Allergen

Definition

An allergen is a typically harmless substance that triggers an exaggerated immune response, known as hypersensitivity, in susceptible individuals. Common allergens include pollen, dust mites, pet dander, and certain foods.

5 Must Know Facts For Your Next Test

1. Allergens can trigger various types of hypersensitivities, most commonly Type I (immediate) hypersensitivity.
2. Exposure to allergens leads to the production of IgE antibodies by B cells.
3. Mast cells and basophils play a crucial role in allergic responses by releasing histamines upon activation by IgE-allergen complexes.
4. Symptoms of allergic reactions can range from mild (e.g., hay fever) to severe (e.g., anaphylaxis).
5. Genetic predisposition and environmental factors both contribute to the likelihood of developing allergies.

Review Questions

• What type of antibody is primarily involved in the body's response to allergens?
• Which cells release histamines during an allergic reaction?
• Name two common symptoms associated with exposure to allergens.

Related terms

Hypersensitivity: An excessive or inappropriate immune response against antigens.

IgE Antibody: An immunoglobulin involved in allergic reactions and defense against parasitic infections.

Mast Cell: A type of white blood cell that releases histamine and other chemicals during inflammatory and allergic reactions.