Download Click here to the guide.

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Document related concepts

Allergy wikipedia , lookup

Gluten immunochemistry wikipedia , lookup

Social immunity wikipedia , lookup

Rheumatic fever wikipedia , lookup

Atherosclerosis wikipedia , lookup

T cell wikipedia , lookup

Duffy antigen system wikipedia , lookup

Thymus wikipedia , lookup

ELISA wikipedia , lookup

Complement system wikipedia , lookup

Blood type wikipedia , lookup

Sjögren syndrome wikipedia , lookup

Lymphopoiesis wikipedia , lookup

DNA vaccination wikipedia , lookup

Molecular mimicry wikipedia , lookup

Anti-nuclear antibody wikipedia , lookup

Macrophage wikipedia , lookup

Antibody wikipedia , lookup

Phagocyte wikipedia , lookup

Immunocontraception wikipedia , lookup

Immune system wikipedia , lookup

Hygiene hypothesis wikipedia , lookup

Adoptive cell transfer wikipedia , lookup

Adaptive immune system wikipedia , lookup

Monoclonal antibody wikipedia , lookup

Innate immune system wikipedia , lookup

X-linked severe combined immunodeficiency wikipedia , lookup

Polyclonal B cell response wikipedia , lookup

Cancer immunotherapy wikipedia , lookup

Immunomics wikipedia , lookup

Psychoneuroimmunology wikipedia , lookup

Immunosuppressive drug wikipedia , lookup

Transcript
Composition of the Immune System
The ability of the immune system to mount a response to disease is dependent on many
complex interactions between the components of the immune system and the invading
antigens, or disease-causing agents.
Macrophages
White blood cells are the main components of the immune system. Some white blood
cells, known as macrophages, play a function in immunity by surrounding, ingesting,
and destroying invading bacteria and other foreign organisms in a process called
phagocytosis (literally, "cell eating"), which is part of the inflammatory reaction.
Macrophages also attach to invading antigens and deliver them to be destroyed by
other components of the adaptive immune system.
Lymphocytes
Lymphocytes are specialized white blood cells whose function is to identify and destroy
invading antigens. All lymphocytes begin as "stem cells" in the bone marrow, the soft
tissue that fills most bone cavities, but they mature in two different places. Some
lymphocytes mature in the bone marrow and are called B lymphocytes. B lymphocytes,
or B cells, make antibodies, which circulate through the blood and other body fluids,
binding to antigens and helping to destroy them. Other lymphocytes, called T
lymphocytes, or T cells, mature in the thymus, a small glandular organ located behind
the breastbone. Some T lymphocytes, called cytotoxic (cell-poisoning) or killer T
lymphocytes, directly destroy cells that have specific antigens on their surface that are
recognized by the killer T cells. Helper T lymphocytes, a second kind of T lymphocyte,
regulate the immune system by controlling the strength and quality of all immune
responses.
Antibodies
Antibodies are Y-shaped proteins called immunoglobulins (Ig) and are made only by B
Lymphocytes. The antibody binds to the antigen at the ends of the arms of the Y. The
area at the base of the Y determines how the antibody will destroy the antigen. This
area is used to categorize antibodies into five main classes: IgM, IgG, IgA, IgD, and IgE.
Antibodies can sometimes stop an antigen's disease-causing activities simply by
neutralization-that is, by binding the antigen and preventing it from interfering with the
cell's normal activities.
Antibodies also help destroy antigens by coating the surface of the antigens, preparing
them for ingestion by macrophages. Since macrophages have receptors that stick to the
base of the antibody's Y structure, antigens coated with antibodies are more likely to
stick to the macrophages and be ingested.
Adapted from “Blood – The River of Life,” at http://library.thinkquest.org/C0115080/?c=blood
Immune Deficiency
Deficiencies in immune function may be either inherited or acquired. Inherited immune
deficiencies usually reflect the failure of a gene important to the generation or function
of immune system components.
Some inherited diseases damage a person's innate immunity by making macrophages
incapable of ingesting or breaking down invading organisms. Individuals affected by
these diseases are especially susceptible to opportunistic infections-that is, infections
by normally harmless organisms that can flourish in a person whose immune system
has been weakened.
Adapted from “Blood – The River of Life,” at http://library.thinkquest.org/C0115080/?c=blood