1. Chapter 24- The Immune System
Active immunity
Allergen
Allergies
Anaphylactic shock
Antibody
Antigen
Antigen receptors
Antigen-binding site
Antigenic determinants
Antigen-presenting cells
Antihistamine
Autoimmune diseases
B cells
Cell-mediated immunity
Clonal selection
Complement proteins
Cytotoxic T cells
Helper T cells
Histamine
Humoral immunity
Immune system
Immunity
Immunodeficiency diseases
Inflammatory response
Interferons
Lymph
Lymphatic system
Lymphocytes
Macrophages
Major histocompatibility complex
Mast cells
Memory cells
Monoclonal antibodies
Monocytes
Natural killer cells
Neutrophils
Nonself molecules
Passive immunity
Perforin
Plasma cells
Primary immune response
Secondary immune response
Self protein
T cells
Vaccination
Vaccine

2. Immune system
Protects the body by recognizing and attacking specific kinds of pathogens and cancer cells
There are both nonspecific and specific responses against infection

3. 1st line of defense is nonspecific
Nonspecific = (can’t distinguish a certain pathogen)
Intact skin- barrier that pathogens can’t penetrate
Acids secreted by glands in skin- inhibit microbe growth
Sweat, saliva, tears- contain lysozyme- an enzyme that attacks bacterial cell walls
Digestive and respiratory systems- guarded by mucous membranes (b/c they are exposed to env)
Stomach acid- kills bacteria
Hair in nostrils- filters air
Mucous in respiratory system traps particles and cilia sweep them out

4. Nonspecific defense cells
Neutrophils, monocytes and macrophages- engulf bact and viruses
Natural killer cells- attack cancer cells and infected body cells (especially those that harbor viruses)

5. Proteins also attack microbes or impede reproduction
Interferons- proteins that are produced by cells that are infected by a virus to help other cells resist virus
Nonspecific, short term, can be used to treat certain cancers
Complement proteins- circulate in plasma, activated by immune system or microbes, stick to surfaces for macrophages to notice, cut holes in cells, amplify nonspecific responses

6. Inflammatory response

7. Inflammatory response
Major component of nonspecific defense
red, swollen, warm “inflamed” –due to increase in blood flow, fluid and cells
Damaged skin releases chem signal (histamine)
It induces blood vessels to dilate and become leaky
Blood flow to area increase, plasma moves to interstitial fluid
Other chem’s attract phagocytes
Results: disinfect area, engulf bacteria
Clotting proteins- seal off infected region
Response can be local or systemic (WBC’s increase, fever, high fever, low BP-septic shock)

8. The Lymphatic System
Returns tissue fluid to circ system and fight infection
Consists of: vessels, lymph nodes, tonsils, adenoids, appendix, spleen, bone marrow, thymus
Involved in: nonspecific and specific resistance to infection
System is where fluid that has left circ system returns to, happens by diffusion
Infection fighting occurs in lymph nodes and other vessels which are packed with WBC’s
Sometimes they become swollen when fighting infection

9. The Lymphatic System

10. Specific Immunity Immunity- resistance to specific invaders
Active- when antigens enter body (getting sick/a shot)
Passive- antibodies are passed (fetus from placenta, sometimes when travelling to other countries)
Antigen- “antibody generating”- elicits immune response
Molecules on surfaces of cells
Antibody- protein in blood plasma that attaches to particular antigen and help counter its effect
*****has a good memory*****

11. Lymphocytes White blood cells Originate in bone marrow
Spend most of their time in tissues and organs of lymphatic system
Produce specific immune responses
Response to antigens in 2 ways:

12. Lymphocytes Mature in thymus =T cells Mature in bone marrow= B cells
Cell-mediated immunity
Attacks infected body cells
Promotes phagocytosis and stimulates B cells (so T cells are involved in both)
Can be transferred passively (injecting T cells)
Mature in bone marrow= B cells
Humoral immunity
Secretes antibodies
Can be transferred passively (injecting antibodies)
Antigen receptors- molecules on cells surface, bind to antigen
100mil to 100bil different kinds of B and T cells!

13. Lymphocytes

14. Antigens Most are proteins or polysaccharides
Antigenic determinants- region that antibody recognizes
Site on antibody (antigen-binding site)- recognizes determinant
*complementary shape

15. Antigens
Activate lymphocytes to multiply that are specific to the antigen- clonal selection
Effector cells produced secrete antibodies
This happens with B cells and T cells

16. Primary Immune Response
1st time lymphocytes are exposed to antigen and clonal selection happens
Takes a few days before lymphocytes are activated

17. Secondary Immune Response
After 2nd exposure to same antigen
Produces very high antibody levels, lasts longer
Each antigen exposure triggers clonal selection
Cells of the clone include:
Memory cells- last for decades, remain in lymph nodes, when activated-trigger secondary response, multiply quickly
Effector cells- produce antibodies

18. Humoral vs. Cell-mediated Immunity

19. Humoral Immunity In body fluids
Effector cells produced during clonal selection are called plasma cells
Plasma cells then secrete antibodies

20. Antibodies 2 heavy chains and 2 light chains bonded together
2 functions: recognize and bind to antigen & neutralize the antigen
Structure allows function
Antigen-binding sites in V region
Mark antigens for elimination
Binding creates antigen-antibody complex

21. Methods for antigen inactivation:
Neutralization- antibodies block antigens from binding with cells, phagocytes engulf complex
Agglutination- “clumping” – clumps invaders together making it easier for phagocytes to capture
Precipitation- link antigen molecules together and they precipitate out of solution as solids, easily engulfed
Activation of complement proteins by antigen-antibody complex- proteins open holes in plasma membrane, cell lyses

23. Monoclonal antibodies
Antibody secreted by a clone of cells that’s specific for an antigen
Ex: pregnancy test- binds to hormones, STD test-binds to bacteria

24. Cell-mediated Immunity
T cells respond to antigens on body’s own cells
Cytotoxic T cells- attack infected body cells
Helper T cells- help activate cytotoxic T’s and macrophages, and stimulate B’s to produce antibodies
Antigen-presenting cells (APC’s) – present antigens to helper T’s- triggering pathway to activate helper T’s

25. When a T cell is activated:
Grow and divide, producing more helper T and memory T cells
Stimulate cytotoxic T’s
Bind to infected cells and form holes in membrane
Activate B cells
Cytotoxic T cells also can recognize changes in membranes of cancerous cells and destroy them

26. Immune system depends on our molecular fingerprint
Recognizes “self” and “non-self”
What if that doesn’t work?

27. Immune System Disorders
Autoimmune disease- immune system attacks body’s own cells
MS, lupus, insulin-dependent diabetes

28. Immune System Disorders
Immunodeficiency disease- when a component of the system is lacking
Can be caused by physical and emotional stressors
AIDS, SCID, Hodgkins disease
HIV virus destroys helper T cells
Allergies- overreaction of the immune system
Antigens that cause allergies are called allergens