased leucocyte infiltration and airway narrowing, with higher inflammation scores in the EAP group than in the EIAP group. The lungs of EAP mice showed increased mucus and goblet cell metaplasia. Interleukin (IL)‐4 and IL‐5 levels were higher in BALF and splenocyte culture supernatant of EAP mice than in EIAP mice (P < 0·05), indicating a T helper 2 response. Proteolytic activity of Epi p 1 plays an important role in inducing allergic inflammation. The enzymatically inactive form may be investigated for immunotherapy.