Efficacy of vaccines

Question

State how the immune memory leads to efficacy of vaccines and also produces allergies?

Answer 1

Vaccines are said to have controlled inoculations of the fragments of infectious agents or of inactive infectious agents in order to induce the primary immune response, the formation of the specific memory B lymphocytes against the antigen. Thus, the organism generates the immunoglobulins and becomes prepared for destroying the antigens when it is exposed to the new infections by those agents. In allergies, humoral immune system is sensitized (forms antibodies and specific memory B lymphocytes) against some of the common environmental substances which are wrongly recognized as the antigens. Such as, dust particles, pollen-derived substances, compounds which are present within the foods or in medicines, may be recognized as the antigens triggering the primary response and thus, creating an immune memory against them which then become causes of the allergy. The more the individual is exposed to those substances the more intense becomes the immune reaction. The IgE antibodies which causes allergy bind to the receptors of leukocytes known as mastocytes whose cytoplasm is full of the histamine granules. The antibody-mastocyte bond causes these cells to release the great amount of histamine in the circulation, stimulating the inflammation and producing the allergic symptoms and signs. For this reason, allergy is treated with the help of antihistamines, drugs which block the histaminic reaction. Exacerbated allergic reactions, like, in hypersensitivity to some medicines such as penicillin and sulfas, which may cause anaphylactic shock, a severe clinical condition which sometimes leads to the death.