In an immunological study investigating allergic rhinitis mechanisms, interaction between antigen-presenting cells (APCs) and T lymphocytes is examined. Upon initial allergen exposure (e.g., pollen), what is this interaction's role in initiating the allergic response?
B is correct because: Adaptive immune response initiates when APCs (e.g., dendritic cells) capture allergens, process them, and present peptides via MHC class II to CD4+ T lymphocytes, activating and differentiating them into Th2 cells secreting IL-4, IL-5, IL-13, stimulating IgE production | A incorrect: T cells don't phagocytose antigens - this is phagocyte and APC function | C incorrect: histamine released from mast cells after IgE-antigen binding, not from APCs | D incorrect: IgE produced by B cells after Th2 cell stimulation, not directly by T cells | Immunology specialist consultation indicated when: primary immunodeficiency suspected, repeated immunotherapy failure, or unexplained systemic symptoms | Modifying variable: APC deficiency or MHC class II dysfunction prevents allergic response initiation, causing immunodeficiency | Pearl: Dendritic cells in nasal mucosa function as "sentinels" - their number and activation state determine allergic response severity, thus targeted in immunotherapy | Scott Browns Otorhinolaryngology 8th edition volume 1.pdf — pp. 125, 157