1. Chapter 24
The Immune System

2. Pathogenicity of microbes
Pathogens are microbes that can cause disease.
Toxins are small organic molecules or pieces of protein or bacterial cell wall that are released when bacteria die.

3. How do pathogens get in? Adhesion Factors
Adhesion factors allow a pathogen to bind to certain cells.
Viruses have spikes that bind to host cell surfaces.
Invasive mechanisms determine the extent of a disease in the body.
Localized vs. Systemic.

4. Epidemiology
The study of the factors that influence transmission of diseases in human populations.
Infectious diseases; illnesses caused by pathogens, or their products.
Highly transmissible pathogens (virus, bacterial) are contagious.

5. Transmission of Diseases

6. Viral Diseases
Influenza (the flu)- fever, chills, vomiting, cold symptoms.
Influenza or "flu" is an infection of the respiratory tract that can affect millions of people every year. It is highly contagious

7. Body Defenses: Overview
Physical barriers: skin & epithelial linings & cilia
Immune defenses – internal
Innate, non-specific, immediate response (min/hrs)
Acquired – attack a specific pathogen (antigen)

8. Lymphatic System: Overview of Immune Defense Organs & Cells
Figure 24-2 ab: Anatomy of the immune system

9. The Composition of Whole Blood (4-6L in an adult)
The percentage ranges for white blood cells indicate the normal variation seen in a count of 100 white blood cells in a healthy individual.

10. White Blood Cells (leukocytes) (0.1% of formed elements)
Defend the body against pathogens
Two classes
Granular leukocytes
Neutrophils (polymorphonuclear leukocytes)
Eosinophils
Basophils
Agranular leukocytes
Monocytes
Lymphocytes

11. Neutrophils Neutrophils Acute inflammation Highly mobile phagocytes
Containing bacteria-killing enzymes
Multi-lobular nucleus

12. More Granular Leukocytes (granulocytes)
Eosinophils (acidophils)
Stain with an acidic red eosin stain
Attracted to foreign compounds reacted with antibodies
They kill pathogens by releasing substances that kill them.
2-lobed nucleus

13. Basophils
Stain with a deep purple or blue basic dye
Migrate to damaged tissue and release their granules
Release histamines.
Inflammatory response; increase capillary permeability.

14. Agranular Leukocytes (agranulocytes)
Monocytes
Migrate into peripheral tissues
Are precursors to macrophages.
Highly mobile phagocytic cells
Oval, kidney-bean shaped nucleus

15. Agranular Leukocytes (agranulocytes)
Lymphocytes (specific immunity)
Primary cell of the lymphatic system
T-cells attack foreign cells directly
B-cells produce antibodies that bind foreign particles
NK cells; immunological surveyors. Always remain in circulation. They don’t take up residence in tissues.
Large round, purple staining nucleus.

16. The immune response. Two types
INNATE IMMUNITY: NON-SPECIFIC
ACQUIRED IMMUNITY: SPECIFIC

17. Innate Immunity: Phagocytosis & Inflammation
Phagocytosis: Just eat it.
THE PHAGOCYTES
macrophages, neutrophils, NK cells
Engulf and digest recognized "foreign" cells – molecules

18. Our immune system tags the foreign particles
Opsonins- are the tagging proteins that make unrecognizable particles into “food” for phagocytes.

19. Innate Immunity: Phagocytosis & Inflammation
Figure 24-6: Phagocytosis

20. Inflammatory Response: hallmark fo the innate immune pathway
1. acute phase
attract immune cells to the infection site; neutrophils
basophils to produce histamine to flush out the area;edema swollen redness.
2. produce a physical barrier to retard spread of infection.
3. promote tissue repair post-infection; not an immune function.
Histamines: from mast cells  swelling, edema, b. v . dilation
Interleukins:
Secreted by macrophages
Stimulate liver production of acute phase proteins (opsonins)
Alter the blood endothelium to ease the passage of WBCs.
Bradykinin: stimulates pain & swelling to draw attention to the wound
Membrane attack complex proteins (25 complement proteins). . .

22. Inflammatory Response: Cytokines Signal Initiation
Figure 24-8: Membrane attack complex

23. Some complement proteins are “warning proteins”
Interferon is one such warning protein. Virus-infected cells produce this protein which in turn binds to receptors of noninfected cells causing them to prepare for possible attack.
interferon
Virus infected cell
Watch
Out
guys

24. Acquired Immunity: Lymphocytes B cell and T cells
lymphopoiesis

25. Lymphocytes Cytotoxic T cells
Attack foreign cells or bodies infected with viruses
Cell-mediated immunity
Regulatory T cells
Helper or suppressor T cells
Regulate and coordinate immune response
Memory T cells
Remain “on reserve”

28. Lymphocytes B cells Plasma cells produce antibodies
Antibody-mediated immunity
B cells
Plasma cells produce antibodies
React to specific antigens
Immunoglobins
Antibody mediated immunity
Memory B cells

30. Acquired Immunity: Antigen-Specific Responses
Figure 24-13: Functions of antibodies

31. T Lymphocytes: One more detail. . .
Major histocompatability complex (MHC)
These incorporate antigen gragments and present them to the T cells; they come in two flavors:
MHC class I
MHC class II

32. Non-self proteins HLA antigens (MHC proteins) Self-proteins. Antigen
Being
Presented
To the
T-cell.
HLA antigens
(MHC proteins)
Self-proteins.

33. T Lymphocytes: Cell Mediated Immunity
Figure 24-16: T lymphocytes and NK cells

34. Blood Types: Like Antibodies & antigens will agglutinate
Antigens on RBCs (A, B, AB or none = O)
Antibodies in plasma (anti A, anti B, anti AB)
Rh antigens & antibodies

35. Blood typing depends on RBC antigens
Presence or absence of specific surface antigens on RBC cell membranes. An antigen is a genetically determined glycoprotein. There are 3 antigens we type for:
A, B, and D (Rh)
Antibodies attack “foreign” surface antigens. YOUR antibodies NEVER attack your antigens.

36. Blood Type A person with: Type A blood
Surface antigen A, anti-B antibodies
Type B blood
Surface antigen B, anti-A antibodies
Type AB blood
Surface antigens A and B, no A or B antibodies
Type O blood
No surface antigens, both anti-A, anti-B antibodies
Rh positive has the Rh surface antigens and no Rh antibodies

37. Figure Blood Typing
The blood type depends on the presence of agglutinogens on RBC surfaces.

38. Blood Typing

39. INDUCED IMMUNITY

40. INDUCED IMMUNITY
ACTIVE IMMUNITY- inject a bit of the antigen (vaccine) and let the body’s immune system make antibodies against it.
IMMUNIZATION

41. “BOOSTER”

42. Active Immunity.
Dependent upon the presence of memory B and T cells capable of responding to lower antigen doses.