The initial exposure of a person to a foreign antigen is known as ________________.

Question

Quizplus · Accepted Answer

The initial exposure to a foreign antigen sensitizes a person to future exposures. In anaphylaxis, a previously sensitized person whose mast cells are already bound by antigen-specific immunoglobulin E (IgE) may experience massive mast cell degranulation when the antigen binds to IgE. The degranulation of mast cells results in the release into the circulation of histamines, proteases, and cytokines (such as interleukins). The most common agents that bind IgE and produce anaphylaxis are hymenoptera stings, drugs (such as penicillins), and foods (such as tree nuts). Urticaria (hives) is one skin manifestation of allergic, anaphylactic, or anaphylactoid reactions.

The Initial Exposure of a Person to a Foreign Antigen