Innate Immunity Flashcards
Identify common examples of pathogen infection routes.
Airway, GI tract, Reproductive tract, External surfaces, Wounds/ abrasions, Insect bites
The complement system, use of cytokines like interferons, inflammation and a fever, are examples of a _________ lines of defense of the body.
Secondary
The first line of defense against pathogens would be -?
The skin, mucous membranes, and chemicals
While non-specific and quick acting, there are only a few examples of memory production. What immunity is being referred to?
Innate immunity
If an innate immune response can be activated within the first 4 hours of initial infection, how long would an adaptive immune response take to begin?
Over 96 hours, or 4 days
What apparatus within the respiratory tract is crucial for the elimination of pathogens and preventing their entry?
The mucociliary apparatus
Which of the following is true?
A) Fatty acids and an increased proton concentration have bactericidal effects
B) Surfactant material produced by Type II pneumocytes contain opsonins
C) A washing effect is achieved by the tears and saliva, which contain crucial enzymes for pathogen degradation
D) Normal microbiota secrete inhibitory substances to inhibit the growth of pathogens
E) Two of the above
F) Three of the above
F) Three of the above (B, C, and D)
Fatty acids found in sweat only inhibit bacterial growth
What common characteristic is shared between the skin, gut, lungs, eyes, and nose?
Cells contain tight junctions limiting the movement of pathogens paracellularly
The ________ system is the most important humoral factor of innate immunity.
Complement
T/F: Associated with coagulation, thrombocytes are capable of secreting beta-lysine, which has bactericidal effects against Gram Negative bacteria.
False, against Gram Positive bacteria
________ and ______ are responsible for iron sequestering from bacterial pathogens, while _______ has capabilities to breakdown the mucopeptides of the bacterial cell wall.
Lactoferrin and Transferrin
Lysozyme
Interleukin 1 is associated with what two conditions?
Fever and the induction of acute phase proteins
What cytokines can be secreted to inhibit the growth and replication of viruses extracellularly?
None, viruses are obligate intracellular pathogens
What two cells are considered “professional” phagocytes?
Neutrophils and macrophages
What cells are identified solely by the expression of CD66 on their cells surface?
Neutrofiles
What granules are present with Neurtrophils?
Azurophilic and Secondary granules
While lysozyme can be found in both azurophilic and secondary granules, what other molecules are present within azurophilic granules?
Defensins (inhibit bact. growth), Proteolytic enzymes (degrade bact. proteins), and Myeloperoxidase (req. for bactericidal substances)
What is the purpose for myeloperoxidase?
To produce bactericidal substances like HClO^(-) (hypochlorous acid) due to the fusion of a chloride anion and hydrogen peroxide
What is the purpose of NADPH oxidase?
For the production of toxic radicals
What markers are associated for the differentiation of macrophages from other cells?
CD14, CD11b, F4/80
What signal or stimulation is needed for Macrophages to be activated for phagocytic degradation of pathogens?
SOS or Danger signals, which are produced at the area of pathogen entry, etc.
What 4 examples are given in lecture, which represent SOS signals?
N-formyl-methionine, peptides, complement system, and cytokines
What danger signal is produced by bacterium upon entry and infection within host tissues?
N-formyl-methionine, which initiates protein synthesis in bacterium
What function do SOS signals have for macrophages?
Chemotactic roles
Where are Fc receptors found, and what do they bind to?
Fc receptors are found on macrophages, and they bind to Fc binding sites of antibodies (bound to an antigen)
Within the complement system, what component is needed to bind to an antigen to later bind to a phagocyte?
C3b complement, which then binds to a receptor of the phagocyte
SRA, CD68, Lox-1 and CD36, are all examples of macrophage receptors that bind to various polyamines found on bacterial surfaces. What types of receptors are these?
Scavenger receptors
TLRs respond following the recognition of ______________________________, which stimulates macrophages to bind to antigens and secrete cytokines.
Pathogen Associated Molecular Patterns (PAMPs)
Within the innate response, following the secretion of cytokines, such as IL-1, TNF alpha, and IL-6, what will occur?
Inflammation
Following the endocytosis of a pathogen, what will occur?
The enclosed pathogen in the phagosome will then fuse with a lysosome (now called a phagolysosome), which lead to its intracellular degradation
What occurs to the degraded material following phagocytosis?
Exocytosis of degraded contents, production of MHC complexes
What cells are capable of oxidative and non-oxidative mechanisms of pathogenic degradation via phagocytosis?
Neutrophils, Monocytes, and Macrophages
In order for respiratory burst to occur, what two molecules are needed?
Glucose and Oxygen
Which of the following does not occur during respiratory burst?
A) Glucose is metabolised to form NADPH through the pentose-phosphate pathway
B) Cytochrome peroxidases activates NADPH to react with oxygen to form a superoxide anion
C) NADPH activates oxygen to produce a superoxide anion to reduce hydrogen peroxide into more oxygen
D) Superoxide anion reacts with hydrogen peroxide to form hydroxyl radicals and ions
B) Cytochrome [oxidases] activates NADPH to react with oxygen to form a superoxide anion
While a superoxide anion can react with hydrogen peroxide, what else can it react with and form?
It can react with nitric oxide to produce peroxynite (ONOO^(-)), a reactive nitrogen species
What will form if nitric oxide were not reacted with superoxide anion, and only oxidized?
The formation of reactive nitrogen species nitrogen dioxide (NO2)
______ (a cytokine) is used in the formation of iNOS, nitric oxide synthase, which will produce ________ from L-arginine.
TNF alpha
Nitric oxide
What cytokines are associated with the production of iNOS?
TNF alpha and IFN gamma
What role do cationic proteins have, and what organelle are they located in?
Located within lysosomes, they damage the bacterial cell wall
Host sentinel cells, like macrophages, dendritic cells, and mast cells, are able to sense what two types of molecules?
PAMPs and DAMPs
What is the difference between PAMPs and DAMPs?
DAMPs are endogenous molecules that are released from damaged cells, whereas PAMPs are molecules are repetitive motifs found on pathogens and not on host cells
What receptors are responsible for recognition of PAMPs and DAMPs?
PRRs or Pattern Recognition Receptors
TLRs, NLRs, RLRs, CLRs, and PRGPs, are all examples of PRRs. Which of the following are the major receptors found both intracellularly and extracellularly?
TLRs, or Toll-like receptors
While TLR3 are associated with ____________ viruses, TLR7 and TLR8 are associated with ___________ viruses.
TLR 3 = dsRNA viruses
TLR 7/8 = ssRNA viruses
What is recognized by TLR9?
Bacterial DNA and some herpesviruses
Which of the following TLRs would not be activated by the MyD88? A) TLR3 B) TLR7 C) TLR9 D) TLR12`
A) TLR3
This TLR is activated via TRIF
T/F: The result of the activation of TLRs is the synthesis of proinflammatory cytokines.
True
TLRs, NLRs, RLRs, CLRs, and PRGPs, are all examples of PRRs. Which of the following are the major receptors found only intracellularly, and sense intracellular bacteria in the cytoplasm?
NLRs, Nod-like receptors
NOD1 and NOD2 receptors are associated with the activation of what transcription factor?
NF-kB, which transcribes and translates for proinflammatory cytokines
How are NOD1 and NOD2 differentiated based on their recognition of intracellular bacteria?
NOD1 = Peptidoglycans NOD2 = Muramyl peptides
T/F: NLRs are unable to be stimulated by DAMPs.
False, they can be
Interferon regulatory factors 3 and 7 are associated with the production of what type of interferons?
Type 1 Interferons
TLRs, NLRs, RLRs, CLRs, and PRGPs, are all examples of PRRs. Which of the following are associated with viral RNA detection in the cytoplasm, and the production of antiviral and inflammatory cytokines?
RLRs, or RIG-like receptors aka Retinoic acid inducible gene-like receptors
TLRs, NLRs, RLRs, CLRs, and PRGPs, are all examples of PRRs. Which of the following are associated with fungal pathogens as they bind to their carbohydrates?
CLRs, or C-type Lectin receptors
While produced on most cell types, what two antigen presenting cells are associated with this cell receptor?
Macrophages and dendritic cells
TLRs, NLRs, RLRs, CLRs, and PRGPs, are all examples of PRRs. Which of the following are associated with detecting peptidoglycans on the surface of Gram positive and negative bacterium, as these receptors are located in granules of neutrophils?
PGRPs, or Peptidoglycan-recognition proteins
If a bacterium is detected by PGRP, this will lead to the synthesis of -?
Defensins (bactericidal functions)
In what species, will PGRPs be produce exclusively in the skin, bone marrow, and intestines?
Porcine, swine, pigs, etc.
LPS, lipoteichoic acid, and polymers of N-acetylglucosamine and N-acetylmuraminic acid, are detected by what PRRs?
PGRPs, or Peptidoglycan-recognition proteins
What is the acute phase response?
The increase or decrease of serum proteins, based on the synthesis of TNF alpha, IL-1, and IL-6, which are proinflammatory cytokines
T/F: The majority of the acute phase proteins are synthesized by the liver.
True
While the end result of the acute phase proteins leads to activating the complement system, they can also be considered -?
CRPs, or C-reactive proteins
The ligands for the CRPs are bacterial pneumococcal ____________ and ____________, which will promote phagocytosis and activating the complement system.
Polysaccharides and Phosphorylcholine
T/F: Mannose-binding lectin is an acute phase protein, which recognizes mannose on bacterial surfaces.
True
In what method do both CRPs and MBL proteins have on bacterium?
Opsonization
