1 1.Component of immune system center immune organs: bone marrow, thymus Immune organs peripheral immune organs: spleen, lymph nodes, skin ， mucous membrane.

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1.Component of immune system

center immune organs: bone marrow, thymus

Immune organs

peripheral immune organs: spleen, lymph nodes, skin ，

mucous membrane

Immunocytes: T lymphocyte, B lymphocyte, macrophage, natural killer etc

immune molecules: antibody, cytokines (tumor necrosis factor, interferon

interleukin etc), complement （补体）

Immune systemImmune system

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2. Antigen 2.1 Definition: An antigen is any substance that

causes your immune system to produce antibodies against it. An antigen may be a foreign substance from the environment such as chemicals, bacteria, viruses, or pollen. An antigen may also be formed within the body, as with bacterial toxins or tissue cells

2.2 What kind of substances can be identified as antigen by immune system?

① Foreign substance ② Large molecules with certain chemical

composition and structure. ③ Integrity

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2.3 Complete antigen and hapten Complete antigen: an antigen capable of

stimulating immune system to produce antibody and binding with the antibiody.

Hapten: a hapten is a small molecule which can elicit an immune response(to stimulate the production of antibody) only when it is attached to a larger carrier such as a protein.

2.4 Antigen determinant: The site on the surface of an antigen molecule which binds to an antibody. Different antigen has different antigenic determinant and can stimulate the production of different antibody.

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3.3.AntibodyAntibody

3.1 Definition: Antibodies are immune 3.1 Definition: Antibodies are immune system-related system-related immunoglobulinsimmunoglobulins that are that are found in blood or other bodily fluids of found in blood or other bodily fluids of vertebratesvertebrates, and are used to identify and , and are used to identify and neutralize foreign objects, such as bacteria neutralize foreign objects, such as bacteria and viruses. Antibodies can bind very and viruses. Antibodies can bind very tightly to their targets (antigen) to tightly to their targets (antigen) to inactivate them.inactivate them.

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3.2 structure3.2 structure

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3.3 Production3.3 Production Antibodies are madeAntibodies are made by a class of white blood by a class of white blood

cells, called B cells, called B lymphocyteslymphocytes. Each . Each resting B cell carries resting B cell carries different membrane different membrane bound bound receptorsreceptors to to recognize a specific recognize a specific antigen. When antigen antigen. When antigen binds to this receptor, the binds to this receptor, the B cell is stimulated to B cell is stimulated to divide into divide into plasma cellsplasma cells

（浆细胞）（浆细胞） which is which is capable of producing capable of producing large amount of the same large amount of the same antibody in a soluble antibody in a soluble form.form.

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B cells can B cells can alsoalso form form memory cells memory cells that remember that remember the same the same pathogenpathogen for for faster antibody faster antibody production in production in future future infections. infections.

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4. Important 4. Important immunocytes4.1 T lymphocyte: T cells originate in the bone

marrow, mature in the thymus, and travel in the blood to other lymphoid tissues, such as the spleen, tonsils, and lymph nodes. Through receptor molecules on their surfaces, T cells directly attack invaders (antigens) by binding to them and helping remove them from the body . .

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4.2 4.2 MacrophageMacrophage: Macrophages are white blood : Macrophages are white blood cells that crawl around in the extracellular cells that crawl around in the extracellular fluids of your body and gobble up microbes fluids of your body and gobble up microbes and other foreign material. They ingest these and other foreign material. They ingest these microbes by microbes by phagocytosisphagocytosis ("cell eating"). ("cell eating").

a. Ingestion,a phagosome is formed b. The fusion of lysosomes with the phagosome, the pathogen is broken down by enzymes c. Waste material is expelled or assimilated Parts:1. Pathogens 2. Phagosome3. Lysosomes （溶酶体） 4. Waste material5. Cytoplasm6. Cell membrane

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4.3 4.3 Natural killer cellNatural killer cell NK cells are cytotoxic; small granules in NK cells are cytotoxic; small granules in

their cytoplasm contain proteins such as their cytoplasm contain proteins such as perforin(perforin( 穿孔素穿孔素 )) and proteases known as and proteases known as granzymesgranzymes （粒酶（粒酶）） . Upon release in close . Upon release in close proximity to a cell slated for killing, perforin proximity to a cell slated for killing, perforin forms pores in the cell membrane of the target forms pores in the cell membrane of the target cell, creating an aqueous channel through cell, creating an aqueous channel through which the granzymes and associated molecules which the granzymes and associated molecules can enter, inducing eithercan enter, inducing either apoptosis apoptosis （凋亡）（凋亡） or cell lysisor cell lysis （溶解）。 （溶解）。

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5.Pathology5.Pathology5.1 5.1 autoantibodyautoantibody & & autoimmuneautoimmune disease: disease: Antibodies are normally produced in response Antibodies are normally produced in response

to a foreign protein or substance within the body, to a foreign protein or substance within the body, typically a pathogen (infectious organism). typically a pathogen (infectious organism). Normally, the immune system is able to recognize Normally, the immune system is able to recognize and ignore the body's own cells.and ignore the body's own cells.

Sometimes, however, the immune system Sometimes, however, the immune system ceases to recognize one or more of the body‘s ceases to recognize one or more of the body‘s normal constituents as “self,” leading to production normal constituents as “self,” leading to production of autoantibodies. These autoantibodies attack the of autoantibodies. These autoantibodies attack the body’s own cells, tissues, and/or organs, causing body’s own cells, tissues, and/or organs, causing inflammation and damageinflammation and damage 。。

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5.2 Immunodeficiency disorders5.2 Immunodeficiency disorders are a group of are a group of disorders in which part of the immune system disorders in which part of the immune system is missing or defective. Therefore, the body's is missing or defective. Therefore, the body's ability to fight infections is impaired. ability to fight infections is impaired.

primary immunodeficiency disorders:primary immunodeficiency disorders: caused caused by inherited defects in the cells and other by inherited defects in the cells and other components of our immune system. components of our immune system.

secondary (acquired) immunodeficiency secondary (acquired) immunodeficiency disordersdisorders :caused by particular external :caused by particular external processes or diseases, such as malnutrition, processes or diseases, such as malnutrition, aging, particular medications and chronic aging, particular medications and chronic infection.infection.

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immun/o: immuneimmun/o: immune

ImmunologyImmunology ， ， Immunodeficiency diseaseImmunodeficiency disease

ImmunoglobinImmunoglobin lymph/o: lymphlymph/o: lymph splen/o: spleensplen/o: spleen tonsill/o: tonsiltonsill/o: tonsil plasm/o: plasmaplasm/o: plasma

neoplasma : tumorneoplasma : tumor

cytoplasm cytoplasm

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thym/othym/o ：： thymusthymus phag/o: eat, engulfphag/o: eat, engulf hapt/ohapt/o: attach, touch: attach, touch

hapticshaptics: sense of touch: sense of touch