1. Immunology

2. Immunity – First Line of Defense (Keeping pathogens from getting in)
Skin and mucous membranes
Epithelium traps pathogen – swallow or expel them from the body
Secrete oil and sweat – kills pathogens with a pH of 3-5
Lysozyme is produced by eyes and upper respiratory tract – digests cell walls so kills bacteria

3. Immunity – Internal White Blood Cells/Proteins
Non-Specific
Cells (develop in bone marrow)
Neutrophils
Eosinophils
Basophils
Moncytes
Natural Killer Cells
Proteins
Specific
B-cells
originate from bone marrow
Make anti-bodies – destroy soluble pathogens
T-cells
Originate in bone marrow and then go to thymus
T-killer – kill tumor cells and infected cells
T-helper – activate T and B cells

4. Non-Specific Immunity
Quick, short-lived, activated specific immunity
Activated by damaged cells releasing chemical attractants or break in skin
Limits the spread of pathogens

5. Non-Specific Immune Cells
Neutrophils ( 60-70% of WBC’s) First responders
Enter tissue, phagocytize invaders, die in the process
Monocytes ( 5% of WBC’s)
Enter tissue, become macrophages (lg. phagocytes), kills cells by NO, reactive oxygen, and digestive enyzmes in their lysosomes
Releases cytokines to attract other immune cells
Later act as APC’s (antigen presenting cells) to specific immune cells

6. Non-Specific Cells continued
Eosinophils (1.5% of WBC’s) – release granules of enzymes to kill parasites
Natural Killer Cells – destroy infected cells and tumor cells by breaking open their cell membranes with a secreted enyzme
Basophils and Mast Cells – release histamine in response to physical damage or damage by microorganisms – Causes an inflammatory response

7. Inflammation
Histamine increases blood flow to an area by dilating the pre-capillary arteries and constricting the venules
Increases the permeability of bv so immune cells can get into the tissue
Blood leaks into the area causing redness and swelling
Clotting factors activate and complement attracts macrophages
Pus – dead WBC’s and fluid leaked from the bv.
Widespread inflammation – causes low blood pressure and high fever (some inflammatory cells release pyrogens that reset the brain’s thermostat) – can die of septic shock

8. Non-Specific Immunity - Proteins
Chemokines or Cytokines – released from damaged cells or other immune cells
Bind to receptors on immune cells – attract them to the area or activate them
Cause neutrophils to be released from the bone marrow
Cause monocytes to produce NO
Cause basophils to produce histamine
Etc.

9. Proteins Continued
Complement – 20 proteins (both specific and non-specific)
Non-specific – attracts phagocytes, coats bacteria making it easier to phagocytize, binds to basophils and mast cells causing release of histamine and inflammation
Specific - Binds to 2 Ab bond to antigen and causes lysis of invaders
Interferon – produced by virus infected cells – makes nearby cells resistant to virus infection
Interleukins – activate other immune cells

10. Specific Immunity Uses Specific Antigens
Activity Immunity – your own immune system responds
Pasive Immunity – transfer of antibodies
Rabies Treatment
Mother’s Milk
Humoral – antibodies (proteins) – can only attack free pathogens in the blood
Cell Mediated – can only attack cells infected with pathogens and cancer cells

11. General Information about Specific Cell Mediated Immunity
Primary response – takes 5-10 days for a maximum response against a specific antigen
Secondary response – takes 3-5 days for a maximum response (due to memory cells which divide faster and survive longer)
What happens when a T helper cells binds to an antigen on an APC? The cell makes cytokines that cause specific T killer and B cells to multiply
What happens when a B cell binds to an antigen on a free pathogen? B cell secretes soluble antibodies and undergoes mitosis to make more of that B cell
What happens when a T killer cells binds to an antigen on an infected? It makes clones of the T cell and secretes perforin to kill the infected cell

12. MHC MHC = major histocompatibility complex
Marker proteins on the cell’s surface for immune recognition
200 MHC molecules
Class I MHC – on all cells
Class 2 MHC – on macrophages, B and T cells

14. T cells
T - Helper cells
CD4 cells (part of receptor)
Recognizes antigen and MHC class II (APC’s)
When binds to APC, makes cytokines that act on B and T cells (causes them to multiply and activate)
T – Killer cells (cytotoxic T cells) – Steps of Activation
1. Pathogen is eaten by a macrophage (Antigen Presenting Cell or APC)
2. APC digests the pathogen and displays antigens on MHC class II
3. T-helper binds and get activated – makes cytokines to activate T killer cells – only activates T killer as shown below
4. CD8 cells (part of receptor)
Recognizes infected or cancerous cells because they are displaying antigen on MHC class I (binds to the infected cells)
Releases enzymes that punch holes in the infected cell’s membrane
Cell explodes releasing pathogens
Pathogen no longer has a place to reproduce – antibodies pick it up or macrophages eat it
Immunology You Tube Video

16. Infected Cell

17. Steps of B cell activation
B cells
Has antibodies embedded in membrane as receptors / secretes Ab in soluble form when activated
Steps of B cell activation
Pathogen is eaten by a macrophage (Antigen Presenting Cell or APC)
APC digests the pathogen and displays antigens on MHC class II
T-helper binds and get activated – makes cytokines to activate B cells
B cells bind to antigens on free pathogens that match the shape of their receptor (membrane antibodies)
Only the B cells that bind to antigen get activated by the cytokines – become plasma cells (make 2000 Ab/sec and memory cells (can multiply faster the second time)

18. Antibody Structure Variable Region makes different 3-D binding sites
It is made up of three differerent regions:
Variable region – 400 different choices
Diverse region – 15 different choices
Joining region – 4 different choices
1 billion different shaped antibodies

19. B cells also become APC’s when activated and further activate T helpers which produce more cytokines to activate the B cells more

20. Antibody Functions
Bind to antigen (neutralization) – may block the activity (block virus from binding to a host cell, etc.)
Clumping or coating bacteria (opsonization) – makes it easier for macrophage to engulf
Activates complement which punches holes in the cell membrane of bacteria