IMMUNITY

1. IMMUNITY Dr. L. Rueda CUHS

2. I. The lymph is a circulatory system with many functions A. Lymph vessels surround blood vessels1. One cell thick2. Fluid is similar to blood, but compatible with fat solubles3. Has no ‘pump’ ( no heart), operates by muscle contractions and gravity * Edema ( tissue swelling) of bedridden patients is apt to be due to this system not working correctly4. Backflow is prevented by valves

3. B. Operation1. Lymph vessels are net like (more permeable than blood vessels). 2.Collect excess fluid from tissues and dump into heart3. Fluid is recycled through circulatory system

4. C. Functions1. Pick up fluid and waste2. Nodes of the lymph produce antibodies ( lymphocytes ) necessary to fight infection. These circle through lymph and blood * During infection, lymph nodes swell as WBC fight it

5. II. Immunity: reaction of the body to foreign agents (microbes, parasites, chemicals, cancer). Takes four forms: A.Natural : immunity that the body makes on its own, innate B. Acquired: immunity after exposure to an antigen, or, vaccine C. Nonspecific: does not target specific organisms D. Specific: antibody, or protein, response to specific targets

6. II. Nonspecific immunity A. Physiological barriers: skin and mucous membranes act as barrier1. Skin has pH of 3 to 5, impermeable to bacteria and virus *Oil and sweat give lowered pH2. Mucous, saliva, tears can wash away bacteria * Contain lysozyme3. Nostrils filter pollen4. Stomach acid kills bacteria

7. B. Phagocytic immune cells target microbes, dead cells1. Phagocytes are cells that eat other cells or invading objects2. Neutrophils (70% WBC) move like amoeba, surround and kill bacteria, Then they themselves die.3. Monocytes (5%WBC) become macrophages, large amoeboidsTheir enzymes and reactive oxygen break down bacteria, dead neutrophils, dead RBC’s4. Eosinophils: (2%WBC) attack parasitic worms

8. C. Molecules in the blood, proteins, do not ‘kill’ invaders, but limit their reproduction1. Interferons are proteins made by virus infected cells. They *Are a form of ‘self-vaccination’. They migrate to adjacent cells and cause them to have an immune response. *Attack viruses, and are nonspecific. Have a short termeffect *We are mass producing them (DNA tech) as cold vaccines

9. D. Certain cells produce chemicals called cytokinens, which breakdown microbes. Similar to interferons

10. E. The inflammatory response to cuts is nonspecific1. Open wounds harbor bacteria. To kill bacteria, they need WBC’s2. To get WBC’s, we need extra blood flow so...3. Basophils in the blood release histamine causing vasodilation4. Dilated capillaries are leakier 5. Redness is due to increased capillary blood flow

11. 6. Swelling is due to increased permeability of blood vesselsallowing WBC’s to migrate into the tissues *Neutrophils come first, they die *Macrophages come an finish the job, and digest the waste * Clotting proteins seal off the area

12. III. Specific immunity: antibodies/proteins produced by B and T cells. A. Terminology1. Immune response; a recognition system which distinguishes between self and nonself2. Antigen-foreign substance3. Antibody- a specific defense protein which helps to control antigens from damaging the body

13. 4. Immunity- protection afforded to a body by previous exposure to an antigen5. Active immunity- with encounter to an actual virus or bacteria body is producing antibody6. Passive immunity- temporary acquired antibodies passed on to organism ( vaccine)

14. B. Antigens are generally foreign particles invading the system1. Antigens each have a specific conformation2. This shape is recognized by the antibody/protein 3. Are large proteins or polysaccharides, contain an active site known as an epitope.4. Two types of immunity cells are made in the bone marrow * B cells-secrete antibodies , extracellular * T cells- function within cell

15. C. Humoral Immunity: the body fluids contain B cells which make antibodies. Found in blood and lymph1. Fights toxins, bacteria, viruses2. B cells form in the bone marrow and mature at the lymph nodes.3. Become activated in presence of antigen * Form effector cells-->plasma cells--> secrete antibodies

16. 4. Antibodies are specialized proteins: immunoglobulins (Ig) * Are Y shaped. The Constant, or ‘C’ area is the stem * The Branched ‘V’ top is variable * Act by binding to antigen and either changing its shape or Causing it to agglutinate (clump-blood cells)

17. C. Humoral Immunity: the body fluids contain B cells which make antibodies. Found in blood and lymph1. Fights toxins, bacteria, viruses2. B cells form in the thymus, but mature in the bone3. Become activated in presence of antigen * Form effector cells-->plasma cells--> secrete antibodies

18. 4. Antibodies are specialized proteins: immunoglobulins (Ig) • * Are Y shaped. The Constant, or ‘C’ area is the stem • * The Branched ‘V’ top is variable • * Act by binding to antigen and either changing its shape or • Causing it to agglutinate (clump-blood cells)

19. 5. Occurs mainly in lymph nodes • 6. Targets extracellular invaders, ie those circulating in the blood stream, tissues, spleen, and lymph . Causes invaders to: • * Be neutralized- surround it so that phagocytes can then eat it • * Agglutinate- bind together many antigens so that phagocytes can eat • * Precipitate:similar to agglutination

20. C. Cell mediated immunity: intracellular phagocytosis, by T cells • 1. Once pathogens invade the body’s cells, pass cell membranes, they are harder to target • *Recognize this type of invader through the MHC (major histocompatability complex, a group of proteins unique to each human, to each cell) • * T cells recognize the normal MHC composition of cell membranes. Red flag when a ‘foreign’ component shows up

21. 2. T and B cells start out in the bone marrow. T cells must travel through the thymus to mature • 2. T cells have three forms • * Cytotoxic T’s : kill invaders expressing foreign antigens • produce chemical toxin- perforin. Attack cancer and viruses • *Helper T cells: produce cytokines, chemicals which bind to membranes of foreign substances, alter its composition, digest it • * Suppressor T cells- inhibit the activity of other t-cells • these are necessary for feedback inhibition

22. D. Autoimmunity: We must be able to recognize ALL the chemicals, enzymes and proteins in our own bodies. MHC does this • 1. Major histocompatability complex: 40 enzymes/proteins that recognize organs/tissues. Only alike in identical twins • 2. Cyclosporin: suppresses this response, but allows some humoral immunity. This facilitates organ transplants

23. IV. Immune response is a two stage process: • A. Primary response: first contact either with the disease, or vaccine • 1. Vaccines can be dead or heat weakened cells, or inactive bacterial toxins • 2. The lymphocytes create ‘clone cells’ which begin to produce the antibody, or T cell product. • 3. Takes 5-10 days for maximum production (Rh factor- 2 months) • B. Secondary immune response. The next encounter is swift. Can be several minutes to 5 days to fight invader • 1. Each response will be stronger • 2. An allergic reaction can occur id body ‘over-reacts’

24. V. Immune system diseases • A. Autoimmune diseases: flaws in MHC, lupus (skin and internal organs get scarring), rheumatoid arthritis, insulin dependent diabetes( self attacks pancreas destroys cells). Graves (thyroid) • 1. Lupus; body directs WBC towards own tissues. Causes inflammation and injury • * Attacks: skin, kidneys, muscles, lungs, heart, blood • *Attacks women 8-10 times more then men • *Disease cycles, and varies in devastation • * Fever, rash, weight loss are initial symptoms • *advanced lupus- causes skin pulling, tight, lesions, destroys organs with scarring

25. B. Allergy: an oversensitive immune system reacts to an otherwise harmless substance (called allergens). • 1. Specific antibody (E or IgE) made. • 2. This antibody causes excess histamine to be released

26. C. Anaphylactic shock: acute allergic response. • 1.Histamine production is excessive. • 2. Blood vessels dilate so rapidly that blood pressure drops. • 3. Can be fatal in 3-5 minutes. Three main causes: peanuts, shellfish, bee stings.

27. D. Immunodeficiency: general inability to fight invaders • 1. SDID: rare genetic disorder, ‘bubble’ kids, live in space suits • are know treating with bone marrow transplants (immune system cells are made in the marrow) • 2. Lymph cancer- immune cells reproduce uncontrollably • Leukemia, and Hodgkin’s disease • 3. HIV - AIDS- reduced Th cell count, suppresses both H and T cells • *Don’t die of AID’s , but of a 20 infection • *HIV is provirus, attaches to CDH receptor complex to enter cell • * USA: drugs/homosex. Africa: heterosex/ nursing/hygiene

28. VI. Immune response depends on age, health, particular antigen • A. Age- immunity is enhanced by aging, to a point • 1. Develop more b cell responses • 2. Babies get through mother’s early milk ( colostrum), one of main benefits of nursing. • * Babies treat foods as antigens . Must allow immune system to develop before food is given • * When first given food, introduce one food every two weeks, allowing body to adjust • B. Heredity-genes determine your ‘self’ markers

29. VII. Current treatments are in the infancy stages • A. Recombinant DNA technology- developing appropriate antibodies • 1. Being used for rheumatoid arthritis • B. Organ transplant- necessary for other reasons, but susceptible to rejection as the MHC is different in every person, even twins • 1. Treat with drugs • 2. Using DNA technology to infuse ‘self’ into donated tissue • C. Vaccines for retroviruses (AIDS) and certain cancers • D. Treatment with a man made ‘t-cell’ chemical- interleukin-2 • E. Cloned B cells (man made antibodies- monoclonal antibodies)