Design of a heterotetravalent synthetic allergen that reflects epitope heterogeneity and IgE antibody variability to study mast cell degranulation.
The present paper describes the design of a HtTA (heterotetravalent allergen) as a multi-component experimental system that enables an integrative approach to study mast cell degranulation. The HtTA design allows presentation of two distinct haptens, each with a valency of 2, thereby better reflecting the complexity of natural allergens by displaying epitope heterogeneity and IgE antibody variability. Using the HtTA design, synthetic allergens HtTA-1 and HtTA-2 were synthesized to model a combination of epitope/IgE affinities. HtTA-1 presented DNP (2,4-dinitrophenyl) and dansyl haptens (Kd=22 and 54 nM for IgEDNP and IgEdansyl respectively) and HtTA-2 presented dansyl and the weak-affinity DNP-Pro (DNP-proline) haptens (Kd=550 nM for IgEDNP). Both HtTAs effectively induced degranulation when mast cells were primed with both IgEDNP and IgEdansyl antibodies. Interestingly tetravalent DNP-Pro or bivalent dansyl were insufficient in stimulating a degranulation response, illustrating the significance of valency, affinity and synergy in allergen-IgE interactions. Importantly, maximum degranulation with both HtTA-1 and HtTA-2 was observed when only 50% of the mast cell-bound IgEs were hapten-specific (25% IgEdansyl and 25% IgEDNP). Taken together, results of the present study establish the HtTA system as a physiologically relevant experimental model and demonstrates its utility in elucidating critical mechanisms of mast cell degranulation.
Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, U.S.A.
Michael W
MW
Handlogten
Tanyel
T
Kiziltepe
Basar
B
Bilgicer
D000485:Allergens / Q000737:chemistry / Q000276:immunology* / Q000502:physiology; D000818:Animals; D015550:Cell Degranulation / Q000187:drug effects / Q000502:physiology*; D015195:Drug Design; D000939:Epitopes / Q000737:chemistry* / Q000276:immunology*; D018740:Genetic Heterogeneity; D007073:Immunoglobulin E / Q000096:biosynthesis* / Q000737:chemistry; D008407:Mast Cells / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*; D051381:Rats
D000485:Allergens; D000939:Epitopes; D007073:Immunoglobulin E