the body's internal defence system

• antigen

• antibody

• immune system

• white blood cells

a substance that is foreign to the body and stimulates an immune response (e.g. any large molecule such as a protein)

• antigen

• antibody

• immune system

• white blood cells

refers to substances produced by the body that the immune system does not recognise as foreign, so they do not stimulate an immune response

• self

• antibody

• immune response

• non-self

refers to any substance or cell that is recognised by the immune system as being foreign and will stimulate an immune response

• antigen

• antibody

• immune response

• non-self

a glycoprotein (immunoglobulin) made by specialised lymphocytes in response to the presence of a specific antigen, each type of this molecule has a shape that is complementary to its specific antigen

• antigen

• antibody

• immune response

• plasma cell

the complex series of responses of the body to the entry of a foreign antigen, it involves the activity of lymphocytes and phagocytes

• clonal expansion

• clonal selection

• immune response

• plasma cell

individual lymphocytes have cell surface receptors specific to one antigen; this specificity is determined as lymphocytes mature and before any antigens enter the body (during an immune response the only lymphocytes to respond are those with receptors specific to antigens on the surface of the invading pathogen)

• clonal expansion

• clonal selection

• immune response

• plasma cell

the increase in number of specific clones of lymphocytes by mitosis during an immune response

• clonal expansion

• clonal selection

• immune response

• plasma cell

short-lived activated B-lymphocytes produced during clonal expansion; produce and release antibody molecules

• primary response

• memory B cell

• secondary response

• plasma cell

long-lived activated B-lymphocyte that is specific to one antigen; are activated to differentiate (develop) into plasma cells during secondary immune responses to the specific antigen

• primary response

• memory B cell

• secondary response

• plasma cell