1. Chapter 43: The Immune System
Disease
A departure from health
Types:
Deficiency diseases
Genetic diseases
Communicable diseases
Contagious disease
Infectious disease
Host provides metabolic needs of pathogen or parasite

2. Infectious disease Transmission Types Contact Droplet infection Vector
Common vehicle transmission
Types
Sporadic disease
Endemic disease
Epidemic disease
Pandemic disease

3. Adaptations of pathogen to resist host defense
Cell wall
Contain proteins to resist host &/or antibiotics
Sticky capsule
Counters phagocytosis; increases virulence of pathogen
Production of enzymes or metabolic toxins
Manipulates host cell’s metabolic structure
viruses

4. Adaptations of the Human Body
1st line of defense
Physical shield
Skin, mucus, ciliated cells, tears, urine flow, coughing, sneezing, ear wax
Chemical shield
Stomach acids kill bateria
Enzymes (lysozyme) in tears etc.
Skin acids
2nd line: inflammatory response
Increased blood flow
Promotes healing
Swelling insulates tissues

7. Macrophages, neutrophils, Eosinophils, & Dendritic cells
Phagocytic activity to engulf pathogen
Macrophages:
Develop from monocytes
Migrate through the body or reside permanently in some organs (i.e. spleen)
Neutrophils:
Enter infected tissue to engulf microbes
Self destruct
Eosinophils:
Position against multi-cellular parasite & release enzymes to destroy
Dendritic cells:
Can act like macrophages but are usually involved in acquired immunity

8. Injured, circulating basophils release histamines & prostaglandins
Promotes vasodilation
Capillaries become “leaky”
Attracts phagocytic cells
Neutrophil engulfs bacteria macrophage engulfs neutrophil
Infected cells release interferon
Stimulate adjacent cells to produce proteins that prevent viral replication
Activates phagocytes

10. 3rd line: Immune response
Production of Lymphocytes
Circulate in blood & lymph
Concentrated in spleen, lymph nodes, & lymphoid tissue
Each lymphocyte is specific to a particular foreign antigen
Originate in stem cells of bone marrow
Types:
B cells
Mature in bone marrow
T cells
Mature in thymus gland
Maturing B cells & T cells tested for self-reactivity & destroyed if self reactive

12. Production of specific antibodies by lymphocytes
Antitoxins
Neutralize bacterial toxins
Agglutinins
Clumping of bacteria
Opsonins
Stimulate phagocytosis of clumped bacteria
Lysins
Dissolve cell walls of bacteria
Precipitins
Coagulation chemicals of bacteria

13. Immunoglobins (antibodies)
Specific antigen binding immunoglobulins
Generated by B cells
Types
IgM
First antibodies to arrive at infection site
IgC
Most abundant antibodies in blood & lymph
IgA
Antibodies found in body secretions (saliva, sweat)
IgE
Trigger release of histamines & other chemicals by mast cells & basophils to cause allergic reactions
IgD
On naïve B cells (not yet exposed to foreign antigen)
Receives antigen that leads to clonal selection

16. Self/non-self
Immune system must be able to distinguish foreign from non-foreign proteins
Major histocompatability complex (MHC)
Group of glycoproteins embedded in cell membrane
Two major classes of MHC
Class I MHC
Bind to cytotoxic T cells
Class II MHC
Known as antigen presenting cells
Bind to specialized cells (macrophages, B cells) & activate T cells

18. Action of lymphocytes Humoral Response B cells Helper T cells
Enter blood & produce specific antibodies to counter specific antigens
Antigen-antibody complexes are formed
Helper T cells
Secrete interleukins
Stimulate clonin of B cells to memory cells
B cells into memory cells (M cells)
Long lived cells
Recognize specific antigen
Basis of active immunity
Plasma cells (P cells)
Short lived cells
Produce additional antibodies with initial exposure to antigen
Antibodies draw phagocytic cells in to destroy

23. Cell mediated response
Cytotoxic T cells
Stored in thymus gland prior to moving into blood
Activated when CD8 receptors recognize antigen on Class I MHC; helper T cell releases cytokines to promote activation
Do not produce antibodies
Attack & kill antigen-bearing cells
Secrete proteins that destroy infected cells
Stimulate the production of B cells
Dispose of infected cells
Suppress B cell reproduction when infection has been suppressed
Secrete interferon which defends healthy cells from virus

26. Primary vs. Secondary immune response
Primary immune response
First exposure or vaccination to antigen
Results in formation a specific antibody to inactivate an antigen
Requires time to occur
Secondary immune response
Rapid reproduction of specific antibodies to inactivate & destroy antigen (immediate)

27. Types of Defense Innate immunity Acquired immunity/adaptive immunity
Present at birth without any exposure
Non-specific
Acquired immunity/adaptive immunity
Develops after exposure
Highly specific
Recognition by lymphocytes

28. Types of immunity Natural immunity Active immunity
Inherited immunity (parent to child)
Active immunity
Long term immunity due to
Exposure (i.e. chicken pox, mumps, measles)
Vaccination
Intentional exposure to weakened/dead pathogen or pathogenic toxin
Immunization
Polio...

29. Passive immunity Borrowed or temporary immunity through
Injection of antibodies
Blood serum or gamma globulin injections
Immediate immunity
Short term immunity
Memory cells are not produced

30. Blood Groups effect on transfusions & transplants
Antibodies present against non-self blood types without exposure
result of reaction to bacterial antigens
MHC molecules stimulate immune response leading to tissue rejection
each person has a unique polymorphic combination of MHC molecules

31. Exaggerated, self-directed or diminished immune response & disease
Allergies
Hypersensitive response to antigens on allergens
Often involve IgE antibodies
Attach to mast cells to induce histamine release
Anaphylactic shock
Whole body, life threatening allergic reaction
Autoimmune disease
Body generates antibodies against self
Ex. Lupus, rheumatoid arthritis, multiple sclerosis, diabetes mellitus

33. Immunodeficiency diseases
Inborn or primary
Caused by genetic or developmental defect
Defect in production of immune cells or specific proteins
Acquired or secondary
Develops later in life
Caused by exposure to agents or disease
Ex. Hodgkin's, AIDS