Comparison of apis mellifera natural and commercial venoms by proteomic and electrophoretic approaches

Comparison of apis mellifera natural and commercial venoms by proteomic and electrophoretic approaches Riccio, AM1; De Ferrari, L1; Rossi, R2; Mauri, P2; Rogkakou, A1; Bonadonna, P3; Vega, A4; Castells, M5; Bignardi, D6; Lombardo, C3; Galli, L7; Benvenuti, M7; Pravettoni, V8. 1Allergy and Respiratory Diseases, IRCCS San Martino- IST-University of Genoa, Genoa, Italy; 2Institute for Biomedical Technologies Segrate, Milan, Italy; 3Allergy Unit, University Hospital of Verona, Verona, Italy; 4Hospital de Guadalajara, Guadalajara, Spain; 5Brigham and Women's Hospital, Boston, United States; 6Allergy Unit IRCCS San Martino-IST-University of Genoa, Genoa, Italy; 7Entomology DISTAV University of Genoa, Genoa, Italy; 8Fondazione IRCCS C_a Granda Ospedale Maggiore Policlinico Milan, Milan, Italy Background: Honeybee's venom, is a complex mixture of amines, peptides and proteins. A sting can inject 50 to 140 micrograms of protein, which can be responsible for IgE mediated reactions. Actually, at least 12 proteins are acknowledged as allergens, such as Phospholipase (Api m 1) and Hyaluronidase (Api m 2), Api m 6, 7 and 10. Hymenoptera venom immunotherapy (VIT) is effective in >80% of allergic patients. Nonetheless, some patients are not protected by VIT. We assessed and compared the characteristic of fresh bee venom and commercial preparations by omic and electrophoretic techniques. Method: The fresh venom was collected by our entomologists inducing the live insects to sting a parafilm. The drops of venom were then collected and frozen. Three different commercial VIT preparations were compared. Samples underwent electrophoresis by poliacrilammide pre-cast 4-12% and Silver Stain. Aliquots were also analyzed by proteomic approach (Mud- PIT) with tandem mass spectrometry (2DC-MS/MS). A list of the identified proteins was then obtained by dedicated software. Results: Gel electrophoresis and proteomic analyses evidenced important quantitative and qualitative differences between fresh venom and commercial products and among commercial products. The major allergens (Api m 1 and Api m 4) were present in all products, at lower concentration than in the natural venom. Api m 2 and preApi m 10 were absent in some products. Api m 3, Api m 3-like, Api m 5, pre-Api m 11.0101, pre-Api m 11.0201 were detected only in the natural fresh venom. Conclusion: Although the efficacy of VIT is well proven, the different composition of commercial venoms vs the natural venom, could explain some clinical phenomena such as the lack of response in some pestients.