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The latex allergen Hev b 5 is a multivalent antigen
J ALLERGY CLIN IMMUNOL VOLUME 113, NUMBER 2
The Latex Allergen Hev b 5 Is a Multivalent Antigen
D. H. Beezhold1, V. L. Hickey2, M. F. Sutherland3, R. E. O’Hehir3; 1NIOSH, Morgantown, WV, 2Guthrie Research Institute, Sayre, PA, 3Alfred Hospital/Monash University, Melbourne, AUSTRALIA. RATIONALE: To gain an understanding as to why Hev b 5 is such a potent allergen, we characterized the epitopes for three monoclonal antibodies to Hev b 5. METHODS: The monoclonal antibodies included 2 IgG1 (6A10, 3G3) and 1 IgG 2b (6F6) isotypes. We used SPOTscan analysis with overlapping peptides to identify the binding regions for the monoclonals and then alanine substitution analysis to further define the critical amino acids in each epitope. Site directed mutagenesis was used to selectively eliminate the IgG binding for each epitope and single and multiple mutations were expressed as recombinant GST fusion proteins. Antibody recognition of the fusion proteins was determined by inhibition ELISA assay. RESULTS: All three monoclonal antibodies recognized the same AA sequence by SPOTs analysis and slight variations of this epitope are repeated 3 times within the Hev b 5 sequence; 63APETEK68, 120PAEGEK125, and 126PAEEEK131. Sequential alanine substitution by SPOTsalogue identified K68, E122, K131 as critical AAs in each epitope and they were changed to alanine by site directed mutagenesis.Inhibition ELISA with the mutant proteins indicated that the AA126-131 epitope was the dominant epitope but mutation of the AA120-125 epitope was required to eliminate MAb reactivity to Hev b 5. The antibodies did not appear to recognize the AA63-68 epitope in the recombinant fusion protein. CONCLUSIONS: We have identified an immunodominant epitope in Hev b 5 that is repeated 3 times within the sequence making Hev b 5 a multivalent protein. Multivalent epitopes may help to explain the potent nature of this allergen. Funding: Self-funded
MONDAY
797
Abstracts S225
The Latex Allergen Hev b 5 Is a Multivalent Antigen
D. H. Beezhold1, V. L. Hickey2, M. F. Sutherland3, R. E. O’Hehir3; 1NIOSH, Morgantown, WV, 2Guthrie Research Institute, Sayre, PA, 3Alfred Hospital/Monash University, Melbourne, AUSTRALIA. RATIONALE: To gain an understanding as to why Hev b 5 is such a potent allergen, we characterized the epitopes for three monoclonal antibodies to Hev b 5. METHODS: The monoclonal antibodies included 2 IgG1 (6A10, 3G3) and 1 IgG 2b (6F6) isotypes. We used SPOTscan analysis with overlapping peptides to identify the binding regions for the monoclonals and then alanine substitution analysis to further define the critical amino acids in each epitope. Site directed mutagenesis was used to selectively eliminate the IgG binding for each epitope and single and multiple mutations were expressed as recombinant GST fusion proteins. Antibody recognition of the fusion proteins was determined by inhibition ELISA assay. RESULTS: All three monoclonal antibodies recognized the same AA sequence by SPOTs analysis and slight variations of this epitope are repeated 3 times within the Hev b 5 sequence; 63APETEK68, 120PAEGEK125, and 126PAEEEK131. Sequential alanine substitution by SPOTsalogue identified K68, E122, K131 as critical AAs in each epitope and they were changed to alanine by site directed mutagenesis.Inhibition ELISA with the mutant proteins indicated that the AA126-131 epitope was the dominant epitope but mutation of the AA120-125 epitope was required to eliminate MAb reactivity to Hev b 5. The antibodies did not appear to recognize the AA63-68 epitope in the recombinant fusion protein. CONCLUSIONS: We have identified an immunodominant epitope in Hev b 5 that is repeated 3 times within the sequence making Hev b 5 a multivalent protein. Multivalent epitopes may help to explain the potent nature of this allergen. Funding: Self-funded
MONDAY
797
Abstracts S225