IgE Reactivity of Recombinant Pac c 3 from the Asian Needle Ant (Pachycondyla chinensis)

Background: Stingsfrom the Asian needle antare an important cause of anaphylaxisin East Asia. A 23-kDa protein homologous to antigen 5 is the major allergenproduced by these ants. In this study, we aimed to produce a recombinant antigen 5 allergen, Pac c 3. Methods: Recombinant Pac c 3 allergenfrom the Asian needle antwas expressed in Pichia pastorisand purified by ammonium sulfate precipitationand Ni affinity chromatography. IgE reactivity was demonstrated by ELISA and immunoblotting. Results: The recombinant protein was recognized in 5 of 6 (83.3%) serum samples from patients with demonstrated anaphylaxisto ants. IgE reactivity to an antigen 5 allergenfrom Asian needle ant venomsac extract was specifically inhibited by the recombinant protein. It was also able to inhibit IgE binding to the vespid allergenVes v 5 by ImmunoCAP analysis, indicating the presence of cross-reactivity. Conclusion: A recombinant Pac c 3, cross-reactivewith Ves v 5, from the Asian needle antwas successfully produced in the methylotrophicyeast P. pastoris. This protein could be useful for the development of component-resolved diagnostics.