Unformatted text preview: CELLS AND HUMORAL (ANTIBODY-MEDIATED) IMMUNITY It could be said that the antigen SELECTS the lymphocyte that responds this way, and the process is called clonal selection. It is believed that we are all prepared to respond to as many as 100 million different antigens, which means that we have that many different types of B cells, probably just a few specific to each antigen, waiting for it to come along. Activated B cells which have differentiated into plasma cells begin to secrete large numbers of antibody molecules, living only a few days but producing as many as 2000 antibody molecules per second while active. A few B cells of the clone do not become active plasma cells, but instead become memory B cells which can recognize and respond to the same antigen if it comes along again, producing antibodies much faster and more effectively with a subsequent encounter,...
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- Fall '09