LIFE SCIENCE

Detailed explanation-1: -Antigen-specific IgE production, with subsequent fixation of IgE to FcRI receptors on mast cells and basophils, is central to the initiation and propagation of immediate hypersensitivity reactions.

Detailed explanation-2: -The high-affinity IgE receptor, also known as FcRI, or Fc epsilon RI, is the high-affinity receptor for the Fc region of immunoglobulin E (IgE), an antibody isotype involved in the allergy disorder and parasites immunity. FcRI is a tetrameric receptor complex that binds Fc portion of the heavy chain of IgE.

Detailed explanation-3: -Allergic reactions are triggered when allergens cross-link preformed IgE bound to the high-affinity receptor FcRI on mast cells. Mast cells line the body surfaces and serve to alert the immune system to local infection.

Detailed explanation-4: -Symptoms of allergies occur after the activation of mast cells or basophils. Theoretically, the degranulation of mast cells and basophils is the definitive event in allergy, whereas IgE only serves as one of the key messengers.