Preksha Dhyana Human Body Part 2

Author(s): Jethalal S Zaveri
Publisher: Jain Vishva Bharati

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killed off by T-Cells. Thus an efficient surveillance by TCells is an important defence against cancer and other diseases caused by antigens. While T-Cells travel through the body (most of the circulating lymphocytes are T-Cells) and exert effect locally, B-Cells remain in the lymph-nodes and the synthesized antibodies are sent out through the bloodstream to the site where they are needed.
Antibodies fight invading microbes in several ways, e.g. they prevent viruses from attacking to the host cell-membranes and thus prevent them from multiplying.
Immunity
We can have a life-time protection against many diseases by developing active immunity, either stimulated by an actual attack or provoked by vaccines. Vaccines have dramatically changed our lives. The control of small-pox through vaccines has been so successful that this disease has finally disappeared entirely from the face of the earth. Many doctors never see a single case of diphtheria which was a major childhoodkiller before vaccines. Emergency protection provided by an injection of antibodies that someone else has produced against the disease, is called passive immunity. In such cases, it is wise to obtain a vaccination to develop active immunity after the emergency is over, because the introduced antibodies are rapidly lost from the body.
The antibodies that are transferred to the fetus and then to the infant, through its mother's milk confer passive immunity to any disease for which the mother possesses antibodies, and provide valuable protection during the time when the infant's own immunity system is not yet functioning effectively.
Autoimmune Diseases
The body is constantly at war. Its defenders are dedicated to the task of killing all foreign invaders. But some
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