Question

Explain the principle of immunization.

Answer 1

Hint: Immunization is the process in which a vaccine is administered in a person's body and the person is made immune or resistant to an infectious disease. Vaccines stimulate and strengthen the body's immune system to protect the person against subsequent infection or disease.

Complete answer:
In this question we have asked the principle of immunization. So, first of all what is Immunization.
According to WHO, Immunization is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine. Vaccines stimulate the body’s own immune system to protect the person against subsequent infection or disease. To produce an immune response, live, attenuated organisms which cause the disease are inserted into the person's body. A small dose of administered virus or bacteria replicates in the body and produces enough organism that our immune system activates against that virus or bacteria to kill it. As the inserted organism is attenuated, it can not cause any disease in that person. When our immune system activates, it makes antibodies against that bacteria or virus and kills them. Now, antibodies against that particular organism are already present in the body. When that organism will actually attack, antibodies which are already present in the body will kill that organism and disease will not occur. This is the principle of immunization which is given by Edward Jenner.

Note: We can also write about active and passive immunization. In passive immunization, direct antibodies are inserted into the person's body and in active immunization live, attenuated organism is inserted and the person's body itself forms the antibodies.