Immune (addition to MCAT bio immune) Flashcards
(94 cards)
1
Q
Purpose of skin
A
- -innate immunity
- -pH is low in sweat so inhibits growth of microorganisms on skin
- -antibodies from in-body secretions move to surface to bind invaders
2
Q
Mechanisms of protection for body openings
A
- Respiratory system - roaming macrophages, mucus traps invaders and moves it out by cilia
- Urogenital tract - maintains a level of acidity to protect against invaders
- Digestive tract - Peyer’s patches absorb bad agents
- Throat tonsils - surround the throat with organized immune cells that act as a lymphoid barrier to protect against invaders
3
Q
Throat tonsil types
A
- Pharyngeal - located at back of throat, just past nasal opening
- Palatine - located on either side of throat/tongue (swollen with strep)
- Lingual - located at back of tongue
4
Q
1st line of defense (innate, nonspecific)
A
- Skin
2. Protection of various openings
5
Q
2nd line of defense (innate, nonspecific)
A
- Lymph system
- Spleen
- Blood stem cells
- Phagocytic cells
- Natural killer cells
- Interferons
- Pyrogens –> fever
- Complement system
- Inflammation
- Toll-like receptors
11, Non-specific ID-card model
6
Q
Immune surveillance
A
- -the process of catching early cancers/issues
- -done by the lymph system
7
Q
Lymph system
A
- -innate and nonspecific
- -removes excess fluid from tissues
- -acts as a checkpoint to catch invaders
8
Q
lymphedema
A
–when you remove lymph nodes, water builds up in that area –> swelling
9
Q
left subclavian vein
A
–the location where the fluid that passes through lymph is returned to blood circulation
10
Q
spleen
A
- -innate and nonspecific
- -stores extra white and red blood cells
- -acts as a “checkpoint” to scan for invaders. Basically acts as a large lymph node.
11
Q
blood stem cells
A
- -innate and nonspecific
- -RBCs and WBCs all made from bone marrow
12
Q
granulocytes
A
- -eosinophils
- -basophils
13
Q
EPO
A
–stimulates bone marrow to make RBCs and WBCs
14
Q
aplastic anemia
A
–condition in which bone marrow stops working
15
Q
erythrocytes
A
–red blood cells
16
Q
leukocytes
A
- -white blood cells
- -includes all immune cells (basophils, lymphocytes, etc)
17
Q
phagocytic cells
A
- -nonspecific cells
- -neutrophils
- -monocytes
- -macrophages
18
Q
diapedesis
A
–the process of immune cells leaving the circulation to enter tissue spaces to combat invaders
19
Q
neutrophils
A
- -part of nonspecific response
- -most common type of white blood cell
- -phagocytic
- -kills itself after eating bacteria
- -release their DNA to create nets when they die to trap more invaders
- -secrete cytokines as they die
- -secrete oxygen radicals as they die
20
Q
monocytes
A
- -nonspecific
- -phagocytic
- -contains large horseshoe-shaped nucleus
- -turn into a macrophage once it gets into tissues
21
Q
macrophage
A
- -nonspecific
- -phagocytic
- -Found only in tissues, not circulating in blood
22
Q
Natural killer cells
A
- -nonspecific
- -recognizes a non-self and kills it
- -Releases protein perforin that pokes holes in invader cell membrane to kill it
- -Releases granzymes in the invader that target cell’s nucleus to reprogram DNA and cause invader cells to do apoptosis
23
Q
Interferons
A
- -nonspecific response
- -proteins secreted by virally infected cells to warn other cells around it
- -Signal to produce more T-cells
- -A type of cytokine
- -Response of surrounding cells: reduce transcription and shorten half life to inhibit virus replication and proliferation
24
Q
Temperature response
A
- -nonspecific response
- -Pyrogens cause fever –> body temperature increases
25
exogenous pyrogens
- -contained in bacterial cell wall
| - -cause fever when ingested
26
endogenous pyrogens
- -hypothalamus controls body temp
| - -internal pyrogens can reset body's normal point so it maintains a higher body temp
27
Complement system
- -nonspecific response
- -proteins in the blood assemble into a "membrane attack complex" (MAC) that pierces a hole into membrane of invader
- -C3 protein is most important protein of the complex
28
Inflammation
- -nonspecific response
- -sign of warning cells and early immune cells on the scene
- -cytokines release histamines that cause redness, swelling
29
toll-like receptors
- -nonspecific
- -dont know how they work exactly
- -release cytokines to warn other cells of immune attack
30
3rd line of defense
- -All adaptive immunity, VERY specific
1. Lymphocytes
a. T-lymphocytes
b. B-lymphocytes
31
antibodies
- -proteins with binding sites for specific molecules called antigens
- -always Y-shaped with 2 antigen-combining sites
- -recognize a specific epitope
32
epitope
- -the part of the antigen to which the antibody attaches
| - -a single antigen can have many different epitopes, so a single antigen can be recognized by many different antibodies
33
T-lymphocytes
- -These are responsible for "cell-mediated immunity" part of adaptive/specific immune response
- -educated in the thymus
- -like other lymphocytes, nucleus takes up most of cytoplasm
- -Gets a lot more cytoplasm when it gets activated
34
Types of T-lymphocytes
1. Helper T-cells
2. Inducer T-cells
3. Cytotoxic T-cells
4. Suppressor T-cells
35
Helper T-cells
- -work with other cells to make the immune response more efficient
- -Has CD4 marker
36
Inducer T-cells
- -stimulate replication of more T-cells
| - -CD4 marker
37
Cytotoxic T-cells
- -these are the killing cells of the cell-mediated immunity
| - -CD8 marker
38
Suppressor T-cells
- -turn down immune response
| - -Unknown whether CD4 or CD8
39
B-lymphocytes
- -associated with "humoral" or "antibody" specific response
- -make and secrete antibodies
- -educated in the periphery (i.e. no particular organ associated with education)
- -See a huge increase in rough ER when they are activated (in order to make lots of proteins/antibodies)
- -Called a plasma cell when activated
40
MHC markers
- -set of cell surface proteins essential for the immune system to recognize self vs. foreign molecules
- -These are hugely polymorphic and they can present all sorts of things in their groove
- -Vary a lot between individuals but not within an individual - this makes it difficult to find an exact donor match
- -coded for on chromosome 6
41
Class 3 MHC markers
--complement proteins
42
Class 2 MHC markers
- -found on macrophages, B-cells, some T-cells
- -structure: 1 alpha and 1 beta component side by side in lipid bilayer
- -groove at top to "present an antigen"
- -Known as APC's - antigen presenting cells
--these present external antigen in immune response
43
Class 1 MHC markers
- -found on all nucleated cells, including immune cells
- -NOT found on RBCs (b/c RBCs not nucleated)
- -structure: 1 large segment is called the "heavy chain" and the smaller segment is called the "beta-2-microglobulin"
- -heavy chain is embedded in cell membrane and beta-2 segment is attached just to heavy chain
- -these present internally synthesized molecules in their groove
- -Normally these would be presenting "self" antigens in their groove, but if cell has been infected by a virus and is replicating the viral genome, the MHC1 markers will be presenting "viral" antigens in their groove, to which immune system responds
44
Types of transplants
1. Autologous
2. Heterologous
3. Allogenetic
45
Autologous transplant
- -Get your own tissue
| - -No issue w/ matching MHC markers
46
Heterologous transplant
- -get someone else's tissue with matched MHC markers
| - -usually from family members
47
Allogenetic
- -someone else's tissue with unmatched MHC markers
| - -success depends on what type of transplant
48
what type of transplant does not need a match b/w donor and recipient?
cornea
49
graft vs. host disease
- -new bone marrow will make immune cells that don't match the rest of the body cells
- -new immune cells attack the body
- -This can be fatal
50
Initial response to infection
1. Phagocyte mobilization
- -immune cells squeeze between cells (extravasation) and move from bloodstream into tissue (diapedesis)
- -inflammatory chemicals act as positive chemotactic agents, telling immune cells to come toward that location
- -neutrophils begin eating up invader
51
Second step in response to infection
2. Monocytes move into tissue, convert to macrophages, phagocytize invader
- -Macrophage fuses the invader with a lysosome and digests invader
- -Puts a small peptide fragment from invader into the groove of macrophage's MHC2 marker
- -macrophage acts as antigen presenting cell
52
Third step in response to infection
3. More nonspecific responses
- -Interferons released - alpha and gamma
- -secrete other cytokines including interleukin-1
53
interferon types
1. alpha interferon: warning signal and stimulates NK cells
| 2. gamma interferon: stimulates monocytes to make more macrophages
54
interleukin-1
--an endogenous pyrogen
55
Fourth step in response to infection
4. T-cell recognition and actions
- -Helper T cell is MHC2 restricted, meaning it only can recognize the antigen when it is presented in the MHC2 groove
- -Helper T cell recognizes antigen in MHC2 marker and attaches to it macrophage with the help of the CD4 protein as a co-receptor
- -Helper T cell can now secrete macrophage inhibition factor, interleukin-2, inducer T-cells
56
macrophage inhibition factor
- -traps macrophages at the scene of the invader
| - -secreted by helper T cells after they have recognized antigen in MHC2 groove
57
interleukin-2
- -T-cell growth factor - stimulates replication of bound T cells
- -secreted by helper T cells after they recognize antigen in MHC2 groove
58
inducer T-cells
- -signal for more T-cells
| - -activated by helper T-cells in response to recognizes antigen in MHC2 groove
59
clonal selection
- -the mechanism by which only T-cells that attack foreign substances proliferate
- -the process of "educating" lymphocytes
60
5th step in immune response
5. Activation of 2 arms of the immune system: cell-mediated immunity (T-cell) and humoral/antibody immunity (B-cell)
61
Cell-mediated immunity
- -carried out by cytotoxic T-cells
- -When helper T-cells release IL-2, it stimulates cytotoxic T-cells to replicate
- -Tc cells have a receptor fitting the specific antigen presented by the APC, allows Tc cells to bind more MHC-antigen complexes and attack
- -memory Tc cells also made for future responses
62
Antibody immunity
- -carried out by B-cells
- -B-cell binds antigen, chews it up, displays it on surface of MHC2
- -IL-2 signal is what triggers B-cells to divide/proliferate and turn into plasma cells (IL-2 is released by helper T-cells when they bind MHC2-antigen complex)
- -Plasma cells are the antibody producing cells
- -memory B-cells are made for future response
63
T-cells versus B-cells
- -B-cells can pick up free antigens floating around
| - -T-cells can only see the MHC-antigen complex
64
Helper T-cells are crucial because
--they activate both arms of the adaptive immune system: cell-mediated and antibody response
65
Antibody functions
1. increase rate of phagocytosis
2. increase attack by complement system
3. increase attack (lysis) by NK cells
66
Opsonization
--the process of enhancing phagocytosis by marking it with an antibody
67
Secondary response
--much quicker and stronger response to exposure as a result of memory B-cells and T-cells
68
HIV
--targets CD4 Helper T-cells, which knocks out cell-mediated and antibody immune responses
69
Fab
- -antigen binding faction
- -There are 2 antigen binding sites per antibody
- -Each Fab is made of 1 heavy chain and 1 light chain
70
Fc
- -constant fraction
| - -similar sequence from one antibody to the other
71
Hypervariable regions
--where there is the most variation and where specificity is most important for binding of that specific antibody
72
5 classes of antibodies
--This is based on the slight variations in the "constant" regions
1. IgM
2. IgG
3. IgD
4. IgA
5. IgE
73
IgM
- -pentamer shape
- -Can bind many more things and agglutinate whatever it binds to
- -get enhanced phagocytosis due to agglutination
- -Usually first antibody to respond to invader
74
IgG
- -second main actor after IgM
| - -most common Ab
75
IgD
--on surface of B-cells
76
IgA
- -dimer held together
| - -most common Ab in bodily secretions (breast milk, tears, saliva, mucus)
77
IgE
--promotes the release of histamine, which triggers allergic reactions
78
Allergic response
- -hypersensitivity response
- -atypical b/c mostly IgE class antibodies are secreted
- -B cell binds antigen --> B cell turns to plasma cell --> plasma cell secretes IgE --> these bind to mast cells' (granulocytes) surfaces
- -When allergen binds antibodies on mast cell's surface, the mast cell releases histamine and other chemicals
79
Anaphylaxis
- -an ACUTE allergic reaction
| - -rapid
80
Type IV - delayed hypersensitivity
1. Poison ivy
- -takes 2-3 days to develop
- -cell-mediated response
- -CD8 T cells kill affected cells
2. Mantoux tuberculin skin test
- -inject small amounts of tuberculin peptides
- -feel for induration - hardened and raised skin as part of inflammation response
81
Somatic recombination
- -The way we create so many B-cell receptors to recognize possible invaders
- -As B-cells are being produced in bone marrow, each B-cell mixes and matches from its genome the genes that will code for its surface receptor - this is basically DNA splicing
- -V,D, J genes contribute to antibody binding ability
- -C genes contribute to constant region
- -This happens only in B-cells
82
Methods of adding diversity to B-cells even after somatic recombination
1. As B-cell proliferates as plasma cells, there are random mutations that add more variation
2. Splicing mechanism isn't very "clean" so can leave a nucleotide hanging or cut an extra one off
83
Heavy chain genes
Vh
D1-D12
Jh1-Jh4
constant region genes
84
Light chain genes
V
J
Constant region
**Notice there are no D region genes in light chains
85
anergy
- -The process by which T-cells require co-stimulation to be activated
- -Can only occur when there is an additional coreceptor
86
tolerance
- -When you are a newborn and your immune system isn't working very well yet, you can accept a range of tissue types
- -this is called tolerance
87
autoimmune mimicry
--occurs when the foreign antigen and the self antigen are so similar that the T-cell is stimulated to attack both
88
Graves disease
--causes exophthalmia (bug eyes)
89
Diabetes
--beta cells of pancreas attacked by body's immune system
90
Lupus
--causes butterfly rash
91
Myasthenia Gravis
- -with ptosis (droopy eye)
- -targets neuromuscular junctions - acetylcholine receptors
- -thymus abnormalities
92
Scleroderma
- -"hard skin"
- -overproduction of collagen and other possible organ damage
- -alopecia (hair loss)
- -produce auto-antibodies that target centromeres
93
Inflammatory Bowel Disease
--autoimmune
94
Inflammatory bowel syndrome
--not autoimmune
