Related Words

Antigen: A foreign substance that causes the body to produce antibodies.

Antigen Drift: The random accumulation of mutations in viral genes recognized by the immune system. Such accumulation may significantly change the antigens of the virus, and may help it evade the immune system.

Antigenic Determinant: The site on an antigen to which an antibody binds, forming an antigen-antibody complex.

Antigens: Molecules carried or produced by microorganisms that initiate antibody production; mostly proteins or proteins combined with polysaccharides.

Biologics: Immunization vaccines, bacterins, antigens, and antitoxins and other preparations made from living organisms and their products, intended for use in diagnosing, immunizing, or treating human . . . View Full Definition

Secondary Immunity: Resistance to an antigen the second time it appears. Because of the presence of B and T memory cells produced during the first exposure to the antigen, the second response is faster and more . . . View Full Definition

Veterinary Biologics: Vaccines, antigens, antitoxins and other preparations made from living organisms (or genetically engineered) and intended for use in diagnosing, treating, or immunizing animals. Unlike some . . . View Full Definition

Helper T Cells: A type of lymphocyte that stimulates the production of antibodies by activating B cells when an antigen is present.

B Cells: Type of lymphocyte responsible for antibody-mediated immunity; mature in the bone marrow and circulate in the circulatory and lymph systems where they transform into antibody-producing plasm . . . View Full Definition

Anaphylaxis: A severe allergic reaction in which histamine is released into the circulatory system; occurs upon subsequent exposure to a particular antigen; also called anaphylactic shock.