German cockroach extract induces activation of human eosinophils to release cytotoxic inflammatory mediators.
BACKGROUND
Eosinophils play an important role in the pathogenesis of allergic diseases. Sensitization and exposure to cockroach allergen have been demonstrated to be one of the major risk factors for the development of bronchial asthma. However, little is known regarding the functional capacity of cockroach extract antigen to activate human eosinophils.


OBJECTIVE
We investigated whether German cockroach extract can activate human eosinophils to release cytotoxic inflammatory mediators.


METHODS
Purified eosinophils from the peripheral blood were incubated with various concentrations (0-200 microg/ml) of German cockroach extract antigen. Effector functions of eosinophils were checked by degranulation and superoxide anion production. In addition, we examined surface expression of CD11b and CD69, and intracellular activation of p38 mitogen-activated protein kinase (p38 MAP kinase) in cockroach-stimulated eosinophils.


RESULTS
German cockroach extract induced degranulation and superoxide production from human eosinophils. In addition, incubation of eosinophils for 3 h with the cockroach extract resulted in an increased level of the surface expression of CD11b and CD69. Furthermore, cockroach-induced superoxide production from eosinophils was significantly inhibited by the pretreatment of cells with a p38 MAP kinase inhibitor SB202190. Indeed, a large amount of phosphorylated forms of p38 MAP kinase was detected in cockroach-stimulated eosinophils.


CONCLUSIONS
Our results suggest that German cockroach extract induces activation of human eosinophils to release cytotoxic inflammatory mediators such as superoxide and granular proteins.
Sohn
Myung-Hyun
MH
Department of Pediatrics and Institute of Allergy, Institute of Tropical Medicine and Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 134 Sinchon-dong, Seodaemun-gu, Seoul 120-752, Korea.
Lee
Young-Ah
YA
Jeong
Kyeong-Yong
KY
Sim
Seobo
S
Kim
Kyu-Eun
KE
Yong
Tai-Soon
TS
Shin
Myeong Heon
MH
D000485:Allergens / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D000943:Antigens, Differentiation / Q000096:biosynthesis / Q000187:drug effects; D015550:Cell Degranulation / Q000187:drug effects; D003058:Cockroaches; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D047208:Eosinophil-Derived Neurotoxin; D004804:Eosinophils / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*; D005089:Exocytosis / Q000187:drug effects; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D015848:Interleukin-5 / Q000008:administration & dosage; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D012260:Ribonucleases / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013481:Superoxides / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
D000485:Allergens; D000943:Antigens, Differentiation; D018836:Inflammation Mediators; D015848:Interleukin-5; D013481:Superoxides; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D047208:Eosinophil-Derived Neurotoxin; D012260:Ribonucleases