| A | B |
|---|
| Acquired immune response | immune response to a foreign substance, based on the specific memory of a past exposure to that same foreign substance |
| Active immunity | Type of immunity based on antibodies developed in response to an antigen. There are two types of active immunity : natural and acquired |
| Allergen | Antigen producing a hypersensitivity, or allergic reaction |
| Allergy | Hypersensitivity acquired through exposure to a particular allergin that elicits an exaggerated reaction on reexposure to the same allergen |
| Anaphylaxis | Severe immediate type of hypersensitivity or allergy in which an exaggerated immunologic reaction occurs on reexposure to a foreign protein resulting in hives, itching, swelling, vascular collapse and shock. |
| Antibody | Protein molecule, an immunoglobulin, that is secreted by plasma cells and reacts with a specific antigen |
| Antibody titer | Level of a specific antibody in the blood |
| Antigen | Any substance able to induce a specific immune response |
| Attenuate | To reduce the severity of a disease or the virulence of a pathogenic agent, as is done in the development of certain vaccines |
| Autoantibody | Antibody that reacts against a normal tissue constituent of one's own body |
| Autoimmune disease | Disease characterized by tissue trauma caused by an immune response against tissue constituents of one's own body |
| Cell-mediated immunity | type of immunity in which the major role is played by T lymphocytes |
| Humoral immunity | Type if immunity in which B cell lymphocytes and the antibodies they produce as plasma cells play the predominant role |
| Hypersensitivity | Altered state of reactivity in which the body reacts to a foreign agent or allergen with an exaggerated immune response. There are 4 types of hypersensitivity Types I through IV |
| Immune complex | Combination of an antibody and antigen, producing a complex that can initiate a hypersensitivity reaction |
| Immunization | Induction of active immunity. When the pathogenic microorganism used to induce active immunity is encountered after vaccination, a stronger, faster immune response |
| Immunodeficiency | Reduced immune response resulting from hypoactivity or decreased numbers of lymphoid cells |
| Immunoglobulins | Proteins that, when secreted by plasma cells, serve as antibodies designed to respond to a specific antigen |
