1. The Immune System
“The security force”

2. Crash course overview- Immunity

3. Organization of the Immune System
Non-Specific
Provides same general defense against anything not self
Present from birth
Specific Immunity
Recognizes specific threats and mounts targeted attacks
Creates a long term memory

4. Non-Specific Immunity
Species Resistance
A biological basis - keeps humans from getting sick from plant or other animal diseases.

5. Non-Specific Immunity
First Line of Defense
Mechanical and Chemical Barriers
The skin is often called the first line of defense.
Mucus, sebum and enzymes will catch or destroy pathogens

6. Non-Specific Immunity
Second Line of Defense
The Inflammatory Response
Tissue damage causes the release of chemotactic factors such as histamines, kinins and prostaglandins that attract WBCs.
This response causes redness, swelling and pain because of increased blood flow.

7. The
Inflammatory
Response

8. Non-Specific Immunity
Phagocytosis
Phagocytes are WBCs that ingest non-self substances.
Neutrophils are the most common phagocytes.
Monocytes (macrophages) are giant phagocytes.
Phagocytes accumulate as pus at site of infection.

9. Macrophages have different names based on where they are found.
Phagocytosis
Macrophages have different names based on where they are found.

10. Non-Specific Immunity
Natural Killer (NK) Cells
They ingest tumor cells and cells infected by viruses.
They do not need to be activated by a specific antigen.

11. Non-Specific Immunity
Interferon
Cells infected by viruses release the protein interferon.
Interferon prevents viruses from multiplying in cells and is used in treating cancers.

12. Non-Specific Immunity
Complement
20 inactive enzymes are activated in a series to cause the lysis of a foreign cell.

13. Specific Immunity Third Line of defense
Two types of WBCs that arise from hematopoitic stem cells are involved in specific immunity
B lymphocytes and
T lymphocytes

14. actions are referred to as antibody-mediated immunity
Specific Immunity
B Cells
Create antibodies
antibodies bind to and clog up cells and viruses leaving them for phagocytes to attack
actions are referred to as antibody-mediated immunity

15. Actions are considered cell-mediated immunity
Specific Immunity
T cells
Mature in the thymus
Attack cells directly
Actions are considered cell-mediated immunity

16. Lymphocyte Circulation
Most B and T cells are found in the thymus, spleen, lymph nodes, and bone marrow.
Lymphocytes leave tissue through lymphatic vessels and are eventually returned to the blood via the right and thoracic lymphatic ducts

17. Specific Immunity
Antigens are markers on the outside of foreign cells that induce an immune response with their epitope markers.
Antibodies are plasma proteins called immunoglobulins that have two small regions called combining sites.
Epitopes of anitgens fit into specific antibody combining sites to form an antibody-antigen complex

18. Crash course – humoral response

19. Antibody-mediated Immunity
Stem Cells
Shortly before and after birth develop into
Inactive B cells
They migrate to spleen, liver and lymph nodes. Binding of antigen to antibody changes them into
Active B cells
Divide rapidly forming clones
Plasma cells
Memory Cells
Stored in lymph nodes
Secrete into blood
Antibodies
YYYYYYY

20. Antibodies Immunoglobulins are Y-shaped proteins They have two heavy
and two light
polypeptide chains
Variable regions at the end of each arm allow for specific antigen binding.
Chains are bound together by disulfide bonds
Each has two complement binding site

21. Antibody Functions
By binding chemical toxins they can convert them to harmless substances
They can cause agglutination of antigens on the surface of microorganisms making it easier for phagocytic cells to digest them
Binding to antigens can cause a change in antibody structure exposing the complement binding site initiating complement enzyme reactions which destroy the cell
Complement binding site

22. Antibody Functions

23. Complement Action

24. Classes of Antibodies (Immunoglobins)
Immunoglobulins M, G, A, E and D
IgG- most abundant, produced by secondary immune response, confers passive immunity to infants from mother
IgM- produced after initial contact with antigen in primary response
IgA- found in mucus, saliva and tears.
IgE- associated with allergies, can be harmful
IgD- present in small amounts, exact function unknown.

25. Classes of Antibodies (Immunoglobins)

26. Cell-Mediated Immunity
T cells mature in thymus into thymocytes
Contain antigen binding sites on their surface
Once activated they become either cytotoxic (killer T cells), helper T cells, suppressor T cells or T memory cells
Sensitized T cells release chemotatic factors that attract macrophages to the site of infection
Helper T cells help with B cell secrete antibodies
Suppressor T cells help turn off B cells

27. Cell-mediated Immunity
Stem Cells
Shortly before and after birth develop into
T cells
They migrate to thymus, spleen, liver and lymph nodes. Binding of antigen to antibody changes them into
Sensitized T cells
Cytotoxic T cells
Suppressor T cells
Helper T cells
Memory T cells
Seek out cells with specific antigens and destroy them, release chemotatic factors increasing phagocytosis
Prevent B cells from converting into plasma cells
Help B cells convert to plasma cells to create more antibodies
Antibody producing cells

29. Immunization

30. Passive and Active Immunity
Natural Immunity
Exposure to agent is not deliberate
Passive Immunity
Fetus receives protection through placenta
Infant receives protection from breast milk
Injection of antibodies that were created by another individual’s immune system
Artificial Immunity
Exposure to agent is deliberate
Active Immunity
Child develops measles and has protection from further infections
Injection of agent such as a vaccine

31. Disorders of the Immune System
Allergies
Autoimmune Disease
Acquired Immunodeficiency Syndrome

32. Allergies Hypersensitivity to usually harmless substances
Allergens are substances that cause allergic responses
IgE plays main role in allergic response
Usual symptoms, are runny nose, conjunctivitis, hives
Anaphylactic shock can result in severe responses and can lead to death if untreated
Antihistamines normally relieve symptoms but adrenaline may be needed in severe cases

33. Autoimmune Disorders
Inappropriate or excessive response to self-antigens.
3 out of 4 cases affect women
IgG antibodies are made against self DNA
Examples
Systemic Lupus
Multiple sclerosis
Diabetes mellitus
Grave’s disease
Myasthenia gravis
Treatment usually focuses on relieving symptoms

34. Acquired Immune Deficiency Syndrome
Caused by the HIV virus, a retrovirus
Virus attacks T lymphocytes and immune system is destroyed
Persons are susceptible to unusual forms of cancers and infections that can lead to death
A “cocktail” of antiviral are currently used to keep the infection from developing into AIDS