Body’s organized defense mechanism against external invaders, mainly infections is the immune system. It works to find and respond to these foreign substances, which are called antigens. Antigens are substances that are adept of causing the antibodies production. Antigens can or might not lead to an allergic reaction. Certain antigens that cause a causatives allergic reaction and the production of IgE are allergens.

The immune system purpose is forces mobilization at the invasion site and destroys the enemy. One of the ways it does this is to create antibodies the protective proteins, which are precisely targeted against certain foreign substances. These antibodies, or immunoglobulins (IgG, IgM, IgA, IgD), are defensive and assist destroy a foreign particle by attaching to its surface, thus making it at ease for other immune cells to destroy it. The allergic person nevertheless, develops a particular type of antibody called immunoglobulin E, or IgE, in reaction to definite usually bland foreign substances, such as cat dander.