Question

There are five classes of antibodies produced in humans. Which type are associated with Allergic reactions (Type I Hypersensitivity)? Which cells degranulate in response to the presence of these antibodies? What is released during the degranulation process?

Answer 1

In type 1 hypersenaitivity the B-cells are stimulated and in response IgE antibodies are released.IgE thus produced gets bound to mast cells leading to its degranulation and production of mediator chemicals to promote inflamation.Eg. In respiratory tract IgE gets bound to mast cells of respiratory lining leading to their degranulation releasing primary mediators like histamine and serotonin causing vasodilatation and bronchoconstriction and secondary mediators like leukotrienes and prostaglandins causing inflamatory cell infiltration.