immune response

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An integrated bodily response to an antigen, especially one mediated by lymphocytes and involving recognition of antigens by specific antibodies or previously sensitized lymphocytes.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun immunology The body's integrated response to an antigen, mediated by lymphocytes.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a bodily defense reaction that recognizes an invading substance (an antigen: such as a virus or fungus or bacteria or transplanted organ) and produces antibodies specific against that antigen