Polyclonal Immunoglobulin E specific for Alternaria alternata allergens (Alt a-specific IgE)

Polyclonal IgE antibodies specific for Alternaria alternata allergens are the primary mediators of Type I hypersensitivity reactions to this ubiquitous environmental fungus. These antibodies are produced by plasma cells and circulate in the blood or bind to high-affinity FcεRI receptors on mast cells and basophils, as well as low-affinity FcεRII (CD23) on B cells and other leukocytes (Galli & Tsai, 2012). When Alternaria allergens, particularly the major allergen Alt a 1, cross-link these cell-bound IgE molecules, they trigger the immediate release of inflammatory mediators such as histamine, proteases, and cytokines, leading to clinical manifestations like allergic rhinitis and severe asthma (Gabriel et al., 2016). In B cells, membrane-bound IgE acts as a component of the B-cell receptor, facilitating allergen uptake and presentation to T cells, which further drives the Th2-biased immune response. Therapeutic interventions targeting this system include omalizumab, a monoclonal antibody that sequesters IgE to prevent its interaction with receptors, and allergen-specific immunotherapy (AIT), which utilizes Alternaria extracts to induce immunological tolerance and reduce the production of specific IgE (Bousquet et al., 2007; Pfaar et al., 2014).

Other names

Alternaria-specific IgEAnti-Alternaria IgEAlt a 1-specific IgEAlternaria-specific immunoglobulin E

Omalizumab binds to the Cε3 domain of IgE, preventing its interaction with FcεRI on mast cells and basophils, thereby inhibiting degranulation (Bousquet et al., 2007). Allergen-specific immunotherapy (AIT) uses Alternaria extracts to induce T-cell tolerance and stimulate the production of IgG4 blocking antibodies that prevent IgE-allergen binding (Pfaar et al., 2014). Quilizumab targets the M1-prime segment of membrane IgE on B cells, leading to the depletion of IgE-switched B cells and a reduction in IgE production (Gevaert et al., 2013).