Clinical & Experimental Allergy

Induction of T-helper type 2 cytokine release and up-regulated expression of protease-activated receptors on mast cells by recombinant American cockroach allergen Per a 7

Authors

  • Z. Zhang,

    1. The Key Immunopharmacology Laboratory of Guangdong Province, Allergy and Inflammation Research Institute, Shantou University Medical College, Shantou, China,
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  • H. Zhang,

    1. Department of Pathophysiology, Hainan Medical College, Haikou, China
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  • H. Yang,

    1. Clinical Research Centre, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
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  • L. Zhang,

    1. The Key Immunopharmacology Laboratory of Guangdong Province, Allergy and Inflammation Research Institute, Shantou University Medical College, Shantou, China,
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  • X. Chen,

    1. The Key Immunopharmacology Laboratory of Guangdong Province, Allergy and Inflammation Research Institute, Shantou University Medical College, Shantou, China,
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  • X. Zheng,

    1. The Key Immunopharmacology Laboratory of Guangdong Province, Allergy and Inflammation Research Institute, Shantou University Medical College, Shantou, China,
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  • S. He

    1. The Key Immunopharmacology Laboratory of Guangdong Province, Allergy and Inflammation Research Institute, Shantou University Medical College, Shantou, China,
    2. Clinical Research Centre, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
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Correspondence:
Prof. Shaoheng He, The Key Immunopharmacology Laboratory of Guangdong Province, Allergy and Inflammation Research Institute, Shantou University Medical College, 22 Xin-ling Road, Shantou 515041, Guangdong Province, China.
E-mail: shoahenghe@hotmail.com

Summary

Background The cockroach is a major source of indoor allergens, which cause perennial rhinitis and asthma. Per a 7 is one of the major allergens from the American cockroach, eliciting IgE reaction in over 50% of sera from allergic individuals. However, the actions of Per a 7 in the pathogenesis of allergic diseases remain poorly understood.

Objective The aim of the study was to investigate the effects of Per a 7 on the expression of protease-activated receptors (PARs) on murine mast cells and the release of T-helper type 2 (Th2) cytokines from these cells.

Methods Per a 7 gene was cloned and expressed in Escherichia coli. The purified recombinant Per a 7 (rPer a 7) was used to challenge murine mast cells P815 and the expression of PARs was determined by using real-time quantitative RT-PCR and flow cytometry. The release of IL-4 and IL-13 was detected with ELISA.

Results rPer a 7 was solubly expressed in E. coli and the purified rPer a 7 reacted with 75% (six out of eight) of the sera from cockroach-allergic patients. Following stimulation of rPer a 7, the expression of PAR-1, PAR-2, PAR-3 and PAR-4 mRNAs on P815 cells increased by 8.7-, 6.8-, 14.4- and 8.8-fold, respectively, following 2- and 6-h incubation periods, and the expression of PAR-1, PAR-2 and PAR-4 proteins was enhanced following 16-h incubation. rPer a 7 provoked approximately up to a 4.8- and 2.3-fold increase in IL-4 and IL-13 release from P815 cells following 6- and 16-h incubation periods.

Conclusion rPer a 7 induced up-regulation of PAR expression on P815 cells and provoked Th2 cytokines IL-4 and IL-13 secretion from these murine mast cells, which implicated that this major cockroach allergen is likely to contribute to the development of cockroach-related allergic disease.

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