Effect of imported fire ant extract on the degradation of mountain cedar pollen allergen.

Background: Dust mite, cockroach, and mold extracts have been shown to contain proteases capable of degrading the proteins in other extracts. Loss of potency of allergens has been reported in mixtures containing cockroach and fungal extracts. Fire ant venoms consist of 90% to 95% n-alkyl and n-alkenyl piperidine alkaloids, which are not allergenic. No studies are available addressing the mixture of imported fire ant (IFA) whole-body extract with other allergens or the presence of proteolytic activity in the venom extract.

Objectives: To evaluate the stability of mountain cedar pollen extract mixed with IFA whole-body extract and to qualitatively analyze the extract mixture for degradation of mountain cedar protein.

Methods: One milliliter each of mountain cedar and IFA whole-body extracts at a concentration of 500 microg/mL were combined and stored at 4 degrees C for 1, 3, 6, 15, 30, 60, 90, and 180 days. Separate mixtures of 1 mL of mountain cedar and IFA with 1 mL of human serum albumin were used as controls. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was performed, and protein bands were qualitatively analyzed for degradation.

Results: We detected 3 distinct IFA protein bands and 1 mountain cedar protein band. With respect to these bands, no protein degradation was observed during 6 months of study in the extract mixture compared with the controls.

Conclusions: Imported fire ant whole-body extract does not seem to degrade mountain cedar protein. Mixtures of allergenic extracts may be able to include IFA whole-body extract.