A change in the structure of an
antigen on the surface of a
disease-causing
microorganism or virus (a
pathogen) so that the
host's
immune system no longer recognizes the
pathogen and must make new antibodies to recognize the changed
antigens before the
host can continue to combat the
disease. As a result, the
host cannot stay immune to the
disease.
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.