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Secretory phospholipase A 2 activity is elevated in bronchoalveolar lavage fluid after ovalbumin sensitization of guinea pigs
Author(s) -
Sane Aneysa C.,
Mendenhall Tiffany,
Bass David A.
Publication year - 1996
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.60.6.704
Subject(s) - bronchoalveolar lavage , ovalbumin , sensitization , phospholipase a2 , arachidonic acid , antigen , guinea pig , immunology , biology , chemistry , lung , medicine , endocrinology , enzyme , biochemistry
Arachidonic acid (AA), the precursor of eicosanoids, is released from the sn‐2 position of phospholipids by both secretory (8PLA 2 ) and cytosolic phospholipase A 2 (CPLA2). Eicosanoids have been shown to contribute to bronchospasm in asthma. We measured the enzymatic activity of 8PLA 2 and CPLA 2 in the bronchoalveolar lavage fluid and cells, respectively, in male Hartley guinea pigs sensitized with ovalbumin. sPLA 2 activity was also measured from alveolar macrophages (AM) in culture from unsensitized and sensitized animals. There was an increase in 8PLA 2 activity and AA content in the lavage fluid following sensitization (18.73 ± 1.33 to 25.74 ± 3.22% hydrolysis and 17.97 ± 12.39 to 44.76 ± 13.37 pmol AA/mL BAL, mean ± SD), which remained elevated but without further increase 4 or 24 h after antigen challenge. AM from unsensitized and sensitized‐unchallenged animals did not secrete 8PLA2 activity in culture for 3 h and therefore do not appear to be the cell source of the sPLA 2 activity present in the alveolar lavage fluid following OA sensitization. In contrast to the increase in 8PLA 2 in lung lavage fluid, Western blotting for CPLA 2 from lung lavage cells showed no increase 4 or 24 h after antigen challenge compared with sensitization alone. CPLA 2 enzymatic activity of the cytosol fraction of lung lavage cells showed no changes with antigen sensitization or challenge. In summary, intraperitoneal sensitization with ovalbumin in male Hartley guinea pigs caused an increase in both sPLA 2 and AA in bronchoalveolar lavage fluid without a need for antigen challenge. The increased 8PLA 2 enzymatic activity following sensitization may be responsible for the elevation of AA in the bronchoalveolar lavage fluid observed after antigen sensitization. J . Leukoc . Biol . 60: 704–709; 1996.