A patient experiences acute bronchospasm, urticaria, and hypotension minutes after receiving a bee sting. This reaction is mediated primarily by the release of histamine and other mediators from mast cells and basophils due to the cross-linking of which antibody class?

The correct answer to the question "A patient experiences acute bronchospasm, urticaria, and hypotension minutes after receiving a bee sting. This reaction is mediated primarily by the release of histamine and other mediators from mast cells and basophils due to the cross-linking of which antibody class?" is Option C: IgE.

The other options — A) IgG, B) IgA, D) IgM — are incorrect for this USMLE Exam Prep question. As explained above: Type I hypersensitivity reactions, like anaphylaxis, are IgE-mediated. IgE antibodies bind to mast cells and basophils, and subsequent exposure to the antigen causes cross-linking of IgE, triggering …