Type I skin reactivity to native and recombinant phospholipase A2 from honeybee venom is similar

Phospholipase A2 is the major allergen in honeybee venom. Recombinant phospholipase A2 was produced in prokaryotes and tested for its biologic activity by intracutaneous skin testing with serial 10-fold dilutions in comparison with native and deglycosylated phospholipase A2 in patients allergic to bee venom. Linear regressions of the log of the wheal area versus the log of the allergen concentration were calculated for all allergens in each patient. The relative allergenic potency of the various preparations was analyzed by comparing the linear regressions. Native phospholipase A2 was about 10 times more potent than whole bee venom. None of 58 patients allergic to bee venom was missed by testing with native phospholipase A2 alone. This allergen and deglycosylated native phospholipase A2 resulted in similar skin reactions, indicating that the sugar residues were of little relevance for IgE-binding in the patients tested. Native phospholipase A2 also had relative potency similar to that of recombinant refolded phospholipase A2, whereas recombinant nonrefolded phospholipase A2 had almost no biologic activity in skin testing. These results demonstrate in vivo activity of the recombinant bee venom allergen phospholipase A2. Although correct refolding is a prerequisite for type I skin reactivity, glycosylation seems to be less important.