Microbiology (Immune System)

Cytotoxic T-cell

(Sometimes called killer cells) help rid your body of cells that have been infected by viruses as well as cells that have been transformed by cancer but have not yet adapted to engage the immune detection system. They are also responsible for the rejection of tissue and organ grafts. Contains granules filled with potent chemicals. Binds their targets, aim their weapons, and deliver bursts of lethal chemicals. To attack, they need to recognize a specific antigen bound to self-MHC markers, whereas natural killer cells with recognize and attack cells lacking these. This gives NK cells the potential to attack many types of foreign cells.

IgA

A doublet--guards the entrance to the body. It concentrates in body fluids such as tears, saliva, and secretions of the respiratory and gastrointestinal tracts.

Antigen (non-self)

Any non-self substance of triggering an immune system response. Can be a whole non-self cell, bacterium, virus, an MHC marker protein or even a portion a protein from a foreign organism.

Interferons

Are naturally occurring cytokines that many boost the immune systems's ability to recognize cancer as a foreign invader.

Complement system

Consists of a series of about 25 proteins that work to "complement" the wokrk of antibodies in destroying bacteria. Helps get rid of the body of antigen-antibody complexes. These proteins are the culprits that cause blood vessels to become dilated and leaky, causing redness and swelling during an inflammatory response. Circulate in the blood in an inactive from. Is set off when the first complement molecule, C1, encounters antibody bound to antigen in an antigen-antibody complex.Acting, in turn, on the molecule next in line. The end product is a cylinder that punctures the cell membrane, and, by allowing fluids and molecules to flow in and out, rooms the target cell.

Myeloid progenitors

Develop into the cells that respond early and nonspecificly to infection.

Lymphoid precursors

Develop into the small white blood cells called lymphocytes. Lymphocytes respond later in infection.

Cytokines

Diverse and potent chemical messengers secreted by the cells of your immune system. They are the chief communication signals of your T Cells. They include interluekins, growth factors, and interferons. Recruit many other cells and substances to the filed of action. They encourage cell growth, promote cell activation, direct cellular traffic, and destroy target cells, including cancer cells.

Antibody shape

Each antibody is made up of two identical heavy chains and two identical light chains, shaped to form a Y.

Self-markers

Every cell in your body carries the same set of distinctive surface proteins that distinguish you as "this". Normally your immune cells do not attack your own body tissues, which carry the same pattern of self-markers, rather your immune system coextensive peaceably with your other body cells know in a state know as "self-tolerance".

Spleen

Is a flattened organ at the upper left of the abdomen. Like lymph nodes, this contains specialized compartments where immune cells gather and comfront antigens.

IgD

Is almost exclusively found inserted into the membrain of B cells, where it somehow regulates the cell's activition.

IgE

Is normally present in only trace amounts, but it is responsible for the symptoms of allergy.

Non-self markers

Molecules on the surface of foreign or abnormal cells or particles that identify the particle

MHC

Proteins serve as a recognizable scaffold that presents pieces (peptides) of forgein protein (antigenic) to immune cells. Also known as "tissue type" or human leukocyte antigens (HLA) when a patients white blood cells are becoming characterized. Class I: humans bear 6 markers out of 200 possible variations Class II: humans display 8 our of about 230 possibilities

IgG

The MAJOR immunoglobulin in the blood, is also able to enter tissue spaces; it works efficiently to coat mircroorganisms, speeding their destructing by other cells in the immune system.

Self vs non-self

The antigens on your own cells are known as self-antigens, while those that do not originate in your body are called non-self antigens. Immune cells called lymphocytes recognize non-self antigens and produce antibodies that bind specifically to each antigen.

Epitopes

The distinctive markers on antigens that trigger an immune system. When tissues or cells from another individual enter your body carrying such antigenic non-self "blank", your immune system cells react. Explains why transplanted tissues may be rejected as froegein and why antibodies bind to them.

Variable region

The sections that make up the tips of the Y's arms vary greatly from one antibody to another. IT is these unique contours in the antigen-binding site that allow the antibody to recognize a matching antigen, much as a lock matches a key.

Bone Marrow

The soft tissue in the hollow center of bones, is the ultimate source of all blood cells, including immune cells. Cells destined to become immune cells, like all blood cells, arise from "blank" from stem cells. Some develop into myeloid progenitors cells while others become lymphoid progenitor cells.

Constant region

The system of Y links the antibody to other participants in the immune defenses. This area is identical in all antibodies of the same class, for instance, all IeGs-- and is called this.

IgM

Usually combines in star-shaped clusters. It tends to remain in the bloodstream, where it is very effecting in kill bacteria.

Memory cells

Whenever T cells or B cells are activated they become "blank" cells. The next time that an individual encounters that same antigen, the immune system is primed to destroy it quickly. This is active immunity because the body's immune system prepares itself for future challenges. a long-lived lymphocyte capable of responding to a particular antigen on its reintroduction, long after the exposure that prompted its production.

Antibodies

a blood protein produced in response to and counteracting a specific antigen. "Blank" combine chemically with substances that the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood. Belong to a family of large protein molecules known as immunoglobulins.

Macrophages

a large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection. Are versatile cells; besides acting as phaocytic scavengers, they secrete a wide variety of signaling cytokines (called monokines) that are vital to the immune response. Reside in connective tissue, along digestive tract, lungs, and in spleen, even along blood vessels in the liver.

B-cells

a lymphocyte not processed by the thymus gland, and responsible for producing antibodies. Turns into a plasma cell that produces and releases into the bloodstream of thousands of specific antiobodies. 10 million copies an hour*

T-cells (Helper)

a lymphocyte of a type produced or processed by the thymus gland and actively participating in the immune response. Coordinate the entire immune response and eliminate the bruises hiding in infected cells. Your body can then produce the most effective weapons against the invaders, which may be bacteria, viruses or parasites. Other types of "blank" recognise and kill virus-infected cells directly. Some help B-cells to make antibodies, which circulate and bind to antigens. Contribute to your immune defenses in two ways. Some help regulated the complex of the overall immune response, while others are cytotoxic and directly contact infected cells and destroy them.

Stem cells

an undifferentiated cell of a multicellular organism that is capable of giving rise to indefinitely more cells of the same type, and from which certain other kinds of cell arise by differentiation.

Plasma cell

are white blood cells that secrete large volumes of antibodies. They are transported by the blood plasma and the lymphatic system. originate in the bone marrow; B cells differentiate into plasma cells that produce antibody molecules closely modelled after the receptors of the precursor B cell. Once released into the blood and lymph, these antibody molecules bind to the target antigen (foreign substance) and initiate its neutralization or destruction.

Thymus

is an organ that lies behind the breastbone; lymphocytes known as T lymphocytes, or just T cells, mature there.

Regulatory T-cells

known as suppressor T cells, are a subpopulation of T cells that modulate the immune system, maintain tolerance to self-antigens, and prevent autoimmune disease.