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The Crystal Structure of Sol i 3, a Major Fire Ant Venom Allergen
Abstracts S243
J ALLERGY CLIN IMMUNOL VOLUME 123, NUMBER 2
Prevalence Of Hymenoptera Venom Allergy In 13-18 Years Old Thai Children S. Sittisomwong, MD, P. Sangsupawanich, MD, PhD; Allergy and Immunology Unit, Pediatric Department, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand. RATIONALE: Prevalence of Hymenoptera venom hypersensitivity has not been systematically estimated in Thai children. We sought to determine the prevalence of insect sting allergy among 13 -18 years old children in Hat Yai, Thailand. METHODS: A self-report insect allergy questionnaire was administered to 2,000 children age 13 -18 years across Had Yai, Thailand. Skin prick test with 4 hymenoptera allergens (honey bee, mixed wasp, yellow hornet venom and fire ant whole body extract) were convinced on all Hymenoptera-allergic subjects. Subjects with history of severe Hymenoptera allergic reaction and positive skin prick test to Hymenoptera venom were informed for the role of venom immunotherapy. RESULTS: One thousand eight hundred and forty eight questionnaires were available for analysis. Of these, 15.3% had a large local reaction (LLR), 15.4% had a mild to moderate systemic reaction (MSR), and 1.6% had a severe systemic reaction (SSR). One hundred and nine subjects underwent insect venom skin test. The positive rate of sensitization to honey bee, mixed wasp, yellow hornet and fire ant were 0.9%, 1.8%, 5.5% and 33.9%, respectively. CONCLUSIONS: This is the first prevalence survey of systemic sting reactions in Thailand which fire ant venom is the most common insect allergic sensitization among Thai teenagers.
940
The Crystal Structure of Sol i 3, a Major Fire Ant Venom Allergen D. R. Hoffman1, S. Padavattan2, M. Schmidt3, Z. Markovic’-Housley2; 1 Brody School of Medicine at East Carolina University, Greenville, NC, 2 Biozentrum, University of Basel, Basel, Switzerland, 3East Carolina University, Greenville, NC. RATIONALE: Sol i 3 is a member of the wasp antigen 5 family, but IgE antibodies from fire ant venom allergic patients do not show significant cross-reactivity with vespid wasp antigen 5’s. METHODS: Recombinant Sol i 3 was produced in baculovirus with a Cterminal hexahistidine. The carbohydrate free form was isolated by cation exchange chromatography and crystallized by hanging-drop vapor diffusion. Diffraction data were collected to 3.05 angstrom from a single crystal at the Swiss Light Source. The images were indexed and integrated using the MOSFILM program and the structure solved by molecular replacement using PHASER with the structure of Ves v 5. PROCHECK showed 90.1% of the residues within the allowed region of the Ramachandran plot. RESULTS: There were two monomers of Sol i 3 per asymmetric unit with 70% solvent content. The secondary structure is arranged in an a-b-a sandwich fold consisting of a central antiparallel b-sheet surrounded on both sides by a-helices. The overall structure is very similar to Ves v 5 with major differences in the solvent exposed loop regions including amino acid insertions. There is very limited conservation of surface chemistry and topology, supporting the observation of very limited cross-reactivity with Ves v 5. The molecular surface of Sol i 3 can accommodate four unique Sol i 3 epitope regions. CONCLUSIONS: The three-dimensional structure of Sol i 3 shows little surface conservation with Ves v 5, providing a structural basis for the observed lack of antigenic cross-reactivity.
941
Mountain Pine Beetle: A New Aero-Allergen D. F. Stark, A. H. Y. Li; UBC, Vancouver, BC, Canada. RATIONALE: This study identifies a new aero-allergen thought to be caused by the migration and aerosolization of mountain pine beetle allergens in the interior of British Columbia. The mountain pine beetle population of British Columbia has traditionally been a stable resident of the natural eco-system for many years. Recent changes in the environment and forestry practices have resulted in a mountain pine beetle epidemic and raised the question as to whether this could cause allergic sensitization. Mountain pine beetles undertake a mass annual migration flying to new food sources of pine trees to assist in its reproductive cycle. This mass migration results in the simultaneous flight of millions of mature pine beetles from the affected area in central British Columbia. METHODS: To investigate the possibility of patient sensitization with the mountain pine beetle, an allergy extract was prepared with a saline solution, filtered by a micropore filter, and stabilized with 50% glycerol. Out-patients who visited the Prince George Allergy Clinic from September 2007 to April 2008 with allergy symptoms were allergy skin tested with this pine beetle extract. A control population was used in Vancouver. RESULTS: The prevalence of pine-beetle allergic reactivity was 32% in central British Columbia and in the Vancouver area 7%. Patients were also routinely skin tested with cockroach and dust mite allergens. Results of our studies show that there was some cross-reactivity between cockroach and mountain pine beetle reactivity. CONCLUSIONS: In conclusion this is the first study identifying mountain pine beetle allergic sensitization as a new aero-allergen.
942
Cross reactivity between European Hornet and Yellow Jacket venoms. M. G. Severino1, B. Caruso2, P. Bonadonna3, D. Labardi4, D. Macchia1, P. Campi1, G. Passalacqua5; 1Allergy & Clinical Immunology Unit, Azienda Sanitaria di Firenze, Firenze, Italy, 2Laboratory of Clinical Chemistry and Haematology, Verona General Hospital, Verona, Italy, 3Allergy Service, Verona General Hospital, Verona, Italy, 4Anallergo SpA, Firenze, Italy, 5Allergy & Respiratory Diseases DIMI, Genoa University, Genoa, Italy. BACKGROUND: Cross-reactions between venoms may be responsible for multiple diagnostic positivities in hymenoptera allergy. There are few data available on the cross-reactivity among Vespula germanica and Vespa crabro, being this latter an important cause of severe reactions in some European countries. We studied by CAP-inhibition assays and immunoblotting the cross-reactivity between the two venoms. METHODS: Sera from patients with non discriminative skin/CAP positivity to both Vespula and Vespa Crabro were collected for the analyses. Inhibition assays were carried out with a CAP method, incubating the sera separately with both venoms and subsequently measuring the specific IgE to venoms themselves. Immunoblotting was performed on sera with ambiguous results at the CAP-inhibition. RESULTS: Seventeen patients had a severe reaction after Vespa Crabro sting and proved skin and CAP positive also to vespula. In 11/17 patients, Vespula germanica venom efficiently bound the also the Vespa crabro specific IgE, whereas the opposite never occurred. In 6 subjects the CAP-inhibition provided inconclusive results and their sera were analysed by immunoblotting. The SDS-PAGE procedure identified hyaluronidase, phospholipase A1 and antigen 5 as the allergens of the venoms. In 5 sera the levels of IgE against antigen 5 of Vespa crabro were higher than IgE against Vespula germanica, thus indicating a true sensitisation to crabro. CONCLUSIONS: In the case of multiple positivities to Vespa crabro and Vespula germanica the CAP inhibition easily detects the cross-reactivity. Ambiguous results at the CAP inhibition assay testified for a true sensitisation to Vespa crabro.
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J ALLERGY CLIN IMMUNOL VOLUME 123, NUMBER 2
Prevalence Of Hymenoptera Venom Allergy In 13-18 Years Old Thai Children S. Sittisomwong, MD, P. Sangsupawanich, MD, PhD; Allergy and Immunology Unit, Pediatric Department, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand. RATIONALE: Prevalence of Hymenoptera venom hypersensitivity has not been systematically estimated in Thai children. We sought to determine the prevalence of insect sting allergy among 13 -18 years old children in Hat Yai, Thailand. METHODS: A self-report insect allergy questionnaire was administered to 2,000 children age 13 -18 years across Had Yai, Thailand. Skin prick test with 4 hymenoptera allergens (honey bee, mixed wasp, yellow hornet venom and fire ant whole body extract) were convinced on all Hymenoptera-allergic subjects. Subjects with history of severe Hymenoptera allergic reaction and positive skin prick test to Hymenoptera venom were informed for the role of venom immunotherapy. RESULTS: One thousand eight hundred and forty eight questionnaires were available for analysis. Of these, 15.3% had a large local reaction (LLR), 15.4% had a mild to moderate systemic reaction (MSR), and 1.6% had a severe systemic reaction (SSR). One hundred and nine subjects underwent insect venom skin test. The positive rate of sensitization to honey bee, mixed wasp, yellow hornet and fire ant were 0.9%, 1.8%, 5.5% and 33.9%, respectively. CONCLUSIONS: This is the first prevalence survey of systemic sting reactions in Thailand which fire ant venom is the most common insect allergic sensitization among Thai teenagers.
940
The Crystal Structure of Sol i 3, a Major Fire Ant Venom Allergen D. R. Hoffman1, S. Padavattan2, M. Schmidt3, Z. Markovic’-Housley2; 1 Brody School of Medicine at East Carolina University, Greenville, NC, 2 Biozentrum, University of Basel, Basel, Switzerland, 3East Carolina University, Greenville, NC. RATIONALE: Sol i 3 is a member of the wasp antigen 5 family, but IgE antibodies from fire ant venom allergic patients do not show significant cross-reactivity with vespid wasp antigen 5’s. METHODS: Recombinant Sol i 3 was produced in baculovirus with a Cterminal hexahistidine. The carbohydrate free form was isolated by cation exchange chromatography and crystallized by hanging-drop vapor diffusion. Diffraction data were collected to 3.05 angstrom from a single crystal at the Swiss Light Source. The images were indexed and integrated using the MOSFILM program and the structure solved by molecular replacement using PHASER with the structure of Ves v 5. PROCHECK showed 90.1% of the residues within the allowed region of the Ramachandran plot. RESULTS: There were two monomers of Sol i 3 per asymmetric unit with 70% solvent content. The secondary structure is arranged in an a-b-a sandwich fold consisting of a central antiparallel b-sheet surrounded on both sides by a-helices. The overall structure is very similar to Ves v 5 with major differences in the solvent exposed loop regions including amino acid insertions. There is very limited conservation of surface chemistry and topology, supporting the observation of very limited cross-reactivity with Ves v 5. The molecular surface of Sol i 3 can accommodate four unique Sol i 3 epitope regions. CONCLUSIONS: The three-dimensional structure of Sol i 3 shows little surface conservation with Ves v 5, providing a structural basis for the observed lack of antigenic cross-reactivity.
941
Mountain Pine Beetle: A New Aero-Allergen D. F. Stark, A. H. Y. Li; UBC, Vancouver, BC, Canada. RATIONALE: This study identifies a new aero-allergen thought to be caused by the migration and aerosolization of mountain pine beetle allergens in the interior of British Columbia. The mountain pine beetle population of British Columbia has traditionally been a stable resident of the natural eco-system for many years. Recent changes in the environment and forestry practices have resulted in a mountain pine beetle epidemic and raised the question as to whether this could cause allergic sensitization. Mountain pine beetles undertake a mass annual migration flying to new food sources of pine trees to assist in its reproductive cycle. This mass migration results in the simultaneous flight of millions of mature pine beetles from the affected area in central British Columbia. METHODS: To investigate the possibility of patient sensitization with the mountain pine beetle, an allergy extract was prepared with a saline solution, filtered by a micropore filter, and stabilized with 50% glycerol. Out-patients who visited the Prince George Allergy Clinic from September 2007 to April 2008 with allergy symptoms were allergy skin tested with this pine beetle extract. A control population was used in Vancouver. RESULTS: The prevalence of pine-beetle allergic reactivity was 32% in central British Columbia and in the Vancouver area 7%. Patients were also routinely skin tested with cockroach and dust mite allergens. Results of our studies show that there was some cross-reactivity between cockroach and mountain pine beetle reactivity. CONCLUSIONS: In conclusion this is the first study identifying mountain pine beetle allergic sensitization as a new aero-allergen.
942
Cross reactivity between European Hornet and Yellow Jacket venoms. M. G. Severino1, B. Caruso2, P. Bonadonna3, D. Labardi4, D. Macchia1, P. Campi1, G. Passalacqua5; 1Allergy & Clinical Immunology Unit, Azienda Sanitaria di Firenze, Firenze, Italy, 2Laboratory of Clinical Chemistry and Haematology, Verona General Hospital, Verona, Italy, 3Allergy Service, Verona General Hospital, Verona, Italy, 4Anallergo SpA, Firenze, Italy, 5Allergy & Respiratory Diseases DIMI, Genoa University, Genoa, Italy. BACKGROUND: Cross-reactions between venoms may be responsible for multiple diagnostic positivities in hymenoptera allergy. There are few data available on the cross-reactivity among Vespula germanica and Vespa crabro, being this latter an important cause of severe reactions in some European countries. We studied by CAP-inhibition assays and immunoblotting the cross-reactivity between the two venoms. METHODS: Sera from patients with non discriminative skin/CAP positivity to both Vespula and Vespa Crabro were collected for the analyses. Inhibition assays were carried out with a CAP method, incubating the sera separately with both venoms and subsequently measuring the specific IgE to venoms themselves. Immunoblotting was performed on sera with ambiguous results at the CAP-inhibition. RESULTS: Seventeen patients had a severe reaction after Vespa Crabro sting and proved skin and CAP positive also to vespula. In 11/17 patients, Vespula germanica venom efficiently bound the also the Vespa crabro specific IgE, whereas the opposite never occurred. In 6 subjects the CAP-inhibition provided inconclusive results and their sera were analysed by immunoblotting. The SDS-PAGE procedure identified hyaluronidase, phospholipase A1 and antigen 5 as the allergens of the venoms. In 5 sera the levels of IgE against antigen 5 of Vespa crabro were higher than IgE against Vespula germanica, thus indicating a true sensitisation to crabro. CONCLUSIONS: In the case of multiple positivities to Vespa crabro and Vespula germanica the CAP inhibition easily detects the cross-reactivity. Ambiguous results at the CAP inhibition assay testified for a true sensitisation to Vespa crabro.
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939