PEGylation and immunological characterization of rBla g 2 allergen / 中华微生物学和免疫学杂志

ABSTRACT

Objective To research the effect of PEGylation on rBla g 2 from Blattella germanica.Methods rBla g 2 allergen expressed in E.coli was purified by Ni+affinity chromatographY,then was PEGylated by mPEG2-NHS(Mr,10×103).The PEG-rBla g 2 was purified by CM-Sepharose,a cation exchange chromatography. SDS-PAGE,Western blot and ELISA were used to characterize its biologicat actovoty.Results The relative molecular mass of the purified rBla g 2 was about 39×1023.PEG-rBla g 2 was analyzed by SDS-PAGE.Five bands were visualized by staining with Coomassie Brilliant Blue R-250,while seven bands by staining with I2-KI.Cation exchange chromatography could separate rBla g 2 and PEG-rBla g 2.The 100×103(Mr)and 130×103(Mr)of PEG-rBla g 2 could combined with the special IgE from sera of one cockroach-allergic patient by Western blot.The immunological activities of PEG-rBla g 2 in vitro decreased remarkablv bv ELISA,which was only 42%of rBla g 2.Conclusion PEGylated allergen can retain the ability of combining with special IgE from sera,while its immunological activities reduce enormously,which establishes the basic work of researching recombinant low-sensitive allergens.