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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Allergens, Antigen-Presenting Cells, Antigens, Plant, Bacterial Proteins, Betula, Cell Line, Humans, Hypersensitivity, Immunoglobulin E, Lymphocyte Activation, Monosaccharide Transport Proteins, Pollen, Recombinant Fusion Proteins, T-Lymphocytes.
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Is natural self-assembly of allergen-S-layer fusion proteins no prerequisite for reduced allergenicity and T cell stimulatory capacity? Context: Recombinant allergen-S-layer fusion proteins display a strongly reduced IgE-binding activity and promote the induction of allergen-specific Th0/1 cells and regulatory T cells. Such fusion proteins show a natural capacity to self-assemble into mono- or double-layer sheets reaching particle-like dimensions of 0.5-2 microm. We were interested in finding out whether self-assembly was crucial for the immunological characteristics of allergen-S-layer fusion proteins. The IgE-binding and mediator-releasing capacities of nonassembled and self-assembled rSbpA-Bet v 1, consisting of the major birch pollen allergen Bet v 1 and the S-layer protein SbpA, were compared in inhibition ELISA and basophil activation assays using sera from patients allergic to birch pollen. T cell stimulation was evaluated using Bet v 1-specific T cell clones reactive to distinct epitopes of Bet v 1. Autologous B lymphocytes, monocytes and monocyte-derived dendritic cells were employed to evaluate potential differences in uptake and processing by different antigen-presenting cells. Both rSbpA-Bet v 1 variants showed significantly less IgE-binding and mediator-releasing activity than Bet v 1. However, self-assembly further minimized the reduced allergenicity of nonassembled rSbpA-Bet v 1. Both rSbpA-Bet v 1 variants induced comparable proliferation in Bet v 1-specific T cell clones. B cells inappropriately presented either variant of rSbpA-Bet v 1. Self-assembly amplified the T cell stimulatory capacity of monocytes and dendritic cells.
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The promising characteristics of allergen-S-layer fusion proteins regarding their potential use for allergy treatment do not depend on the formation of particle-like structures. Final Decision: yes