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.
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.


CONCLUSIONS
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.
Zhang
Z
Z
The Key Immunopharmacology Laboratory of Guangdong Province, Allergy and Inflammation Research Institute, Shantou University Medical College, Shantou, China.
Zhang
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H
Yang
H
H
Zhang
L
L
Chen
X
X
Zheng
X
X
He
S
S
D000485:Allergens / Q000276:immunology*; D000818:Animals; D052179:Antigens, Plant; D045744:Cell Line, Tumor; D003058:Cockroaches / Q000276:immunology*; D015870:Gene Expression; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D018793:Interleukin-13 / Q000096:biosynthesis / Q000276:immunology; D015847:Interleukin-4 / Q000096:biosynthesis / Q000276:immunology; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D044462:Receptors, Proteinase-Activated / Q000378:metabolism*; D011994:Recombinant Proteins / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism; D015854:Up-Regulation
D000485:Allergens; D052179:Antigens, Plant; D018793:Interleukin-13; D044462:Receptors, Proteinase-Activated; D011994:Recombinant Proteins; C118755:allergen Per a 7, Periplaneta americana; D015847:Interleukin-4; D007073:Immunoglobulin E