Chapter 6: Immune System

Roberto AyalaBio 120

Initial Immune Response

Three Important Items Play Key Roles.

2. Antigens: Any foreign substance that stimulates antibody production.

● Invading substance can be biologically active, such as bacteria and viruses.

● Can be non-organic, such as chemical irritants from environment.● Can be biological by-products such as cellular waste and toxins.

4. Antibodies: Marker protein produced by the body that target foreign substances.● Antibodies made in B Lymphocytes, commonly called B-Cells.● Targets one specific type of antigen.● Binds to antigen forming antigen-antibody complex.● Can passively deactivate substance and/or mark substance for phagocytosis.

6. Phagocytosis: Destruction of foreign substances via cellular ingestion and digestion.● Phagocytes are cells capable of engulfing and digesting foreign substances.

● Macrophages are activated monocytes (a type of leukocyte) that are concentrated in areas that are high risk for foreign exposure (lungs, liver, etc).

• Commonly known as white blood cells.

● Can be subdivided into two groups:

● GranulocytesBasophiles: Least numerous, present in some inflammatory responses.

Eosinophils: Increases in allergic reactions, anti-parasitic and anti-viral defense.

Neutrophils: Most numerous in body, highly phagocytic, short lived.

2. Agranulocytes

Monocytes: Can differentiate into a macrophage for active defense or a dendritic cell which processes antigens and assists T and B Cells.

Lymphocytes: Differentiate into T-Cells , B-Cells, or Natural Killer Cells (multi-role T-Cells).

Image from: http://diverge.hunter.cuny.edu/~weigang/Images/16-05_leukocytes_1.jpg

Leukocytes

Antigens

Any foreign substance that causes the immune system to produce antibodies.

A Basic Immune Response Process:

2. A macrophage ingests a foreign substance, preserving antigen markers, incorporating these markers with proteins on their cellular surface. This is known as a MHC-antigen complex.

3. The MHC-antigen complex interacts with T-Cells. T-Cells will then rapidly divide into other both helper and killer T-Cells primed for a specific antigen. B-Cell division, with new cells made to target the antigen, will rapidly increase as well.

4. With numerous T-Cells targeting a specific antigen, T-Cells will attack any substance presenting that antigen. Neutralization can occur through phagocytocsis or though enzyme attack on cellular structures and functions.

Antibodies

Antibodies are: 2. Proteins that are used to identify and promote an

immune response.3. Specific to one type of antigen. This is called a

lock-and-key response.4. Produced by B-Cells.

The Antibody Process:7. B-Cells are produced to produce one type of

antibody that covers the cell surface.8. B-Cell activation occurs with the antibody

interacts with a known antigen.9. Upon chemical signal from T-Cells, rapid

division and differentiation occurs.10. Newly made B-Cells release numerous amounts

of antibodies into the bloodstream. 11. Targeted antigens are easily spotted by

phagocytes and other immune responses.

Sources:

Textbook:

Fremgen, Bonnie F., Suzanne S. Frucht. Medical Terminology: A Living Language

Saddle River, New Jersey: Pearson Education, Inc. 2009

Online Sources:

http://medlineplus.gov/

http://www.dimethaid.de/images/layout/Macrophage_Bacteria_rgb.jpg

http://diverge.hunter.cuny.edu/~weigang/Images/16-05_leukocytes_1.jpg

http://www.uic.edu/classes/bios/bios100/lecturesf04am/264.jpg

http://wpcontent.answers.com/wikipedia/commons/thumb/9/98/Antigen_presentation.jpg/240px-Antigen_presentation.jpg