Question

Which one of the following antibodies play an important role as mediator in allergic response?
(a) Ig E
(b) Ig G
(c) Ig A
(d) Ig D

Answer 1

Hint: This particular antibody is responsible for hypersensitivity. It is synthesized by plasma proteins. Immunity against parasites such as helminths such as Schistosoma mansoni, Trichinella spiralis, and Fasciola hepatica is its key feature.

Complete step by step answer:
A protein that is formed in response to the antigen is an antibody. In the allergic response, IgE serves as the mediator. It is often referred to as a hypersensitivity reaction. Plasma cells synthesise it. The antibodies are bound to the mast cells in the event of an allergy. These IgE primed mast cells release histamines and cytokines during allergen exposure.
It has specific functions like:
- Parasite hypothesis
- Toxic hypothesis like allergic disease
- Cancer
So, the correct answer is ‘Ig E antibodies’.

Additional information:
Ig A: An antibody that plays a crucial role in the immune function of mucous membranes is immunoglobulin A (IgA, also known as IgA in its secretory form). In conjunction with mucosal membranes, the quantity of IgA produced is greater than all other forms of antibody combined.
Ig D: is a monomeric isotype of an antibody that is expressed in immature B-lymphocyte plasma membranes. IgD is also produced in a secreted form that is present in small amounts in serum blood. Secreted IgD consists of two delta-class heavy chains and two medium chains.
Ig G: Immunoglobulin G is an antibody type. IgG is the most common type of antibody found in the blood circulation, containing approximately 75 percent of serum antibodies in humans. Plasma B cells build and release IgG molecules. There are two antigen binding sites on each IgG.

Note: When researchers performed a multivariable cancer incidence analysis based on IgE levels, they found that a 10-fold higher IgE level conferred only a marginally higher risk of developing any cancer, but was substantially protective of developing CLL and multiple myeloma, as they suspected.