A&P Immune System Practice Test 2026 – Complete Exam Prep

The immunoglobulin primarily responsible for allergic reactions and responses to parasitic infections is IgE. This antibody plays a crucial role in the immune system's defense against environmental allergens such as pollen, pet dander, and certain foods. When an allergen is encountered, IgE antibodies bind to it and trigger the release of histamine and other inflammatory mediators from mast cells and basophils. This response leads to the symptoms commonly associated with allergies, such as itching, swelling, and respiratory issues.

In addition to its role in allergies, IgE is also vital in defending against parasitic infections, particularly helminths (worms). The binding of IgE to parasites activates the immune system and recruits other immune cells to combat the invaders, highlighting its significance in protecting the body from certain threats.

The other immunoglobulins mentioned serve different roles: IgA is primarily found in mucosal areas and is crucial for mucosal immunity; IgM is the first antibody produced in response to an infection and primarily involved in the initial stages of immune response; and IgG is the most abundant antibody in circulation and plays a vital role in the secondary immune response and long-term immunity. While these antibodies are essential for various immune functions, none are specifically tailored