1. THE IMMUNE SYSTEM Barriers Pathogens and antigens Immune system cells
Innate and adaptative response
Humoral and cellular response
Active and passive immunity
Vaccines
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2. Lines of defense
PRIMARY: intact skin, ciliated epithelium in airways, stomach acid, body fluids (tears, saliva), reflexes (ej. tos)
SECONDARY: mucous surfaces, native bacterial flora, inflammation, fever, phagocytosis, NK, macrophages
TERTIARY: B and T lymphocytes + antibodies (proteins)
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3. A pathogen or ethiological agent is any entity that causes a disease.
Examples:
Viruses
Bacteria
Protozoa
Worms
Fungi
PATHOGENS
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4. ANTIGENS Present on the surface of cells or viruses.
An antigen is any molecule recognised as non self, and capable of triggering an immune response.
Present on the surface of cells or viruses.
Examples of antigens:
Proteins
Glycoproteins
DNA or RNA
Lipids
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5. Main organs of the immune system
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6. Where are all the blood cells made?
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7. Self and non-self What does the immune system recognise?
Every cell has a set of specific proteins called the MHC (Major Histocompatibility Complex) that marks that cell’s identity. Important in transplants.
These MHC proteins recognise and activate the processing of foreign antigens on the immune cells.
The IS cells, as they are formed and mature, learn how to recognise the MHC proteins present in our own cells.
Self and non-self
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8. T B The white blood cells PHAGOCYTES LYMPHOCYTES Monocytes Macrophages
Dendritic cells (DC) T B Th Ts Tc
EOSINOPHILS (antiparasites)
BASOPHILS (inflammation and allergies)
MAST CELLS (release of histamine in tissues)
NK (destroy infected cells and tumor cells)
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10. How does the immune system work?
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11. How does the immune system work?
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12. THE INNATE RESPONSE
INVOLVES Physical and chemical barriers; phagocytes and plasma proteins (interferon, activation proteins, clotting factors and complement proteins)
PREVENTS infection and the invasion of pathogens to the circulatory system
PRODUCED following skin damage; viral, bacterial or extracellular parasite infection
TYPE OF RESPONSE: fast; recognises generalised ancestral antigens; local and short-lived.
What happens?
Increase in temperature (e.g. fever)
Inflammation and histamine release
Phagocytosis and antigen presentation
Clotting (if capillaries were injured)
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13. THE ADAPTATIVE RESPONSE
INVOLVES antigen presenting cells, B & T lymphocytes, antibodies, interleukines and memory cells
FIGHTS AND DESTROYS pathogens present in blood.
PRODUCED following systemic viral or bacterial infections or intracellular parasites.
TYPE OF RESPONSE: slow, recognises specific and new antigens, acquired, general and long-lived.
What happens?
Recognition of foreign antigens
B cell activation and production of antibodies
T cell activation and antigen clearance
Production of memory cells
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14. What are white blood cells for?
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15. Phagocytosis and antigen presentation
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16. Antigen Presenting Cells (APCs)
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17. B LYMPHOCYTES
B lymphocytes form and mature in the bone marrow; later they migrate and reside in the lymphatic nodes and spleen
Once activated, they undergo clonal expansion and turn to plasma cells and memory cells
Activated B cells produce and secrete specific proteins called ANTIBODIES
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19. Antibodies
They are proteins produced by the plasma cells (activated B lymphocytes) in response to a specific antigen.
Antibodies neutralise antigens through several diverse mechanisms.
There are 5 different classes of antibodies.
Each antibody has 2 heavy chains and 2 light chains, with variable and constant regions.
The variable region recognises the antigen.
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20. What do the antibodies do?
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21. Antibodies in pharmacology and medicine
In 1974 Milstein describes a technique to produce monoclonal antibodies, i.e. those that derive from a pure cell line, highly specific. This achievement earned him
the Nobel prize in 1984.
These mAb are currently used for:
Clinical diagnosis:
Pregnancy test
HIV, hepatitis and rotavirus test
Drugs, hormones and cancer detection
Molecular and biochemical studies:
to study tumor cells
In cellular adhesion studies
To study intra/extracelullar signals
To make vaccines
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22. T LYMPHOCYTES
T cells are made in the bone marrow and mature in the thymus gland and spleen.
T cells recognise antigens present in the B cells and the APCs.
T cells release activation signals
T cells regulate the other IS cells activity and destroy infected cells.
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23. HUMORAL AND CELLULAR IMMUNITY
Humoral response: involves antibodies
Cellular: involves T lymphocytes and NK cells
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24. Difference between humoral & cellular response
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25. Interaction between B and T lymphocytes
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27. Active and passive immunity
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28. Primary and secondary response
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29. Vaccines
Activate the immune system and stimulate the production of memory cells.
They have a long term effect.
A boost dose is needed every ten years.
Made of inactivated pathogens, modified pathogens, fragmented pathogens, or only the antigens capable of the immune response to that pathogen.
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30. Modelising the immune system
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