antigen

any substance or organism that provokes an immune response (produces immunity) when introduced into the body

any substance that acts as an antigen to cause agglutinin production

any of several antigens that occur naturally in the fetus and sometimes in adults with cancer

a bacterial toxin that has been weakened until it is no longer toxic but is strong enough to induce the formation of antibodies and immunity to the specific disease caused by the toxin

a blood group antigen possessed by Rh-positive people; if an Rh-negative person receives a blood transfusion from an Rh-positive person it can result in hemolysis and anemia

immunogen consisting of a suspension of weakened or dead pathogenic cells injected in order to stimulate the production of antibodies

a mixture of toxin and antitoxin used to immunize against a disease

an antigen capable of causing the production of (or reacting with) an isoagglutinin

an abnormally large amount of this fetoprotein in the fetus can signal an abnormality of the neural tube (as spina bifida or anencephaly)