What will be the immediate action of allergen when it enters the body for a second time?
A)degranulation
B)bonding of allergen to adjacent IgE binding sites on mast cells and basophils
C)binding of IgE by the Fc region to mast cells and basophils
D)histamine acts on smooth muscle
E)prostaglandins cause vasodilation and increased vascular permeability

Question

Quizplus · Accepted Answer

When an allergen enters the body for a second time, it binds to adjacent IgE binding sites on mast cells and basophils, causing cross-linking of IgE molecules. This in turn triggers degranulation, which releases histamine and other mediators that cause the symptoms of an allergic reaction. Therefore, option B is the correct immediate action of an allergen upon second exposure.

What Will Be the Immediate Action of Allergen When It