Question

A)

describe the four types of allergic reactions and identify which
branch of the immune system is involved in each type ?

B) name the route most likely to sentize a perion to an
allergic reaction to

Answer 1

There are four types of allergic reactions: type I, type II, type III, and type IV. Each type involves different mechanisms and branches of the immune system. Type I, II, and III hypersensitivities are mediated by antibodies, while type IV hypersensitivity is T-cell mediated.

Step-by-step explanation:

There are four types of allergic reactions:

1. Type I hypersensitivity: This type is mediated by IgE antibodies and mast cells. It involves an immediate immune response upon exposure to an allergen. Examples include food allergies, hay fever, and anaphylaxis.
2. Type II hypersensitivity: This type occurs when antibodies bind to antigens on cells, leading to cell destruction. Examples include blood transfusion reactions and autoimmune diseases like hemolytic anemia.
3. Type III hypersensitivity: In this type, immune complexes of antigens and antibodies are deposited in tissues, triggering inflammation and tissue damage. Examples include systemic lupus erythematosus and rheumatoid arthritis.
4. Type IV hypersensitivity: This type is also called delayed-type hypersensitivity (DTH) and is mediated by T cells. It involves a delayed immune response, typically occurring 24-72 hours after exposure to an allergen. Examples include contact dermatitis and tuberculin skin test reactions.

The branch of the immune system involved varies for each type. Type I, II, and III hypersensitivities are B-cell/antibody-mediated, while type IV hypersensitivity is exclusively a T-cell phenomenon.