1. Chapter 43
Immune System

2. Leukocytes
Cover dendritic cells

3. Basics Antibodies Antigen Looks for foreign antigen
Specific to a single antigen
Antigen
Located on the surface of the cell/invader
Multiple antigens on a single pathogen

4. Blood Example Rh factors Positive is dominant over Negative
Erythroblastosis fetalis
Occurs when mom is Rh – and baby is Rh +
First child, not mixing of blood, so both are okay. But with second baby, mom will have antibodies that would attack baby’s blood.
Used to be fatal, but now it can be dealt with
O Neg is the universal donor, AB Pos is the universal acceptor
TEST QUESTION

5. Lymphoid Organs/tissues – adenoids, tonsils, thymus, spleen, Peyer’s patches, appendix
Lymphatic System

6. Immune system has to do three things
1. Recognize non-self Recognize foreign antigens/invaders and attack it 2. Remember non-self After destroying the foreign antigen/invader, you want to remember it just in case if it comes back. 3. Recognize self You need to know who is the “enemy” and who is a “friendly”; if your immune system attacks your own cells, that becomes and autoimmune disorder

7. Innate vs Adaptive immunity
Barrier defenses:
Skin – there are friendly bacteria on your skin that offer some protection
Mucous membranes – only make mucous
Secretions – sweat, tears, saliva (have lysozymes), etc.
Internal defenses:
Phagocytic cells – neutrophils, macrophages
Natural killer cells – look for foreign antigens and cancer cells
Antimicrobial proteins – interferons, complement proteins
Inflammatory response – histamine, cytokines, mast cells, etc. (next slide)
Fever- some fever is good to fight infection, but really high temp is not good because it can denature your proteins!
Adaptive Immunity (later on in this presentation)

8. Inflammatory Response
Histamines and cytokines (signaling molecules) released. Capillaries dilate (vasodilation- direct response to histamine)
Neutrophils digest pathogens and cell debris. Tissue heals.
Antimicrobial peptides enter tissue. Neutrophils are recruited.

9. Recognizing the enemy Toll-like receptors
TLR5- recognizes flagellin (you don’t have flagellin so ATTACK)
TLR4- lipopolysaccharides (component of bacteria, so you don’t have this, so ATTACK)
TLR3- double-stranded RNA (foreign nucleic acids, so ATTACK)

10. Eating the enemy

11. Lymphocytes B cells made in bone marrow T cells made in thymus
Have antigen (antibody generator) receptors which recognize epitopes of foreign antigens

12. Antigen receptors On B Cells
Four chains- two heavy, two light
C region (constant region)
V region (variable region- makes each B cell different)
When the antigen receptor is released, it becomes an antibody

13. Antigen Receptors on T Cells
Similar to B cell receptor, but do NOT release their receptors

14. Making Antigen Receptors/antibodies
40 V genes
X 5 J genes
= Over 200 combinations!!
Light chains and heavy chains also combine differently so even more combinations!

15. Self Markers MHC: major histocompatibility complex
About 20 genes, 100 alleles
On somatic cells
Class I: found on all nucleated cells in the body
Class II: found on cells in the immune system (macrophages, T cells, etc.) and is how they communicate with each other
MHC are usually similar among people who are related to each other, but you can still find people that have similar MHCs who are not related to you (think about transplants or infertilities)

16. Humoral Response

17. What do the antibodies do?
Plasma cells have more…. Ribosomes on the ROUGH ER

18. Immunoglobulins M- first one present on the scene
G- most abundant, passes placenta
A- in secretions, breastmilk
E- allergies D

19. Helper T-Cells

20. Cell-mediated immunity
Sees self and non-self

21. Activating B-Cells

22. Putting it together

23. Another one

24. Remember the Alamo…
Memory cells! Booster shots make more memory cells

25. Passive vs Active Immunity
Active – YOUR ANTIBODIES
You got sick, you fought your own fight and made antibodies
Or you got a vaccine, which helped prep your immune system just in case if the invader comes, but you still made your own antibodies
Passive – NOT YOUR ANTIBODIES
Breastmilk (think IgA) gets passed from mother to fetus
Anti-venom, serums, antibody shots (like when you go overseas)

26. Autoimmune diseases
More common in females than males (why? We don’t know)
Rheumatoid Arthritis
Connective tissue in joints and other organs (heart, lungs) is attacked
Rheumatic heart disease
Heart valves are attacked
Untreated strep infection, body thinks heart valves are strep
Lupus
affect the joints, skin, kidneys, blood cells, brain, heart, and lungs
Graves’ Disease
Over-active thyroid gland
SCID (Bubble Boy)
Little or no immune system
Allergies
IgE; cross-linking triggers release of histamine
Anaphylactic shock – severe allergic reaction, reduce blood flow to brain and heart
HIV/AIDS
Destroys helper T-cells
You don’t die from HIV, you die from another infection because your immune system is compromised
Test question- RHD