Page 84 - The Miracle in the Immune System
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82      THE MIRACLE OF THE IMMUNE SYSTEM

              How Do The B Cells Recognise The Enemy?
              In a complete state of preparedness for war, the B
           cells then learn to discriminate the enemies from the
           body cells before defending the body.
              They do not need to expend much effort to do this,
           because these cells and the antibodies they manufacture
           are able to recognise the enemy directly from their
           shapes without any assistance. A receptor on their sur-
           face meets the antigen for which it was programmed,
           and binds to several small parts on it. Thus, the antigen
           is identified as a foreigner. In this way, B cells can easily
           recognise antigens, such as bacteria.

              What Is The Function Of B Cells?
              B cells are like guards who are always on the look-
           out for microbes. When they encounter an invader,
           they rapidly divide and start
           to produce antibodies.
           These antibodies bind to
           microbes like B cell recep-
           tors. The enemy cells that
           are marked by the antibod-
           ies as foreigners are driven
           out of the body at the end
           of the relentless struggle of
           phagocytes and T cells. By
           the time the B cells inacti-
           vate the enemy with the  AB cell covered with bacteria.
           millions of antibodies they
           have produced, they have also marked it for killer cells.
           Here, there is another important point, which is as im-
           portant as destroying and marking foreign cells. It is
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