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Antibody Variable Regions


Mammals have antibodies that respond to specific antigens. Each antibody, produced by B cells, is composed of a constant region (common to all antibodies in a particular individual) and a variable region (which binds specifically to an antigen). The variable section of an antibody is produced through random recombination events, resulting in many different types of antibodies that can each bind to different antigens.

If one of these events results in new antibodies with variable regions that match proteins common on the outside of an individual's body cells, which of the following could result?


The individual would develop an autoimmune reaction when the antibodies attached to his body cells.


The individual would develop opportunistic infections, because he would be unable to make new antibodies to fight off disease causing organisms.


The antibodies would trigger the production of more red blood cells to allow faster healing.


The antibodies would prevent the correct distribution of DNA in new body cells, causing errors in cell division.