Type I allergy is an immunoglobulin E (IgE)-mediated hypersensitivity disease affecting more than 25% of the population. Currently, diagnosis of allergy is performed by provocation testing and IgE serology using allergen extracts. This process defines allergen-containing sources but cannot identify the disease-eliciting allergenic molecules. We have applied microarray technology to develop a miniaturized allergy test containing 94 purified allergen molecules that represent the most common allergen sources. The allergen microarray allows the determination and monitoring of allergic patients' IgE reactivity profiles to large numbers of disease-causing allergens by using single measurements and minute amounts of serum. This method may change established practice in allergy diagnosis, prevention, and therapy. In addition, microarrayed antigens may be applied to the diagnosis of autoimmune and infectious diseases.
Ves v 5 is one of three major allergens found in yellow-jacket venom: phospholipase A(1) (Ves v 1), hyaluronidase (Ves v 2), and antigen 5 (Ves v 5). Ves v 5 is related by high amino acid sequence identity to pathogenesis-related proteins including proteins from mammals, reptiles, insects, fungi, and plants. The crystal structure of Ves v 5 has been solved and refined to a resolution of 1.9 A. The majority of residues conserved between the pathogenesis-related proteins can be rationalized in terms of hydrogen bonding patterns and hydrophobic interactions defining an alpha-beta-alpha sandwich core structure. A small number of consensus residues are solvent exposed (including two adjacent histidines) and located in an elongated cavity that forms a putative active site. The site has no structural resemblance to previously characterized enzymes. Homologous antigen 5's from a large number of different yellow jackets, hornets, and paper wasps are known and patients show varying extents of cross-reactivity to the related antigen 5's. The structure of Ves v 5 allows a detailed analysis of the epitopes that may participate in antigenic cross-reactivity, findings that are useful for the development of a vaccine for treatment of insect allergy.
Bees, fire ants and vespids cause insect sting allergy. These insects have unique as well as common venom allergens. Vespids, including hornets, paper wasps and yellow jackets, have common allergens. Bees and vespids have one common allergen with hyaluronidase activity; they also have unique allergens with different phospholipase activities. Fire ants and vespids have one common allergen, antigen 5 of unknown biologic activity. The common venom allergens with < 70% sequence identity have barely detectable levels of antigenic cross-reactivity. Possible uses of modified allergens for immunotherapy are described.
Proteins can be modified at their amino groups under gentle conditions to contain an average of three to six aryl aldehyde or acyl hydrazide groups. These two types of modified proteins at about 10 microM concentration condense with each other at pH approximately 5 to form conjugates linked by hydrazone bonds. Under proper conditions conjugates mainly of dimers and trimers in size or, if desired, higher oligomers can be obtained. The conjugates can be dissociated to their individual protein components by an exchange reaction with an excess of acetyl hydrazide. The reversible hydrazone bonds of conjugates can be reduced with NaCNBH3 to give stable hydrazide bonds. The stability of protein-hydrazone conjugates was found to be significantly greater than that of the model compound, the N-acetylhydrazone of p-carboxybenzaldehyde. This difference is believed to result from the presence of multiple hydrazone linkages in protein conjugates.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.