secapin and mast-cell-degranulating-peptide

Treatment with aqueous and aluminum hydroxide (Al[OH](3))-adsorbed purified honeybee (Apis mellifera) venom (HBV) preparations can reduce the incidence of side effects associated with venom immunotherapy.. The aim of the present study was to assess these purified HBV immunotherapy preparations in situ.. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was used to visualize the distribution of HBV components. The preparations were administered on the back legs of naive Wistar rats. The rats were killed, and cryosectioned tissue sections were subjected to hematoxylin and eosin staining and MALDI-MSI analyses.. Low-density maps of tissue distribution of HBV peptides, such as secapin, mast cell degranulating peptide, and melittin (Api m 4) were detected in the tissue after administration of HBV immunotherapy preparations. In addition, release of biogenic amines, cytokines, and leukotrienes was observed, and the distribution of HBV allergens, such as Api m 1 and Api m 2, was shown. At the 24-hour time point, the major HBV allergen Api m 1 was still detected at the site of Al(OH)(3)-adsorbed HVB injection, whereas in the case of aqueous HBV preparation, all the allergens, as well as most of the biogenic amines, were cleared at the 24-hour time point.. The present study shows that the majority of low-molecular-weight HBV components are rapidly removed from the site of venom immunotherapy administration. Furthermore, Al(OH)(3)-adsorbed HBV preparation demonstrated a depot effect, prolonging the availability of bee venom allergens at the site of administration.

Topics: Allergens; Aluminum Hydroxide; Animals; Antigens, Plant; Bee Venoms; Bees; Biogenic Amines; Cryoultramicrotomy; Desensitization, Immunologic; Humans; Hyaluronoglucosaminidase; Hypersensitivity; Insect Proteins; Lasers; Melitten; Peptides; Phospholipases A; Rats; Rats, Wistar; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Water

The aim of the study was to comprehensively characterize different honeybee venom samples applying two complementary mass spectrometry methods. 41 honeybee venom samples of different bee strains, country of origin (Poland, Georgia, and Estonia), year and season of the venom collection were analyzed using MALDI-TOF and nanoESI-QqTOF-MS. It was possible to obtain semi-quantitative data for 12 different components in selected honeybee venom samples using MALDI-TOF method without further sophisticated and time consuming sample pretreatment. Statistical analysis (ANOVA) has shown that there are qualitative and quantitative differences in the composition between honeybee venom samples collected over different years. It has also been demonstrated that MALDI-TOF spectra can be used as a "protein fingerprint" of honeybee venom in order to confirm the identity of the product. NanoESI-QqTOF-MS was applied especially for identification purposes. Using this technique 16 peptide sequences were identified, including melittin (12 different breakdown products and precursors), apamine, mast cell degranulating peptide and secapin. Moreover, the significant achievement of this study is the fact that the new peptide (HTGAVLAGV+Amidated (C-term), M(r)=822.53Da) has been discovered in bee venom for the first time.

Topics: Amino Acid Sequence; Animals; Bee Venoms; Bees; Estonia; Georgia; Melitten; Nanotechnology; Peptide Mapping; Peptides; Poland; Spectrometry, Mass, Electrospray Ionization; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Secondary structure analysis of apamin, mast cell degranulating peptide, tertiapin and secapin has been attempted, based on parameters produced by Levitt (Biochemistry (1978) 17, 4277--4285). The structural model, recently advanced for apamin, based on Chou and Fasman's parameters was confirmed. The predicted structure for mast cell degranulating peptide is almost spherical with the eight positive centres evenly distributed over the surface. On the basis of this analysis and related spectroscopic evidence, it is suggested that these four peptides share a common folding pattern, which is centered on a beta-turn covalently linked to an alpha-helical segment by two disulphide links (one disulphide link in the case of secapin). It is further suggested that apamin, mast cell degranulating peptide and tertiapin form a single molecular class.

Topics: Amino Acid Sequence; Apamin; Bee Venoms; Circular Dichroism; Models, Molecular; Peptides; Protein Conformation