Background: Recommendations regarding the administration of imported fire ant whole body extract (IFA WBE) combined with aeroallergens or environmental allergens in a single immunotherapy injection are lacking.
Objective: To evaluate the degradative effect of IFA WBE on cat, ragweed, Dermatophagoides pteronyssinus, and timothy grass allergens.
Methods: Imported fire ant whole body extract was combined with extracts of cat, ragweed, D pteronyssinus, and timothy grass. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed on each sample after storage for 0, 1, 3, and 6 months at 4 degrees C. In addition, cat and ragweed combinations were evaluated by radial immunodiffusion (RID); D pteronyssinus by enzyme-linked immunosorbent assay (ELISA) inhibition; and timothy grass by ELISA inhibition and Western blot.
Results: Imported fire ant whole body extract combined with timothy grass demonstrated degradation of timothy grass allergens by SDS-PAGE, ELISA inhibition, and Western blot results. Cat and ragweed allergens were stable after mixing with IFA WBE, based on SDS-PAGE and RID analyses. Stability of D pteronyssinus allergens with IFA WBE was evident from SDS-PAGE and ELISA inhibition data.
Conclusions: Imported fire ant whole body extract combined with timothy grass resulted in significant and rapid timothy protein degradation. Imported fire ant whole body extract mixed with cat, ragweed, or D pteronyssinus revealed aeroallergen stability, yielding the possibility of combining these extracts in a single immunotherapy injection. Compatibilities of IFA WBE with other common aeroallergens remain undetermined and thus are not recommended for single-injection immunotherapy formulations.