Question

1. Why is it that the second exposure to an allergen, and not necessarily the first, provokes the allergic inflammatory response?

2. What role does a B plasma cell play in an allergic response? (think antibodies)

Answer 1

1.The immune system—which includes antibodies, white blood cells, mast cells, complement proteins, and other substances defends the body against foreign substances (called antigens).

In susceptible people, the immune system can overreact when exposed to certain substances (allergens) and results in an allergic reaction.

In many allergic reactions, the immune system, when first exposed to an allergen, produces a type of antibody called immunoglobulin E (IgE). IgE binds basophils in the bloodstream and to a mast cells in the tissues. The first exposure may make people sensitive to the allergen (called sensitization) but does not cause symptoms. When sensitized people subsequently encounter the allergen, the basophils and mast cells with IgE on their surface release substances such as histamine, prostaglandins, and leukotrienes that cause swelling or inflammation in the surrounding tissues. That's why second exposure to an allergre provokes the allergic inflammatory response.