Antigen
* ALL antigens have at least ONE epitope.
* Many antigens become airborne during dental procedures.
* Most antigen induces immune responses
  - stimulates development
* Some antigen causes allergies.
* Some antigen is produced by adult hookworms
* Some antigen releases into sea water
  - stimulates immune responses
  - tests use polymerase chain reaction
* Some antigens are serums
  - unique to lymphoma cells.
  * are always 'foreign' and trigger an attack. The system is normally tolerant of its own molecules, which don't start an attack. Autoimmune diseases are caused when this safeguard fails
* activate specific lymphocytes.
  - an essential element in the development of powerful, targeted cancer vaccines
* are any of a variety of substances that the body 'sees' as foreign
  - substance that binds specifically to an antibody or a T-cell receptor
* are any substances that elicit the adaptive immune response
  - evoke responses from a person's immune system
  - chemical structures attached to the surfaces of red blood cells
  - commonly proteins, or more specifically small parts of proteins
* are either whole microorganisms, or they can be a portion of an organism or virus
  - can be part of an organism or virus
  - foreign molecules or non-self
* are generally of high molecular weight and are commonly proteins or polysaccharides
  - proteins and other large organic molecules
  - macromolecules that elicit an immune response in the body
  - markers on cells that act as microscopic flags
* are molecules or parts of molecules that are usually large, complex, and foreign
  - sported by tumor cells that advertise they are abnormal
  - pieces of the virus, which cause the immune system to react and produce antibodies
  - proteinlike substances that identify living matter, much like biochemical name tags
* are proteins foreign to the body
  - in the parasites that cause horses to produce antibodies in their blood
  - normally present in the body and ignored by the immune system
  - specific to each particular microorganism
* are substances that cause a blood or tissue reaction
  - reaction in blood or tissues
* are substances that stimulate cells to produce antibodies
  - the immune system to produce antibodies for fighting disease
  - the body senses as foreign
  - which provoke an immune system into wanting to eliminate it from the body
  - surface molecules on a cell
  - the bodies' natural way to fight off disease
  - toxins or enzymes that the immune systems considers foreign
  - usually proteins that are foreign to the body
* can be any molecule that causes antibody production
  - germs, viruses, pollens, or even cells from another person
  - proteins, carbohydrates, nucleic acids, hormones, or other substances
  - viruses, bacteria, proteins or other foreign compounds
* cause the formation of antibodies whose job it is to fight off the invading substance.
* differ vastly in their response to fixation, dehydration and embedding.
* have determinants called epitopes
  - diverse functions in viral replication
* is antigen
  - people
* prompt the body to produce antibodies.
* triggers production.
* usually appear within a few weeks of infection and disappear within a few months.
+ Lymphocyte, Types, T and B cells: Cell biology :: Immunology :: Blood cells
  * The function of T cells and B cells is to recognize foreign antigens. Antigens are surface molecules on a cell. Once they have identified an invader, the cells respond to remove pathogens or pathogen-infected cells.

### antigen:

Immunogen
* ALL immunogens are antigens.
* Most immunogens have several, overlapping epitopes.