Inflammation - Immunology - Cells & Tissues; Innate Immunity Flashcards
How many lines of defense does the immune system have?
Which are innate?
Which are adaptive?
3;
the first two are innate,
the third (and final) is adaptive
Indicate whether each of the following cell types is part of the innate or adaptive immune system:
B cells
Macrophages
PMNs
T cells
NK cells
B cells - Adaptive
Macrophages - Innate
PMNs - Innate
T cells - Adaptive
NK cells - Innate
Indicate whether each of the following substances is part of the innate or adaptive immune system:
Complement
Antibodies
Complement - Innate
Antibodies - Adaptive
What cell type is the main adaptive component of humoral immunity?
What cell type is the main adaptive component of cell-mediated immunity?
B cells;
T cells
Humoral immunity mainly fights infections in the _____________ space.
Cell-mediated immunity mainly fights infections in the _____________ space.
Humoral immunity mainly fights infections in the extracellular space.
Cell-mediated immunity mainly fights infections in the intracellular space.
________ immunity mainly fights infections in the intracellular space.
________ immunity mainly fights infections in the extracellular space.
Cell-mediated immunity mainly fights infections in the intracellular space.
Humoral immunity mainly fights infections in the extracellular space.
What is the first line of immune defense?
What are some examples?
External barriers (mechanical, chemical, microbiological);
skin, mucous membranes, lysozymes, low pH, respiratory cilia, microbiome
The first line of immune defense is __________ (structure type) and __________ (innate or adaptive).
External barriers;
innate
The second line of immune defense is __________ (structure type) and __________ (innate or adaptive).
Cellular;
innate
The third line of immune defense is __________ (structure type) and __________ (innate or adaptive).
Cellular;
adaptive
What is the main role of NK cells?
Are they cytotoxic?
Immune surveillance;
yes
What are the generic S/Sy of inflammation?
Pain,
redness,
loss of function,
swelling,
heat
What is the purpose of the inflammation response (ex.: reacting to a breach in the skin)?
To increase the ability of leukocytes to enter the infected/damaged extracellular area
What are the major cells of the innate immune system?
NK cells,
monocytes/macrophages,
neutrophils, basophils/mast cells, eosinophils
What are the major cells of the adaptive immune system?
B cells and T cells
How long does an initial adaptive immune response typically take?
How long does a secondary adaptive immune response typically take (i.e. after immunological memory is developed)?
~1 week;
~2 days
How long does an innate immune response typically take to begin responding to an infection?
0 - 4 hours
True/False.
B cells recognize processed antigens.
AND
T cells recognize ‘native,’ unprocessed antigens.
False.
B cells recognize ‘native,’ unprocessed antigens.
AND
T cells recognize processed antigens.
What structural complex type is used to present antigens to T cells?
MHC complexes
Upon encountering the pre-sensitized antigen, memory B cells undergo ________ selection/proliferation/expansion.
Clonal
What is the main function of germinal centers found in lymphatic tissue?
B cell activation
What diverse functions do antibodies play?
Opsonization, neutralization, complement activation
B cells recognize _________ antigens from infections in the extracellular space.
T cells recognize _________ antigens from infections in the intracellular space.
Unprocessed (native);
processed (chopped up)
B cells recognize unprocessed (native) antigens from infections in the _________ space.
T cells recognize processed (fragmented) antigens from infections in the _________ space.
Extracellular;
intracellular
True/False.
Both B cells and T cells respond to pre-sensitized antigenic stimuli via clonal selection/proliferation.
True.
The main role of TH (CD4+) cells is ___________ production.
Interleukin (cytokine)
The main role of TC cells is ___________.
Cytotoxicity
What is the major Type 1 cytokine of the immune response?
What is the major Type 2 cytokine of the immune response?
γ-interferon;
Interleukin-4
What is the major pro-inflammatory cytokine?
What is the major anti-inflammatory cytokine?
TNF-α;
interleukin-10
What are the major hormones controlling the thymus gland?
Thymopoeitin,
thymosin,
thymulin
Where do T cells get their T cell receptors (TCRs)?
The thymus
What cluster of differentiation molecule do T cells express with their CD8+ or CD4+ T cell receptors (TCRs)?
CD3
The presence of what membrane receptors would allow you to identify a cell as a T cell?
TCR, CD3
(and either CD4+ or CD8+)
95% of T cells have ___ T cell receptors (TCRs).
5% of T cells have ___ T cell receptors (TCRs).
αβ;
γδ
What happens to each T cell in the thymic cortex during activation?
What happens to each T cell in the thymic medulla during activation?
Gaining of both CD4 and CD8
(CD4+, CD8+);
loss of either CD4 or CD8
(CD4+, CD8-, CD3 [OR] CD4-, CD8+, CD3)
Primary lymphatic tissues are the site of antigen-__________ (dependent/independent) T cell differentiation.
Secondary lymphatic tissues are the site of antigen-__________ (dependent/independent) T cell differentiation.
Dependent;
independent
True/False.
Of the three layers of immune defense (barrier innate immunity, cellular innate immunity, adaptive immunity), the second (cellular innate immunity) eliminates most threats.
False.
The first line (barrier innate immunity) is actually very effective.
What is the main threat a patient with severe burns faces?
Infection
(external barrier / first line of defense removed)
Lymphocytes mainly travel through which vessels of the body?
Arteries –> capillaries (HEVs) –> lymphatics
How quickly can a single T cell pass through (and monitor) every lymph node in the body?
24 hours
T cells are found in what part of a lymph node?
plasma cells are found in what part of a lymph node?
B cells are found in what part of a lymph node?
Paracortex;
medulla;
cortex
_______ cells of the lymph node are mainly found in the medulla.
_______ cells of the lymph node are mainly found in the cortex.
_______ cells of the lymph node are mainly found in the paracortex.
Plasma;
B;
T
What types of cell provide a lot of the supportive features of a lymph node?
Macrophages (hematogenous cells),
follicular dendritic cells (stromal cells)
True/False.
The follicular dendritic cells of the lymph node provide a supportive role and are derived hematogenously from macrophages.
False.
The follicular dendritic cells of the lymph node provide a supportive role and are derived from stroma (e.g. fibroblasts).
What are the three central portions of a lymphatic germinal center?
What is the one outer portion of a lymphatic germinal center?
Dark zone –> basal light zone –> apical light zone;
the mantle zone
What occurs in lymphatic germinal centers?
B cell activation;
initial antibody production
In what particular structure of the lymph node are B cells able to switch from IgM to IgG production?
Germinal centers
What relatively large organ is full of lymphatic germinal centers?
The spleen (splenic white pulp)
Describe the basic structure of a sample of splenic white pulp.
Most infections enter through what portion of the body?
Mucosal tissues
What are the two main types of gut-associated lymphatic tissue (note: one is a specific tissue type and the other is just a layer of the gut.)?
Gut lymphocytes (in the lamina propria)
Peyer’s patches (terminal ileum)
What type of cell is a specialized APC found in the gut?
M cells
You note a cell in the lab that has a CD3 protein on its surface. What type of cell is it?
You note a cell in the lab that has a CD20 protein on its surface. What type of cell is it?
T cell;
B cell
What lymphatic tissue is present in the pulmonary bronchi?
Bronchus-associated lymphatic tissue
True/False.
In most mucosa-associated lymphatic tissue (MALT, NALT, GALT, BALT, etc.), there are more B cells than T cells.
False.
In most mucosa-associated lymphatic tissue (MALT, NALT, GALT, BALT, etc.), there are approximately even numbers* of B cells *and T cells.
In what mucosa-associated lymphatic tissue type is there an uneven amount of B cells vs. T cells?
Of which is there more?
Peyer’s patches;
B cells > T cells
Why are Peyer’s patches predominated by B cells (B > T)?
Massive IgA production
True/False.
The adaptive immune system will give better and better subsequent immune responses if facing a repeated threat.
True.
What are the two lines of defense made up by innate immunity?
- External barriers (e.g. skin, cilia, low pH, lysozymes, etc.)
- Initial cellular response (e.g. neutrophils, macrophages, NK cells etc.)
What cell type(s) of the innate immune system perform(s) immune surveillance?
Natural killer cells
What are some other colloquial names for a neutrophil?
Polymorphonuclear cells,
PMNs,
polys
List the leukocytes found in the blood in descending order of quantity.
Neutrophils >
Lymphocytes >
Monocytes >
Eosinophils >
Basophils
What type of cell can expel its DNA strands in a suicide attempt to bind to infectious agents?
What is this net formation termed?
Neutrophils;
netosis (the DNA strands are ‘sticky’ and can inhibit microbial movement)
Describe some of the basic potential functions of a neutrophil in the cardiovascular system once an infectious threat is identified in tissue.
What are the two basic forms of neutrophil netosis (chromatin net formation)?
Plasma membrane rupture (widespread net);
non-lytic (targeted attack)
What are the basic steps of the inflammatory process after an individual steps on a rusty nail and bacteria enter/bypass the skin?
Tissue leukocytes (e.g. mast cells) sense the infection and release cytokines;
these cytokines cause (1) vasodilation and (2) neutrophil chemotaxis
Fill in the blanks for the inflammatory response after the skin is breached and infected:
Tissue leukocytes (e.g. mast cells) sense the infection and release (1) __________;
these (1) __________ cause (2) __________ and (3) __________ chemotaxis.
Tissue leukocytes (e.g. mast cells) sense the infection and release cytokines;
these cytokines cause vasodilation and neutrophil chemotaxis.
Leukocytes can only adhere to / crawl along / extravasate from which type of blood vessel(s)?
Veins only
What type of protein binds leukocyte membrane carbohydrates and allows the leukocyte to adhere to venous walls?
Selectins
(a type of lectin)
What type of cell in the cardiovascular system displays selectins on its membrane?
Why?
Venous endothelial cells;
to allow leukocyte binding
Why don’t leukocytes extravasate from arteries?
Shear pressure is too high (rapid blood flow);
arterial thickness
What percentage of leukocytes are neutrophils?
60 - 70%
How long does it take for neutrophils to influx into an area of infection (e.g. via breached skin)?
< 1 hour
(very rapid)
True/False.
Eosinophils will be a major component of the cellular response to infection by single-cellular parasites.
False.
Eosinophils will be a major component of the cellular response to infection by multi-cellular parasites.
Neutrophils still predominate for single-cell parasites.
Cells of innate immunity operate via a system of pattern recognition receptors (PRRs) that recognize what?
Pathogen-associated molecular patterns (PAMPs)
(e.g. toll-like receptors)
A toll-like receptor is an example of receptors that sense what broader category of stimulant for the innate immune system?
Pathogen-associated molecular patterns (PAMPs)
Pattern recognition receptors (PRRs) of the innate immune system allow for recognition of pathogen-associated molecular patterns (PAMPs) of a specific _____ of pathogen.
Class
(not by individual pathogens)
(e.g. distinguishing between gram-negative and gram positive or between DNA or RNA viruses)
Where are toll-like receptors found (in regards to cellular structure)?
The membrane AND in endosomes
(for extracellular and intracellular pathogens)
What are these and why are the intracellular different from the extracellular?
Toll-like receptors;
the intracellular sense viruses,
the extracellular sense other threats
___ (a toll-like receptor) binds to LPS (lipopolysaccharide) to identify gram-negative bacteria.
TLR-4
TLR-4 (a toll-like receptor) binds to LPS (lipopolysaccharide) to identify __________________.
Gram-negative bacteria
What type of receptors bind to predetermined pathogen-associated molecular patterns (PAMPs such as ssDNA or ssRNA or lipopolysaccharide or flagellin) in order to identify specific categories of infectious agent and respond to them?
Toll-like receptors
True/False.
Cellular innate immunity is fast and nonspecific.
False.
Cellular innate immunity is fast and generic.
(recognition of pathogen-associated molecular patterns generic to pathogen class)
What type of cell in the skin is likely to recognize pathogen-associated molecular patterns via toll-like receptors?
What happens next?
Dendritic cells;
cell activation and travel to a lymph node
How do vaccine adjuvants (e.g. aluminium) increase immune response?
By indicating to the body that this substance is non-self
(sort of like a pathogen-associated molecular pattern)
Phagosome + lysosome = ?
Phagolysosome
What do lysosomes contain?
Lysosomal enzymes;
H+;
reactive nitrogen and oxygen species
What do macrophages do with endocytosed and digested infectious agents?
They exocytose the remaining pieces into lymph for the lymph nodes to filter
Describe the basics of the complement cascade.
NOTE: do not memorize image on reverse side of card.
The classical pathway of the complement cascade involves C__ - C__.
The alternative pathway of the complement cascade involves C__ - C__.
1, 9
3, 9
The complement cascade consists of the classical, alternative, and _____ pathways.
Lectin
The classical, alternative, and lectin pathways of the complement cascade all meet at what complement protein?
C3
What triggers the classical pathway of the complement system?
What triggers the alternative pathway of the complement system?
Antibody-antigen complexes;
microbial surfaces
What is the major result of complement activation on bacterial membranes?
Perforation and lysis
(membrane attack complex formation)
The lectin complement pathway is homologous to which other pathway?
The classical pathway
How are the classical and lectin pathways of the complement cascade different?
Classical — antibodies bind to microbe –> complement activated
Lectin — lectins bind to microbial sugars –> complement activated
What is the order of activation of the various complement cascade pathways?
Alternative –>
Lectin –>
Classical (antibody production takes time)
List the various complement cascade pathways (lectin, classical, alternative) from least to most effective.
Alternative –>
Lectin –>
Classical
True/False.
The classical pathway of the complement cascade is constitutively active at basal, low levels.
False.
The alternative pathway of the complement cascade is constitutively active at basal, low levels.
Which complement pathway (classical, alternative, lectin) does not require an immune complex to initiate?
The alternative
(no lectin- or antibody-binding necessary)
Which is the fastest/weakest complement pathway?
Which is the slowest/strongest?
Alternative;
classical
For what is C3a of the complement cascade responsible?
For what is C3b of the complement cascade responsible?
Leukocyte recruitment;
tags bacterium for destruction
The complement cascade is most useful against what type of infectious agent?
Bacteria
True/False.
The complement cascade is very effective against viruses.
False.
The complement cascade is very effective against bacteria.
Which complement protein binds antigen-antibody immune complexes?
What does it do next?
C1;
cleaves C4 and C2 into C4b / C2a (C3 convertase)
Can the complement C4a/C2b complex (C3 convertase) cleave more than one C3?
Yes;
it can cleave many
Which of the following complement proteins can cleave C5?
C4a/C2b complex
C3b
Both!
The formation of a membrane attack complex (MAC) is initiated by which complement protein?
What other complement proteins are involved?
C5b;
C6, C7, C8, and multiple C9
Describe the general makeup of a membrane attack complex (MAC).
Which complement proteins are involved in all the cascade pathways (lectin, alternative, classical)?
C3 - C9
Which is the most important initiating complement protein for successful complement activation?
Where is it located when it initiates activity?
C3b;
attached to the bacteria membrane
Describe the differences between the alternative, lectin, and classical pathways of the complement cascade.
NOTE: do not memorize the image on the reverse side of this card.
What is an easy mnemonic to remember the functions of C3a and C3b?
C3anaphylatoxin
(attracts / activates leukocytes)
C3bacteria
(binds bacterial surfaces)
What is the function of an anaphylatoxin?
A substance (often complement) that
(1) causes mast cell granule release
(2) attracts neutrophils / other leukocytes
True/False.
C3b is a potent chemotactic substance for neutrophils.
False.
C3a is a potent chemotactic substance for neutrophils.
What main issue will a C7 (complement) deficiency cause?
Susceptibility to certain bacterial infections
(decreased membrane attack complex formation)
Which is worse, a C3 or a C7 complement deficiency?
C3
(earlier in complement cascade — less leukocyte chemotaxis, etc.)
What are some of the functions of complement?
Lysis;
opsonization;
inflammatory activation;
clearance of immune complexes
What is the major function shared by complement C3a, C4a, and C5a?
Neutrophil (and other leukocyte) chemotaxis
(anaphylotoxins)
If found on a bacterium’s E-face, which of the following scenarios will have the highest rate of phagocytosis by leukocytes?
Complement - ; - antibodies
Complement - ; + antibodies
Complement + ; - antibodies
Complement + ; + antibodies
Complement + ; + antibodies
(synergystic response)
True/False.
A vaccinated / preexposed individual can activate complement faster and more strongly than an individual who has not been exposed to a particular antigen.
True.
(Faster classical pathway because antibody production can begin immediately upon encountering the antigen)
Interferons, complement, and natural killer cells are all part of what broad type of immunity?
Innate
Interferons mainly convey reistance against ________ to adjacent, uninfected cells.
viruses
__________ mainly convey viral reistance to adjacent, uninfected cells.
Interferons
True/False.
Natural killer cells cannot directly lyse self cells. They can only activate TC cells to lyse self cells.
False.
NK cells directly target/kill malignant cells and virally infected cells.
What types of cell do natural killer cells target?
Malignant cells;
virally infected cells
What type of receptor do NK cells use to recognize antibodies on virally infected self cells?
FC receptors
How do natural killer cells identify cells which are infected or malignant?
- Antibody presence on infected cell or malignant cell surface
- Lack of MHC 1 on infected cell or malignant cell surface
Viruses and tumors down-regulate the cell’s MHC 1 receptors to escape from what?
Which cell senses this change and targets the infected or malignant cells?
TC cells;
natural killer cells
What cell senses the presence of MHC 1?
What cell senses the absence of MHC 1?
TC cells;
natural killer cells
A virally infected cell will present what on its MHC1 receptors?
So, what does the virus do?
Viral segments;
down-regulates MHC1
What two types of cell are especially likely to down-regulate cellular MHC1 in order to hide from cytotoxic T cells?
Virally infected cells;
malignant cells
What are the two antibody-independent stimuli for natural killer cell lysing of a self cell?
Large increase in stimulatory ligand;
loss of MHC1 (inhibitory ligand)
Interferon-α and interferon-β tell cells to do what?
Not allow viral growth
Describe the general speed at which anti-viral components of the immune system come into play.
What are the type 1 interferons?
What releases them and what do they do?
IFN-α, IFN-β;
virally infected cells –> strongly anti-viral –> increase expression of MHC1
What is the type 2 interferon?
What releases them and what do they do?
IFN-γ;
leukocytes –> strongly boosts adaptive immunity –> increases expression of MHC1 and MHC2
Interferon-α is a type __ interferon and is _________ (strongly/weakly) anti-viral.
Interferon-γ is a type __ interferon and is _________ (strongly/weakly) anti-viral.
Interferon-β is a type __ interferon and is _________ (strongly/weakly) anti-viral.
1, strongly;
2, weakly;
1, strongly
Interferon-β increases expression of what on self cell surfaces?
Interferon-γ increases expression of what on self cell surfaces?
Interferon-α increases expression of what on self cell surfaces?
MHC1;
MHC1, MHC2;
MHC1
Which interferon(s) strongly enhance(s) adaptive immunity?
Which interferon(s) strongly enhance(s) anti-viral immunity?
Interferon-γ;
Interferon-α, interferon-β
True/False.
Virally infected cells release interferons which cause an increase in inhibitory signals to decrease natural killer cell activity.
False.
Virally infected cells release interferons which cause an increase in stimulatory signals to increase natural killer cell activity.
What type(s) of interferon cause(s) increased cellular MHC1 expression?
What type(s) of interferon cause(s) increased cellular MHC2 expression?
Interferon-α, interferon-β, interferon-γ;
interferon-γ
