Immunology- intro Flashcards
1
Q
what is immunology?
A
the study of the immune system and its responses to various insults
1
Q
give 6 reasons why immunology is important/applicable
A
- defense against pathogens
- herd health (via serodiagnostics and vaccination)
- exaggerated or deficient responses (immune-mediated disease and immunodeficiences)
- cancer therapy
- grafts
- research tools
2
Q
what are 5 hallmarks of the adaptive immune system?
A
- timing (activated later than innate)
- specificity
- diversity
- memory
- self vs nonself discrimination
3
Q
what is the innate immune system?
A
the part of the immune system that is in place at birth, somewhat non-specific, and responds immediately to an offense, and is present in all animals
4
Q
what are the 3 components of the innate immune system?
A
- physical/physiologic barriers
- antimicrobial molecules
- sentinal/phagocytoc cells
5
Q
what are the 4 physical/physiologic barriers of the innate immune system?
A
- epithelium
- mucus/tears/sebum
- flushing/peristalsis
- commensal flora
6
Q
how does epithelium act as a physical barrier in the innate immune system?
A
the stratified squamous epithelial layer has tight junctions to keep out pathogens from skin and is constantly sloughing old cells to remove potential pathogens
7
Q
how do mucus/tears/sebum function in innate immunity?
A
- pH
- lysozyme
- bile
- pancreatic enzymes
8
Q
how does flushing/peristalsis function in innate immunity?
A
cilia beat to clear the respirator tract of pathogens and the GI tract moves pathogens out via peristaltic contractions
9
Q
what are two examples of antimicrobial substances and what are they produced by?
A
- defensins
- cathelicidins
produced by epithelial cells and leukocytes
10
Q
describe how defensins and cathelicidins work
A
they are amphipathic and insert themselves into one half of the lipid bilayer, forming a pore that results in cell death bc cells don’t like having holes
11
Q
what are 4 functions of the antimicrobial substances of the innate immune system?
A
- direct toxicity to bacteria, fungi, viruses, protozoa, enveloped viruses, and tumor cells
- activate/recruit leukocytes
- bind/neutralize lipopolysaccharides and microbial toxins
- stimulate wound healing and vascularization
12
Q
what are opsonins?
A
extracellular molecules that bind to microbes and make microbes more susceptible to phagocytosis; an intersection of adaptive and innate immunity
13
Q
give 2 types of opsonins
A
- complement proteins
- mucosal antibodies from IgM, IgA, and IgG
14
Q
what are the 3 sentinel cells?
A
- mast cells
- macrophages
- dendritic cells
15
Q
what do mast cells do? where are they located
A
located at blood vessels in tissues, secrete granules to initial inflammation
16
Q
where are macrophages located? what do they do?
A
located in tissues, also kickstart inflammation (like mast cells) but also do phagocytosis
17
Q
what do dendritic cells do?
A
process antigen to start adaptive response, basically pick up/phagocytose and then leave to coordinate additional efforts in the response
18
Q
where do immune cells come from?
A
hematopoiesis that occurs in the bone marrow
19
Q
what are the 3 categories of cells produced by hematopoiesis in the bone marrow?
A
- erythroid
- myeloid
- lymphoid
20
Q
what are erythroid cells?
A
red blood cells
21
Q
what are myeloid cells? (4)
A
- granulocytes
- mast cells
- monocytes/macrophages
- myeloid dendritic cells
22
Q
what are lymphoid cells? (2)
A
- T and B cells
- natural killer cells (NK)
23
Q
what is the ONLY self-renewing cell in bone marrow?
A
multipotential hematopoietic stem cells/ hemocytoblasts
24
at what point are cells committed to their path in bone marrow?
when they differentiate from multipotential hematopoietic cells to either common myeloid progenitor cells or common lymphoid progenitor cells
25
what cells comprise the major of innate immune cells as well as other cells?
those derived from common myeloid progenitor cells
26
what 11 cells derive from common myeloid progenitor cells?
1. megakaryocytes
2. thrombocytes
3. erythrocytes
4. mast cells
5. myeloblasts
6. basophils
7. neutrophils
8. eosinophils
9. monocytes
10. macrophages
11. myeloid dendritic cells
27
what cells derive from common lymphoid progenitor cells? (4)
1. natural killer cells (large granular lymphocytes)
2. small lymphocytes (T and B cells)
3. plasma cells
4. lymphoid dendritic cells
28
describe where maturation of monocytes takes place
these cells are born in the bone marrow, and differentiate into monocytes, then migrate to lymphoid tissue or peripheral tissue where they are either activated to macrophages or differentiated to other cells
29
what are 4 cells types that monocytes can differentiate into?
1. microglia
2. kupffer cells in the liver
3. alveloar macrophages in the lungs
4. osteoclasts
30
describe maturation of dendritic cells
common dendritic cell precursors leave the bone marrow and migrate to the blood where they differentiate into either preconvential DCs or plasmacytoid Dcs, which will then enter lymphoid tissue or peripheral tissue and differentiate into conventional DCs or plasmacytoid DCs
31
where do lymphocytes develop?
bone marrow
32
where do lymphocytes mature?
the generative lymphoid organs
B cells: Bursa of Fabricius (bird), bone marrow (mammals)
T cells: thymus for everyone
33
what happens to mature, but naive B and T cells?
circulate through the blood to secondary lymphoid organs
34
what happens to mature naive B and T cells in secondary lymphoid organs?
they may respond to foreign antigens in these secondary lymphoid tissues or return by lymphatic drainage to the blood and recirculate through other secondary lymphoid organs
35
how are myeloid cells defined?
1. morphology: cell shape (round vs irregular) and shape of nucleus (round vs multilobed)
2. granule staining
36
what myeloid cells take up eosin stain?
eosinophils
37
what myeloid cells take up hematoxylin stain?
basophils and mast cells
38
what myeloid cells have little dye uptake?
neutrophils
39
how can we monitor hematopoiesis?
neutrophils! mature neutrophils have lobulated nuclei; if hematopoiesis has increased and more newer neutrophils are being pumped out, will see what is called a left shift, where more immature neutrophils are present (less defined lobular nuclei)
40
what cell makes up a majority of circulating leukocytes?
neutrophils
41
how long do neutrophils live?
short lifespan just a few days
42
what is are neutrophils referred to as in terms of their response time?
first responders that aren't in the tissue; show up a little later but the first circulating cells on the scene
43
describe the morphology and granule staining of neutrophiles
multilobular nucleus with pale staining granules and round shape cell
44
what is the primary function of neutrophils and give 3 ways they accomplish this
kill infecting microbes via
1. phagocytosis
2. degranulation
3. neutrophils extracellular traps (NETs)
45
give 6 granule contents of neutrophils and what they do
1. lysozyme: bectericidal
2. defensins: bactericidal
3. lactoferrin: binds iron
4. collagenase: degrades bacteria and tissues
5. elastase, cathepsin B, and beta glucorinidase: degrade connective tissue, bactericidal, and activate TNF-alpha
6. myeloperoxidase: respiratory burst
46
what do rabbits, hamsters, guinea pigs, reptiles, birds, amphibians, and some fish have instead of neutrophils?
heterophils
47
what do bird heterophils lack compared to neutrophils?
lack significant myeloperoxidase activity
48
describe NETs
1. an active process in which nuclear contents extruded
2. these contents are DNA coated with histones and granule components that are very sticky
3. they capture microbes, kill them, and destroy virulence factors
4. abundant at sites of inflammation
49
what percent of all leukocytes do eosinophils make up after release from the bone marrow?
0.1-3%
50
from blood, where do eosinophils go?
exit blood and hang out in connective tissue
51
describe morphology and granule staining of eosinophils
round shape; round to multilobular nuclei; brightly eosinophilic
52
what is the primary role of eosinophils? how do they do this?
kill multicellular parasites (helminths) by releasing granules
53
what response do eosinophils play a role in?
allergic responses
54
what percent of circulating granulocytes do basophils make up?
less than 0.5%
55
describe morphology and granule staining of basophils
round cell shape; multilobulated nuclei; granules deeply basophilic
56
what do basophils and how do they get there?
promote a Th2 response by migrating into tissues during multicellular parasite infections and late phase allergic reactions
57
what are monocytes?
circulating precursors of macrophages and DCs that enter tissues to differentiate
58
what percent of circulating leukocytes do monocytes make up?
2-10%
59
describe morphology and granule staining of monocytes
irregular shape cell but larger than other granulocytes; nucleus is round-bean shaped; cytoplasm is pale basophilic with vacuoles
60
what is the function of monocytes? how accomplish?
respond to inflamed tissues;
1. can phagocytose
2. can produce cytokines
61
where do macrophages come from?
arise from monocytes that exit circulation
62
what determines the morphology and function of macrophages? (2)
1. tissue factors
2. cytokines
63
describe the general morphology of macrophages (although tissue factor and cytokine dependent of course)
large, amoeboid shape with a round nucleus; pale basophilic with vacuolated cytoplasm
64
what are 3 functions of macrophages?
1. sentinel cells if already in place in tissues that produce cytokines when activated
2. phagocytosis
3. antigen presentation
65
where do dendritic cells develop from?
monocytes
66
where are dendritic cells found?
typically in connective tissues
67
describe morphology and granule staining of dendritic cells
dendrite like processes; round nucleus; clear cytoplasm
68
what are the 3 functions of dendritic cells? highlight the hella important one
1. sentinel cells
2. endo/phagocytosis
3. ANTIGEN PRESENTATION
69
where are mast cells found?
in connective tissues near blood vessels and nerves
70
describe morphology and function (4) of mast cells?
round cell, round nucleus, fine, basophilic granules
1. vasodilation
2. vascular permeability
3. recruit other leukocytes
4. allergic responses aid
71
what are 4 functions of mast cells?
1. vasodilation
2. vascular permeability
3. recruit other leukocytes
4. allergic responses
72
describe natural killer cell lineage and why it is special
lymphoid lineage but don't need prior sensitization and don't express T or B cell receptors
73
where do NK cells mature?
in secondary lymphoid organs
74
what percent of circulating lymphocytes are4 NK cells?
15%
75
describe morphology and granule staining of NK cells
larger than other lymphocytes; round nucleus; fine, azurophilic granules
76
what is the function of NK cells? how?
1. first line of defense against viruses and some tumors
2. secrete cytotoxic granules that drive apoptosis
77
give whether a problem is indicated to be chronic or acute based on presence of neutrophils, macrophages/lymphocytes/plasma cells, or both
neutrophils: acute
macrophages/lymphocytes/plasma cells: chronic
both: chronic, but active
78
what does the presence of neutrophils tell you about the potential cause of a problem?
extracellular bacteria
79
what does the presence of macrophages tell you about the potential cause?
intracellular bacteria/parasites, fungi, foreign body
80
what does the presence of eosinophils tell you about the potential cause?
extracellular parasites, allergy
81
what does the presence of mast cells/basophils/eosinophils tell you about the potential cause?
allergy
82
what does the presence of lymphocytes/plasma cells tell you about the potential cause?
viral, immune-mediated
