Alexa Fluor® 647 Mouse Anti-Human IgE Antibody (S-2853)

IgE is an antibody isotype that, despite being the least abundant in serum, sits at the epicenter of type I hypersensitivity and anti-parasite immunity; generated by plasma cells in mucosal tissues, it binds with picomolar affinity to the tetrameric FcεRI on mast cells and basophils, priming them for rapid degranulation upon subsequent allergen encounter, thereby unleashing histamine, leukotrienes and cytokines that produce the clinical spectrum from urticaria to anaphylaxis, while also orchestrating eosinophil and macrophage responses against helminths; its half-life in plasma is brief (~2 days), yet it can remain cell-bound for weeks, and its levels are tightly regulated by IL-4, IL-13 and CD40L-mediated class-switching.