1. Immune System How we stay alive though vastly outnumbered

2. The Immune System – (the big picture)
Innate (Nonspecific) Immunity
Response is localized…
Inflammation is hallmark
No ‘customizing’…
No memory…
OYO – Great summary in Tables 21.1 & 21.2, 21.3
Adaptive (Specific) Immunity
Response is systemic…
Is customized (specific)…
Has memory…
Great Summary Table 21.8, 21.4
Fig 21.1

3. OYO

4. OYO

5. OYO

6. Adaptive Immunity (an outline)
Antigens
Immunocompetence & Self-tolerance
Positive vs. Negative selection of B cells and T cells
Antigen-Presenting Cells (APCs) needed to activate CD8 T cells and Helper T cells which then activate both B cells and T cells
The Humoral Immune Response by B cells
The Cellular Immune Response by T cells
Vaccinations
Organ Transplants & Rejections
HIV & AIDS
Autoimmune Diseases
Hypersensitivities

7. Great summary of B cells vs. T cells

8. Antigens and antigenic determinants
Fig. 21.7
Most antigens
have several.
Lg. proteins may have 100s

9. Immunocompetence
Fig. 21.8 Ts Bs Ts Bs Ts Ts Ts Bs

10. Positive & Negative Selection
Fig. 21.9
Self MHCs = major histocompatibility complexes …
Receptor shapes (binding sites) on new B & T cells are random …
Some “read” (connect) to self MHCs, some don’t
1) If read self MHC… positive selection
If can’t read … apoptosis
2) If read self MHCs & react to those with self antigen… negative selection
Survivors (approx. 2%) are “self tolerant” and therefore immunocompetent and self-tolerant

11. Immunocompetence
Fig. 21.8
Lymph node
“gauntlet” Bs Ts

12. Lymph nodes as check points

13. Lymph node interior
Fig. 20.3

14. APCs - Antigen Presenting Cells
Phagocytize the foreign antigen
Present the foreign antigenic marker at surface
Are needed to activate CD4 helper Ts and CD8 cytotoxic Ts
Are not needed to activate B cells but do enhance activation via helper Ts
Examples:
Dendritic cells of skin. #1
Macrophages in lymph nodes, spleen, and connective tissues
Some B lymphocytes – but only to activate CD4 Helper Ts
Dendritic cells, after phagocytizing antigen, move into lymph and “present” antigen to T cells in lymph nodes

15. Humoral Response - B cells
Fig
5 days
5 days
2000/sec/cell
Location…
Activation…
Cloning…
Plasma cells…
1-2 days

16. Humoral response (antibodies) effective against extracellular antigens

17. Actions of antibodies Fig. 21.15
Video of neutrophil chasing bacteria, 15 secs

18. Humoral Response - B cells
Fig
5 days
Memory cells…
1o vs. 2 o response
Vaccines
5 days
1-2 days

19. Primary vs. Secondary Response
Fig

20. The Cell-Mediated Response - T cells
Fig. 20.2

21. Two major types of T cells
Fig

22. Action of CD8 cells (a.k.a. cytotoxic Ts, TC, Killer Ts)
Fig
Perforin and granzymes…
Video of Killer attacking cancer cell, 1 min

23. Cell-mediated T cell response is effective against intracellular antigens
And against antigens that are cellular themselves.
E.g.
Bacteria
Cancer cells V
V V
V V
V V

24. B cell antibodies against extracellular antigens
Bs and Ts work together simultaneously
B cell antibodies against extracellular antigens
T cells attacking intracellular antigens

25. Central role of helper Ts
Fig

26. Good Summary Fig. 21.20 and Table 21.8

27. AIDS due to HIV
AIDS = Acquired Immune Deficiency Syndrome
HIV = human immunodeficiency virus
Reduces the # of helper Ts (CD4)
Helper Ts play a central role in activation of both B cells & T cells
Therefore both responses are suppressed
Pt. now vulnerable to infections – pneumonia, TB, cancer, etc.
Helper T #s determined by CD4 count
Normal = 600 – 1200 cells/uL
Aids pts. typically less than 200 cells/uL

28. Antibiotics
Chemical substances…
Effective against bacteria
Similar to cytokines (including interferons and interleukins)
Is actually a form of chemotherapy

29. Tissue Transplant Rejections
Why?
Who?
Prevention?
Immunosuppressive drugs
Advantage?
Disadvantage?

30. Autoimmune Disorders
Def…
E.g. Myasthenia Gravis
Rheumatoid arthritis
Multiple Sclerosis
Lupus

31. Hypersensitivites = Allergic Reactions
When…
Your immune reaction is the problem
Antigens now called “Allergens”
Types of Hypersensitivities are determined by
time frame of reaction – immediate vs. delayed
Whether antibodies (B cells) or T cells are involved
Antibodies cause immediate and subacute reactions
T cells cause delayed reactions

32. Acute (immediate) Hypersensitivity Reactions
Fig
Primary response of both B & T cells
IgE antibodies from B cells attach to and act as receptor sites on mast cells and basophils.
Usually asymptomatic at this point
[Mast cells abundant in skin and mucous membranes]
Granules contain and release histamine
Therefore…..
Upon 2nd exposure reaction begins within seconds of exposure
E.g. Asthma

33. If this response is localized…
mostly just a nuisance
S&S depend upon method of exposure
Usually inhaled or ingested

34. 1A) If allergen is airborne (inhaled)…
1A) If reaction includes spasms of airways and mucus plugs = asthma
S&S:
SOB
Wheezing
Hypoxia
Cyanosis

35. 1B) If allergen is ingested…
Fig. 23.1
Includes some food allergies
Cramping
Vomiting
Diarrhea

36. Trtmt
Localized reactions respond well to antihistamines.
Bronchodilators (e.g. albuterol, epi) are beneficial for asthma.

37. 2. If response is systemic …
Called Anaphylactic Shock (a.k.a. anaphylaxis)
Is life threatening
most often due to an injected allergen (but may also be ingested)
Blood transports it to all mast cells & all basophils causing massive release of histamine

39. 2. If response is systemic (cont’d)…
Effects:
Tongue swells & bronchioles constrict SOB
Hives
Vessels dilate, BP falls
Vessel permeability increases, fluid shifts out of vessels, BP falls further
Trtmt: Epinephrine
- To dilate bronchioles and vasoconstrict vessels

40. B) Delayed Hypersensitivities
Begins 1-3 days after exposure
The allergens (now called Haptens) pass through skin and attach to “self” (MHC1) markers.
Your cells now appear foreign
1) Macrophages activated by cytokines come for a “feeding frenzy”
2) T cells come & destroy
Most examples are called “Allergic Contact Dermatitis”
(cosmetics, soaps, deodorants, some metals, poison ivy, poison oak, TB test)

41. B) Delayed Hypersensitivities
e.g. cosmetics

42. Poison ivy
Antihistamines not effective
Need corticosteroids (e.g. Prednisone)

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