Transplants Flashcards
1
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A
2
Q
The Immune System
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- Defense, homeostasis & surveillance
- Multifaceted response to attack from outside (pathogens) and inside (neoplasms)
3
Q
Three Phases - Immune systeme
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- Recognition of the substance as non-self
- Proliferation of immunocompetent cells
- The effector phase or action against theforeign substance
4
Q
Innate Immunity
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- What we are born with – genetically based
- NonspecificMultiple cell types & chemical regulators
- First line of defense against non-self
- No memory
- Surface barriers
- Normal flora
- White blood cells – leukocytes
- Complement
- Chemokines
5
Q
WBC’s or Leukocytes
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- 5,000 – 10,000 WBC’s per mm3
- Act like independent single-cell organisms
- move & can capture things on their own
- Produced in the bone marrow
- All recognize self & non-self
6
Q
Antigen
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- A substance capable of eliciting an immune response
- Antigens on the surface of cells that are genetically predetermined by a series of like genes.
7
Q
Lymphocytes – B Cells
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- Responsible for the production of antibody or immunoglobulin
- Primary purpose is to mark an antigen for destruction by the immune system.
8
Q
Macrophages
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- FIXED – concentrated in lungs, liver, lymph nodes, spleen, brain microglia, kidney mesoangial cells, synovial cells & osteoclasts
- WANDERING – roam the blood vessels– can leave them to go to an infection site (extravasation)
- Once they digest they place some of the proteins on their surface – antigen presentation
9
Q
T Lymphocytes
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- Produced in bone marrow – mature in thymus
- All have CD3 & Ag specific T cell receptors (TCR)o
- Cellular immunity
- Killer T cells – CD8+
- Helper T cells– CD4+
- Suppressor T cells
- Memory T cells
10
Q
B Lymphocytes
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- Produced in bone marrow & mature there
- All have Ag specific Immunoglobulins (Ig) on surface
- Humoral immunity – produce antibodies
- Memory cells circulate
11
Q
CD4 + T Helper Cells
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- Recognize antigen processed & presented in association with HLA class II
- Presentation takes place in lymphoid tissue – spleen, lymph nodes
- Specific receptors on T helper cells bind to the Ag:HLA class II complex
- T helper cell becomes activated
12
Q
CD8 + T killer Cells
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- Recognize Ag presented with HLA class I molecules – Ag that has been synthesized within the cell (i.e.: virus)
- Recognition of APC by T killer cells usually results in death of the APC
- Fulminant hepatitis (HBV) – liver damage caused by T killer cells
13
Q
Cluster of Differentiation: (CD)
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- > 160 clusters – each cluster is a different molecule that coats the surface
- Found on lymphocytes
- 100,000 molecules on every T & B cell
- Huge variability in antigen receptors
- CD4+ = T helper cells
- CD8+ = T killer cells
14
Q
A
15
Q
Human Leukocyte Antigens (HLA)
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- Proteins found on the surface of almost every cell (except erythrocytes) o
- Form the basis for self- recognition o
- Bind antigen pieces for presentation to T cell receptors (TCR’s)
16
Q
HLA Class I
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- Found on every nucleated cell in the body
- HLA-A, -B, and -C
- Recognized by CD8+, T killer cells
- Bind fragments of foreign proteins that are produced inside the cells
- Antiviral, antitumor and acute graft rejection
17
Q
HLA Class II
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- Only found on antigen presenting cells
- HLA-DR, -DQ, and -DP
- Macrophages, dendritic cells, B cells
- Recognized by CD4+, T helper cells and by T suppressor cells – regulators of immune response
- Bind fragments of foreign proteins that have been proteolytically degraded by APC’s
18
Q
B Cells
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- B cells clone and differentiate under the influence of Th2 produced interleukins 4 and 5
- B cells change morphology – no longer have Ig on surface
- Become plasma cells that produce Ab in vast quantities
- Ab binds to Ag – targeting these cells for destruction
19
Q
B Cells – Humoral Immunity
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- B cells become plasma cells which produce
- vast quantities of antibodies specific to Ag
- Antibodies circulate in the blood & lymph – the body’s “humors”
- B cells can also present Ag to Th cells
- Some return to lymph tissue to remember & wait for the next attack
20
Q
Five types of antibodies
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- IgG – the main type in circulation, binds to pathogens, activates complement, and enhances phagocytosis
- IgM – the largest type in circulation, activates complement and clumps cells
- IgA – found in saliva and milk, prevents pathogens from attaching to epithelial cells in digestive and respiratory tracts
- IgD – on surface of immature B cells, its presence signifies the readiness of a B cell
- IgE – found on basophils in blood and on mast cells in tissues. Responsible for immediate allergic response and protection against certain parasitic worms
21
Q
Cellular immunity
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- CD4+ T helper cells
- Th 1 – release –> IL-2 –> T helper & killer cells
- CD8+ T killer cells
- Cytokines
22
Q
Hummoral Immunity
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- B cells – Plasma cells
- Antibodies
- Complement
23
Q
Transplantation Immunology Applied
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- Goal is to replace diseased organs with healthy organs to save & prolong life
- Once replaced, the goal is to protect the foreign organ from the host’s immune system