Part 1 Flashcards
1
Q
what is the first line of defense
A
innate immune system: skin and mucous membranes
2
Q
what is the innate immune system
A
the defenses you are born with
3
Q
what is the innate immune system made up of
A
Surface barriers:
Skin
Mucous membranes
Internal defenses:
Phagocytes
Fever
NK cells
Antimicrobial proteins
Inflammation
4
Q
what is the second line of defense
A
Internal defenses:
Phagocytes
Fever
NK cells
Antimicrobial proteins
Inflammation
5
Q
what is the third line of defense
A
adaptive immunity
6
Q
what is adaptive immunity
A
immunity that is built up over time
7
Q
what are the parts of the adaptive immunity
A
lymphocytes (B and T), antibodies, antigen presenting cells (macrophages and dendritic cells)
8
Q
what are the roles of the third line
A
Recognizes specific foreign substances
Acts to immobilize, neutralize, or destroy foreign substances
Amplifies inflammatory response and activates complement.
9
Q
what is humoral immunity
A
the process of adaptive immunity manifested by the production of antibodies by B lymphocytes. It develops in bone marrow. B cells may be triggered to proliferate into plasma cells. Plasma cells produce antibodies.
10
Q
what do B cells do
A
protect you from infection by making proteins called antibodies.
11
Q
what are B cells
A
B-cells are a type of white blood cell called lymphocytes. When your immune system detects antigens — markers that indicate a threat like a bacteria or virus has entered your body — your B-cells produce antibodies to fight the invader.
12
Q
what are T cells
A
a type of white blood cell called lymphocytes.
Cytotoxic T-cells destroy infected cells. Helper T-cells send signals that direct other immune cells to fight infection.
wipe out infected or cancerous cells. They also direct the immune response by helping B lymphocytes to eliminate invading pathogens.
13
Q
do plants and bacteria have immune systems
A
yes
14
Q
what is the plant immune system made up of
A
The cuticle (barrier).
Phytoalexins: low molecular weight antimicrobial compounds that are produced by plants as a response to biotic and abiotic stresses. As such they take part in an intricate defense system which enables plants to control invading microorganisms.
15
Q
what is the bacteria immune system made up of
A
Endonucleases (Restriction Enzymes): recognizes and cleaves foreign DNA on the defined recognition sites.
Chopped up virus DNA is later re-inserted into the bacterial genome so the bacteria can remember the virus.
16
Q
what are the three categories of the immune system anatomy
A
lymphatic vessels, lymphatic organs, and lymph fluid
17
Q
what do the lymphatic vessels do
A
regulate fluid homeostasis, assist in immune surveillance, and transport dietary lipids.
Anastomosis: coming together after being branched off.
18
Q
what are the lymphatic organs
A
Lymph nodes
Spleen
Appendix
Peyer’s patches (tissue)
Thymus
Bone marrow
19
Q
what is lymph
A
the fluid that flows through the lymphatic system
20
Q
what is the function of lymph
A
carries the waste products and destroyed bacteria back into the bloodstream. The liver or kidneys then remove these from the blood. The body passes them out with other body waste.
21
Q
what is interstitial fluid
A
plasma that is leaked out of the blood capillaries
22
Q
what is the difference between plasma and interstitial fluid
A
plasma resides in blood vessel
IF resides outside of the blood vessel
23
Q
what is IF made up of
A
containing sugars, salts, fatty acids, amino acids, coenzymes, hormones, neurotransmitters, white blood cells and cell waste-products.
24
Q
what is the hierarchy of the lymph system
A
Lymph capillaries > lymph vessels > lymph trunk > lymph ducts.
25
what do monocytes mature to
macrophages, which differentiate in tissues
26
what cells are in the second line of defense
macrophages, neutrophils, basophils, eosinophils, NKs, and ILCs 1-3
27
what antimicrobial proteins are in the second line
complement, defensins, cathelicidins, histatins, interferons (A, B, G), lysozyme, and phospholipase A2
28
do lymph capillaries have valves?
yes
29
what are afferent vessels
vessels that go into the node
30
what are efferent vessels
vessels that go out of the node
31
what is the medulla
most inner portion of LN
32
what is the cortex
outer portion of the inside of the lymph node.
Contains follicle and germinal center.
33
what is the follicle
a loosely arranged structure with an outer mantle of small T lymphocytes and agerminal center composed of B lymphocytes, follicular dendritic cells, and macrophages.
34
what is the germinal center
in the follicle, attached to paracortical zone (T cells)
producing long-lived antibodies secreting plasma cells and memory B cells (activated), which can provide protection against reinfection.
T cells outside of the germinal center continuously activate B cells.
35
what types of pulp are in the spleen
red and white
36
what does white pulp do
produces WBCs
37
what does red pulp do
produce RBCs
38
where are Peyer's patches located
intestines
39
what do Peyer's patches do
samples stomach contents for invaders
40
where is the thymus
near the heart
41
what does the thymus do
where T cells develop
Doesn’t stop growing until puberty, then atrophies as you get older.
Secretes thymosin and thymopoietin that causes T lymphocytes to become immunocompetent.
42
what are the three types of pathogens
bacteria, viruses, parasites
43
how does bacteria enter the body
through direct bodily contact, open wounds, inhalation, or ingestion.
44
what are the properties of viruses
nucleic acids enclosed in protein coats. Some are enclosed by a membrane.
Most infect hosts to replicate.
May kill the host rapidly or lie dormant.
May cause cancer.
Must enter the cell to cause harm.
45
types of parasites
protists, fungi, worms
46
properties of parasites
Damage the host by using host nutrients or secreting toxic chemicals.
47
what are extracellular pathogens
cytoplasm-based
Bacteria (some are intracellular)
Parasites.
48
what are intracellular pathogens
vesicle-based
Viruses
Some bacteria
49
what are the other 3 subcategories for pathogens
epithelial, blood, IF
50
what are the properties of the skin
Keratin
Dryness, sebum, pH (pH between 3 and 4)
Normal microbiota
S. epidermidis
51
properties of GI tract
pH of 1 to 2
Vomiting cleans out any pathogens.
52
properties of resp tract
Trachea has cilia, goblet cells, and mucus to trap invaders.
Has antibodies
53
properties of the genitourinary tract
Urination cleans out bacteria in the tract.
54
properties of the eyes
Lacrimal glands help wash eyes from bacteria.
Tears have lysozyme and antibodies.
55
properties of sweat
Sweat has lysozyme and phospholipase A2 in body secretions.
Very salty environment.
56
how does lysozyme kill
Lysozyme is an enzyme that degrades glycosidic bonds between NAG and NAM in cell walls
57
how does phospholipase A2 kill
hydrolyzes phospholipids in membranes
58
what are granulocytes
neutrophil, baso, eosino
59
what are the big three phagocytic cells
neutro, macro, and dendritic
60
what are ILCs and NKs homologs to
T cells
61
what are NKs similar to
CD8 T cells
62
what are ILCs similar to
CD4 T cells
63
what does inflammation and fever cause
Inflammation causes neutrophils, macrophages, and dendritic cells to migrate to the site of infection.
Also brings nutrients to repair damaged tissue.
Brings antimicrobial proteins
After lymph is leaked, the mix of lymph and phagocytic and dendritic cells are drained into the lymph vessel.
When these cells go to the lymph node, they are met with T and B cells)
64
what are the characteristics of inflammation
heat, redness, swelling, pain
65
what cell gives rise to all blood cells
pluripotent hematopoietic stem cells (PHSC)
66
heirarchy of T, B, and NK cells
PHSC >
common lymphoid progenitor>
B/T/NK cell>
B/T/NK cell moves to LN>
B/T/NK cell activated
67
heirarchy of dendritic cell
PHSC >
common myeloid progenitor >
immature DC >
DC moves to tissues >
DC matures in LN
68
heirarchy of granulocytes
PHSC >
common myeloid progenitor >
gran/macro progenitor (blood) >
neutro/baso/eosino
69
heirarchy of mast and macros
PHSC >
common myeloid progenitor >
monocyte or mast cell precursor (blood) >
mature mast or macro (tissues)
70
properties of macrophages
3-8% of cells
Eats everything, including cancer cells.
Microglial: CNS
Kupffer cells (liver)
Alveoli (lungs)
71
properties of neutros
60-70%
Eat bacteria.
Die soon after they consume bacteria
What pus is made of
MO clean out dead neutrophils
72
properties of basophils
0.5%-1%
Promotion of allergic responses and augmentation of anti-parasitic immunity.
73
percentage of eosinos cells
2-4%
74
what are the most important phagocytic cells
macros and neutros
75
which granulos relate most to parasitic
baso and eosino
76
how do baso and eosino kill parasites
The granules in these cells contain various cytotoxic granule proteins and reactive oxygen species that can be released to kill parasites (death by a thousand cuts)
77
what do mast cells release
granules containing histamine and active agents
78
what are pattern recognition receptors
a class of receptors that can directly recognize the specific molecular structures on the surface of pathogens, apoptotic host cells, and damaged senescent cells.
79
where are PRRs found
on the surface of macrophages, neutrophils, and dendritic cells
Also in GI and Resp lining cells
80
what do PRRs recognize
recognize Pathogen-associated molecular pattern molecules (PAMPs)
81
what are PAMPs
a diverse set of microbial molecules that share a number of different general “patterns,” or structures, that alert immune cells to destroy intruding pathogens.
82
where are PAMPs located on the antigen
on the surface
83
what microorganisms bear PAMPs
bacteria, viruses, fungi
84
What are Toll-Like Receptors (TLRs)
recognize specific classes of
infecting microbes
85
what do TLRs do if they detect a pathogen (activated)
trigger the release of cytokines that support inflammation.
86
what PAMP is on Gram negative bacteria
LPS
87
what PAMP is on Gram positive bacteria
teichoic acids
88
what receptor binds to recognize fungi
mannose receptor
89
what TLRs are always bound together
TLR 1 and 2
90
what does TLR 4 do
leads to the production of pro-inflammatory cytokines via the MyD88 dependent or independent pathway.
91
what do scavenger receptors do
recognize anionic charges
92
what is the first step of when bacteria bind to receptors
they are engulfed and degraded by lysosomes.
93
what is the second step of when bacteria bind to receptors
Bacteria components are bound to receptors that trigger transcription of inflammatory cytokines. Cytokines are released into bloodstream.
94
what happens when cytokines are released into bloodstream
blood vessels swell due to relaxed smooth muscle in the vessel. This loosens the junctions of vessel cells. Interstitial fluid leaks more into the cells.
95
what is also released when macrophages are triggered by bacteria
chemokines
96
what do chemokines do
induce cell migration
97
what is extravasation
white blood cells travel through blood cell walls and tissues to locate and manage injuries and infections.
98
what is the first step of extravasation
rolling adhesion
99
what is the function of rolling adhesion
selectins are on epithelial/leukocyte/platelet cells, which bind loosely to neutrophils, which slows down cells
100
second step of extravasation
Tight binding: ICAM (intracellular adhesion molecule) tightly bind to neutrophil
101
third step of extravasation
Diapedesis: move WBC through blood capillary cell walls
102
fourth step of extravasation
Migration: neutrophil fully moves from capillary to tissue
103
what does plasma contain
sugars, salts, buffers, wastes, oxygen, CO2, proteins (albumin 60%) (globular alpha, beta, gamma (antibodies) 36%) (fibrinogen 4%).
104
what is the complement system
made up of a large number of distinct plasma proteins that react with one another to opsonize pathogens and induce a series of inflammatory responses that help to fight infection.
105
how many proteins are in the complement system
about 30
106
what do the proteins in the complement system react with
PAMPs
107
what do the majority of the proteins in the complement systems do
A number of complement proteins are proteases that are themselves activated by proteolytic cleavage.
108
how is the classical complement system activated
by antibody-antigen binding on bacterial surfaces
109
classical complement pathway
antigen-antibody contact cause conformational changes >
C1 >
C2 and C4 > cleavage of both components
C2a and C4b converge >
C3 formed > cleaved
C3b and C3a
110
what does C3b result in (all)
opsonization and cytolysis
111
what does C3a result in (all)
inflammation
112
what is opsonization
an immune process which uses opsonins to tag foreign pathogens for elimination by phagocytes.
113
how is alternative complement system activated
triggered by contact with various proteins, lipids and carbohydrate structures on microorganisms and other foreign surfaces
114
alternative complement pathway
B, D, and P factors bind to microbe's lipid-carb complexes >
C3 > cleaved
C3b and C3a
115
how is lectin complement system activated
lectin binds to the microbe's surface carbohydrate, which contains mannose
116
what is the lectin complement system pathway
lectin binds to microbe's surface carb (mannose) >
C2 and C4 > cleaved
C2a and C4b converge >
C3 >
C3b and C3a
117
what are interferons
a group of signaling proteins made and released by host cells in response to the presence of viruses, bacteria, parasites or tumor cells. .
118
what is the function of interfeons
allow for communication between cells to trigger the protective defenses of the immune system that eradicate pathogens or tumors.
119
what happens when interferons are transcripted
interferons are released from the cell, which bind to neighboring cells. Neighboring cells transcribe and release antiviral peptides (AVPs) that degrade viral mRNA
120
what do IFNs cause
Inflammation
Cell replication/activation
Production of AVP
Production of other cytokines
chemotaxis
121
what do alpha and beta IFNs do
Cause cells to produce
antiviral proteins that
inhibit viral replication
122
what do gamma IFNs do
Causes
neutrophils and
macrophages
to phagocytize bacteria.
123
what does virulent mean
ability of an organism to infect the host and cause a disease.
124
how can pathogen virulence vary
If the pathogen:
Has a capsule that helps evade the immune system.
Has toxins that are released and kill cells
Enzymes that are secreted that evade immune system
The number of pathogens that dictates whether or not you get sick.
125
how does number of pathogens determine virulence
Sufficient numbers of pathogen overwhelm second line of defense (phagocytic cells)
126
what happens when a pathogen gets degraded
a vesicle with a receptor binds to the degraded pathogen and is later expressed on the cell surface of the phagocytic cell. MHC II is what is expressed on the cell surface.
127
what is an antigen
a fragment of the pathogen that triggers an immune response.
128
what happens after an antigen is expressed on MHC II
Antigen–MHC complexes are recognized on the cell surface by the TCR of CD4+ T cells
129
what cell only recognizes proteins
T cells
130
what are antigen presenting cells
phagocytic cells
131
what is TH1
T Helper cell 1
132
what do TH1s produce
interferon-gamma, interleukin (IL)-2, and tumour necrosis factor (TNF)-beta
133
what do TH1 products do
activate macrophages, NKs, and CD8s
134
what do TH1s determine
whether pathogen is viral or bacterial
135
what do TH1s mainly fight
any intracellular pathogen
136
what do TH2s mainly respond to
pathogens in mucus or parasites
137
what do TH17s mainly respond to
anything extracellular
138
what do TH17s activate
neutrophils
139
what is the purpose of THs
they are T regulatory cells
140
what do TH2 cells activate
baso, eosino, Mast
141
when are NKs and CD8s activated
during a virus or when a cell is stressed (cancer)
142
how do NKs destroy cells
by releasing of lytic granules or by inducing death receptor-mediated apoptosis
143
how do CD8s destroy
by releasing granzymes and perforin (causes holes in membrane)
144
what do dendritic cells activate
CD4, CD8, NKs, B cells.
DCs do not fully activate CD8/NK
145
what are the regions of antibodies
variable and constant region
146
what is the variable region
top part of the Y
unique and created at random
147
what is the function of the variable region
The primary role of the antibody variable region is to bind to the target antigen.
148
what is the constant region
bottom part of the Y
always is the same
149
what is the function of the constant region
determines the mechanism used to destroy antigen
150
where do T cells come from
bone marrow to thymus (mature)
151
where do B cells come from
red bone marrow
152
how are T cells selected in the thymus
Thymic cells present a self-antigen to t cell receptor, and bind.
153
what is positive selection if cell fails to recognize self-MHC
apoptosis; binds too loose.
154
what is positive selection if it binds to MHC correctly
causes MHC restriction of survivors; bound at correct tightness and leave thymus.
155
what is negative selection if T cells bind to MHC and reacts vigorously with self-Ag
causes apoptosis, which causes surviving cells to become self-tolerant; too tight of binding, and might cause mounting in immune response when it doesn’t need to.
156
what is the postulates of clonal selection theory
in a preexisting group or population of lymphocytes, a particular antigen can activate only its specific counter cell, inducing that specific cell to multiply and create clones for antibody production
157
where does the removal of potentially immature lymphocytes by clonal deletion happen
thymus
158
where does differentiation happen for T cells
thymus
159
where does the pool of mature naive lymphocytes
thymus
160
what is peripheral immunocompetence
immunological tolerance developed after autoreactive T and B cells mature and enter the periphery.
161
where does the proliferation and differentiation of activated specific lymphocytes to form a clone of effector cells happen
peripheral
162
stages of antigen presenting
B cell presents antigen to T cell >
T cell sends signals >
T cell diff into TH1 or 2
163
what is the role of MHCII
to present processed antigens, which are derived primarily from exogenous sources, to CD4(+) T-lymphocytes. MHC class II molecules thereby are critical for the initiation of the antigen-specific immune response.
164
what is the role of MHCI
to display intracellular proteins to cytotoxic T cells (CTLs). However, class I MHC can also present peptides generated from exogenous proteins, in a process known as cross-presentation.
165
what do T cells recognize
proteins only
166
what is the role of BCRs
interacts with foreign antigens to mediate B cell activation and secretion of antibodies.
167
how many TCRs are there
about 100,000
168
how many TCRs need to be bound to create activation
50
169
what is clonal selection
picking the specific T cell to the antigen.
170
what is clonal expansion
army created of the specific T cell.
171
what is clonal differentiation
maturation of the naive T cell.
172
what are TH and T cells complements of
ILCs
173
what are NKs complement to
CD8 T cells
174
why is MHC I expressed
it is a way for infected cells to express to the immune system that it needs CD8 cells through expressed pathogen particles on the cell surface.
175
what do plasma cells secrete
antibodies
176
how does the antibody bind to an antigen
Antibody can bind directly to the antigen; antigen does not need to be digested first.
177
how does a antibody react to an antigen
neutralization or opsonization
178
Describe how the second and third branches of immune system are interlinked and
help/regulate each other
The innate immune system tells the adaptive immune system when it's time to help mount a defense.
The phagocyte is also known as an antigen-presenting cell because after engulfing the invading microbe, it displays pieces of protein from the microbe, called antigens, on its surface, on what is known as the major histocompatibility complex (MHC) molecule. This alerts the adaptive immune system and allows cells known as T cells to recognize an infected cell.
179
effector functions of CD4
crucial in achieving a regulated effective immune response to pathogens. Naive CD4⁺T cells are activated after interaction with antigen-MHC complex and differentiate into specific subtypes depending mainly on the cytokine
180
effector function of CD8 cells
kill virus-infected cells and produce antiviral cytokines such as interferon gamma. In this way, CD8 T lymphocytes contribute to resisting primary and secondary viral infections.
181
effector functions of antibodies
Antibodies are secreted into the blood and mucosa, where they bind to and inactivate foreign substances such as pathogens and toxins (neutralization).
Antibodies activate the complement system to destroy bacterial cells by lysis
182
what is positive in t cells
T cells in the thymus that bind moderately to MHC complexes receive survival signals, which turn T cells into mature, specific t cells.
183
what is negative selection in t cells
deletes T cells with high affinity for self-peptides via apoptosis, thus ensuring selftolerance, and is presumed to reflect strong signaling via TCR recognition of peptide–MHC complexes on APC.
184
what is positive selection in b cells
Developing B cells are positively selected when the pre-B receptor binds its ligand.
185
what is negative selection in b cells
binding to the receptor results in cell death ( self tolerance)
