Which antibody is primarily responsible for protecting against parasitic worms?

IgE is the antibody primarily responsible for protecting against parasitic worms, also known as helminths. It plays a crucial role in the immune response to these large multicellular parasites. When an individual is infected with parasitic worms, IgE levels increase significantly. This antibody binds to surface receptors on mast cells and basophils. When the allergen or parasite is encountered again, the IgE antibodies trigger these cells to release histamines and other inflammatory mediators, leading to an inflammatory response that helps expel the parasites from the body.

While other immunoglobulin classes such as IgG and IgM are involved in the immune response, they are not specifically tailored for combatting parasitic infections. IgG is more associated with bacterial and viral infections, providing long-term immunity, and IgM is the first antibody produced during an immune response but is not specific for worms. IgD has a more unclear role and is primarily found on the surface of immature B cells and not prominently involved in the responses to parasitic infections. Thus, IgE is distinctly recognized for its function in defending against helminthic infections.