Which class of immunoglobulins sensitizes cells to allergens?

Immunoglobulins E or IgE

Explanation:

Immunoglobins E or IgE is produced by the immune system. If anyone have allergy, the immune will overreact with the allergens produces IgE antibodies. IgE Antibodies then reach to the cells responsible to release certain chemicals or mediators that produce Allergic Reaction. It is also known as type 1 Hypersensitivity.

The missing options are:

IgA

IgG

IgE

IgM

The correct answer is IgE

Explanation:

IgE is a kind of antibody that the immune system produces in the presence of an allergen, by allergen, we understood any harmless substance that the body recognizes as dangerous, so it produces immunoglobulin E.

IgA is present in secretions like saliva, IgG is present during pregnancy, and they can go through the placenta, and IgM is the first response to an antigen that our immune system produces.