Débora Laís Justo Jacomini , MD 1 , Franco Dani Campos Pereira 1 , José Roberto Aparecido dos Santos Pinto , MD 2 , Lucilene Delazari dos Santos , PhD 2 , Anally Ribeiro da Silva Menegasso 2 , Mário Sérgio Palma , PhD 2 , Ricardo de Lima Zollner , PhD 3 , Márcia Regina Brochetto-Braga , PhD 1
17 February 2012
Between 9.3 and 28.5% of world population are estimated to be allergic to the protein components of Hymenoptera venom and among them, the hyaluronidase (HYAL) is one of the most important, although the nature of its IgE binding epitopes is unknown.
Enzyme was purified from P. paulista venom by cation exchange chromatography in AKTA-FPLC system with a Hiprep CM FF column. Fractions with HYAL activity were pooled, lyophilized, dialyzed against distilled water in presence of protease inhibitor (PMSF) and subjected to SDS-PAGE 15%. The only protein bands visualized were submitted to tryptic digestion and to MALDI-ToF/ToF mass spectrometry. Digested peptides produced were compared with partial/complete protein sequences from Data Bank including with the HYAL (Q9U6V9) of Polistes annularis venom used as model. Western blotting was performed with Pp-HYAL-specific antibody to test the identity of pure protein.
All analysis performed identified the pure protein as an HYAL present in P.paulista venom, which also had its cDNA sequence (GI:302201582) cloned and determined in previous studies, being its high similarity with the Polistes annularis enzyme already confirmed. The mature allergenic protein has 338 amino acids and a molecular weight of 39 KDa. The same allergen is known in other insects, venoms and immunological cross reactivity may sometimes be observed among closely related species. Here, the immunoblotting assay revealed that the Pp-HYAL-specific antibody used recognized the correspondent protein in the purified fraction and in the crude venom of P. paulista, but not in the Apis mellifera and Solenopsis invicta venoms.
The methodology used was able to purify the allergen, which is a key step in the characterization of its binding epitopes. Such knowledge has direct implications in accuracy of diagnostic procedures and strategies for specific immunotherapy of allergic patients to the venom of this insect.
Funding: Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).