Immunogenicity and allergenicityof recombinant Der p2 mutant allergen

Abstract

Objective To observe the immunogenicity and allergenicity of recombinant house dust mite Der p2 allergen (rDer p2) mutants. Methods Der p2's IgE epitope was deleted . The DNA encoding Der p2 mutant were synthesized and cloned into pET32a plasmid. rDer p2 mutant were expressed in E. coli(BL21) and purified through Ni+ NTA. Balb/c mice were sensitized by rDer p2 or rDer p2 mutant. The levels of IgE, IgG1, and IgG2a antibody in serum were determinate by enzyme-linked immunosorbent assay(ELISA). The binding ability of rDer p2 mutant with IgE was measured by dot immunobirding assay. Results rDer p2 mutant was expressed and purified. The first day after immunization, the levels of IgG1, IgG2a, and IgE antibody had no obvious difference between rDer p2 and rDer p2 mutant group(P=0.067, P=0.052, P=0.078). After 7 days of immunization, the levels of IgG1 antibody had no significant difference between rDer p2 and rDer p2 mutant (P=0.0612). However, the level of IgE antibody in rDer p2 mutant group was lower than rDer p2 (P=0.002) group.The level of IgG2a antibody in rDer p2 mutant group was lower than rDer p2 group (P=0.0056). After 14 days, the level of IgE antibody in rDer p2mutant group was much lower than rDer p2 group (P=0.001). The level ofIgG2a antibody in rDer p2 mutant group was much lower than rDer p2group(P=0.0034). Compared with rDer p2, rDer p2 mutant had the weak binding ability with house dust mites allergic patients. Conclusion rDer p2 mutant could induce mice to produce IgG2a, IgG1 antibody and to reduce IgE antibody production at the same time. rDer p2 mutant exhibited best immunogenicity and lower allergenicity. Key words: Dermatophagoides pteronyssinus; Der p2 mutant; Immunogenicity; Allergenicity