innate and acquired immunity Flashcards

1
Q

what is the first barrier of innate immunity

A

integument

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2
Q

how does the skin protect for immunity?

A
  • specialized cells block penetration of most microbial organisms and foreign substances
  • beneficial microbes occupy surface area of integument to provide further barrier to penetration
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3
Q

how does sweat and sebaceous glands secretions provide innate immune protection?

A

they have an acidic pH and include a number of fatty acids and hydrolytic enzymes all of which serve as antimicrobials

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4
Q

what are cells in the body that secrete specialized proteins that have innate immune activity?

A

interferons
complement proteins
mucous secretion
hydrolytic enzymes
proteolytic enzymes

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5
Q

what are interferons?

A

class of proteins that have anti-viral activity

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6
Q

how do complement proteins when activated have innate immune response?

A
  • enhances immune response
  • destroys extracellular pathogens (bacteria)
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7
Q

how do mucous secretion in the respiratory and GI tract have innate immune response?

A

effective at trapping and removing antigen facilitated by ciliated epithelial cells that line specific sites

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8
Q

in the GI tract, what serves to create a hostile environment for foreign microbes?

A
  • hydrolytic enzymes in saliva
  • low pH in stomach
  • proteolytic enzymes in bile and small intestine
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9
Q

what are other innate physical barriers besides skin and how are they effective?

A

hairs of nostrils and sneeze and cough reflex: expels antigens of moderate sizes out respiratory and GI tract

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10
Q

what can impair the physical innate barrier?

A

excess consumption of alcohol, cigarette smoking, use of select drugs

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11
Q

what is the next line of defense if physical innate barriers fail to block penetration of foreign antigen?

A

collection of specialized cells

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12
Q

how do specialized cells aid in immune defense?

A

destroy by ingesting antigens (intracellular killers) or by contacting antigen, releasing toxic mediators to destroy (extracellular killers)

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13
Q

what are the two mechanisms of intracellular killers?

A

endocytosis or phagocytosis

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14
Q

what is the process that occurs if the antigen is at the macromolecular level?

A

endocytosis

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15
Q

explain the process of endocytosis

A
  • occurs via simple invagination of the cellular membrane or via a cell receptor-mediated mechanism
  • Once engulfed, the foreign
    macromolecules are encased in endocytic vesicles that fuse with endosomes (acidic pH) and lysosomes (containing degradative enzymes) to break down the macromolecules.
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16
Q

what is phagocytosis?

A

the engulfment of larger particles (i.e. bacteria) forming a phagosome which will fuse to a lysosome to form a phagolysosome, which via enzyme action degrade the particle

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17
Q

what is an example of phagolysosomes containing toxic mediators that can generate respiratory burst

A

nitric oxide
hypochlorous acid

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18
Q

what are opsonins?

A

collection of proteins that can bind to the target particles and facilitate phagocytosis

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19
Q

what are examples of opsonins?

A

antibodies and select complement proteins

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20
Q

what are the cells that function principally as intracellular killers?

A

polymorphonuclear leukocytes (PMN) and macrophages

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21
Q

what are dendritic cells?

A

specialized weak phagocytic cells found in the tissues

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22
Q

why are PMN also classified as granulocytes?

A

because of their appearance when stained

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23
Q

what are cells of PMN?

A

neutrophils
basophils
eosinophils
mast cells

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24
Q

describe the function of PMN cells

A
  • short life span
  • rich in lysosomes and can generate peroxides and superoxide radicals
  • major players in combating early infections
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25
what is the special type of intracellular killer cell that can engulf large particles and then destroy them?
macophages
26
what is the unique ability of macrophages and what other type of cell can do this too?
they can process the destroyed foreign particles and present their smaller components on their cell surface as antigen presenting cells (APC) dendritic cells
27
why do macrophages have specialized names related to the tissue in which they reside?
because they originate from the blood monocytes and migrate to specific tissues in the body, where they maintain their phagocytic function, but also other functions specific to the tissues in which they reside (i.e. Kupffer cells, microglial cells)
28
what are the secretory proteins called that macrophages and PMN can release?
cytokines
29
what are the extracellular killers?
natural killer cells (NK)
30
what are natural killer (NK) cells?
large granular lymphocytes that are able to lyse abnormal cells (viral-infected or cancer cells), without prior activation
31
what is MHC class I?
special cell surface protein construct that NT survey other nucleated cells in the body for
32
what happens if MHC I molecule is not expressed or is defective?
NK cell docks with the abnormal cell and releases pre-formed toxic mediators that cause the cell to die
33
NK T cells are a special subset of _______
thymus
34
what is thymus?
derived cells that can kill target cells through FAS-FAS ligand interaction
35
true or false: NK T cells can release pro-inflammatory cytokines
true
36
what is the major outcome from the activation of intracellular and extracellular killer cells?
inflammation
37
what are the hallmarks of inflammation?
pain redness heat edema loss of function
38
what is inflammation mediated by?
combination of: - acute phase proteins (C-reactive proteins) - complement - coagulation pathway - cytokines
39
what is the function of the mediators of inflammation?
- alter vascular diameter - increase blood flow - increase vascular permeability
40
describe the clinical concept of a fever
believed to be the body’s attempt to make the infectious site less optimal for a bacterial infection to establish.
41
what are the major contributors of fever response and what are they released by?
cytokines IL-1 IL-6 TNF-a released by macrophages
42
true or false: innate immunity has receptor-specific recognition capability
false: adaptive immunity
43
how does the innate immune system identify foreign antigen and what's an example?
pattern recognition receptors ex. mannan binding lectin toll-like receptors
44
what do pattern recognition receptors identify antigen?
innate cells that recognize conserved microbial structures
45
how do toll-like receptors identify antigen?
innate cells that recognize variety of microbial components based on the receptor involved
46
true or false: the magnitude and duration of the innate immune response dictates whether the adaptive immune system is activated, strongerand longer the duration the greater likelihood of adaptive immune activation
true
47
what are the cells of the adaptive immune system that requires recognition of their specific epitopes?
T and B cells
48
where do APCs present processed antigen simultaneously to T and B cells if innate immunity is deemed unable to clear infection and what is the goal?
lymph nodes goal = clonal expansion-excite multiple T cells and B cells for activation and proliferation (The more clones that are activated the greater the adaptive immune response)
49
what is the central origin of innate and adaptive immunity?
hematopoietic compartment
50
where does the hematopoietic compartment develop in mammals?
during development. in fetal yolk sac then migrates to fetal liver and at birth transitions into bone marrow
51
what type of cells is the hematopoietic compartment comprised of?
stem (pluri and multipotent)
52
where does further differentiation and maturation takes place for cells of the adaptive immune system?
primary lymphoid organs
53
true or false: the primary lymphoid organs are involved in mounting an immune response to foreign invaders
false
54
what is the primary lymphoid organ for T cells?
thymus gland
55
Progenitor cells from the bone marrow migrate to the _______________ a lymphoepithelial organ
bi-lobed thymus
56
as the progenitor cells enter the thymus, what are they called?
thymocytes
57
what is the percentage of T cells that survive to exit the maturation process?
5-10%
58
what was the primary organ for B cell maturation in birds?
bursa of fabricius
59
in mammals, what is the primary lymphoid organ for B cell development?
bone marrow
60
where do the mature T and B cells migrate to after exiting the primary lymphoid organ?
secondary lymphoid organ
61
what are secondary lymphoid organs?
spleen lymph nodes lymphoid clusters bronchus associated lymphoid tissue (BALT) mucosa associated lymphoid tissue (MALT) gut associated lymphoid tissue (GALT)
62
what is the purpose for secondary lymphoid organs?
- can store large numbers of naïve and memory T and B cells for efficient trapping and presentation of foreign antigen - clonal proliferation: facilitate rapid proliferation of cones
63
what is the largest secondary lymphoid tissues?
speen
64
what is the spleen characterized by?
clusters of RBCs called red pulp and clusters of lymphoid cells called white pulp
65
where is the white pulp of the spleen located near?
germinal centers (small bvs as clusters)
66
true or false: approximately 50% of the lymphocytes are B cells and 30-40% are T cells in the spleen
true
67
where are lymph nodes found?
at all major tissue junctions
68
what is the purpose of lymph nodes?
trapping and presenting antigen to the circulating lymphocytes via the lymphatics and blood stream
69
describe the process of how T cell or B cell will encounter an APC presenting a specific antigen epitope that it can recognize
the lymphocytes circulate through the lymphatics to the thoracic duct, vena cava and blood stream and interact with APCs during their passage through the secondary lymphoid organs and tissues.
70
what is the cellular origin of granulocytes?
hematopoietic precursor cells (then they derive from myeloid precursors or pluripotent stem cell)
71
what is a Langerhan cell?
type of dendritic cell in the skin that can recognize and phagocytize pathogens, they have an incredible ability to present antigens to T cells
72
What is the difference between endocytosis and phagocytosis?
endocytosis: engulfs macro particles phagocytosis: engulfs individual cells
73
What are examples of tissue macrophages?
- kupffer cells - alveolar macrophages - splenic macrophages - peritoneal macrophages - microglial macrophages
74
What causes acute inflammation?
injury that will cause soluble mediators like cytokines, acute phase proteins, and chemokines to promote the migration of neutrophils and macrophages to the area of inflammation
75
How do innate cells recognize foreign microbial organisms?
pattern recognition: pathogen associated-molecular patterns (PAMPs) detected by germline-encoded pattern recognition receptors (PRR)