Innate Immunity Flashcards
Receptors for innate immunity are located here
Plasma membrane, endosomal membrane, cytosol
Receptors for adaptive immunity are located here
Only in plasma membrane
Distribution of receptors involved in innate immunity
Nonclonal: identical receptors on all cells that express the receptors
Distribution of receptors involved in adaptive immunity
Clonal: clones of lymphocytes with distinct specificities express different receptors
Genes encoding innate immune receptors are encoded here
Germline encoded; in all cells
Genes encoding adaptive immune receptors are encoded here
Formed by somatic recombination of gene segments only in B and T cells
Host cell-derived glycoproteins that coat pathogens and inhibit adherence
Mucin
Enzyme that degrades peptidoglycan (bacterial cell wall component)
Lysozyme
Cationic peptides (+ charge due to Arginine) that damage negatively-charged membranes - disrupt membrane integrity (bacterial, viral, and fungal)
Contain 3 intra-chain disulfide bonds
Amphipathic
Formed as inactive precursors by gut Paneth cells
Alpha and beta defensins
Specialized epithelial cells in the small intestine that secrete antimicrobial proteins such as defensins
Paneth cells
Macrophages develop from these cells
Monocytes
Monocytes can further differentiate into these cells
Macrophages
4 categories of white blood cells
Granulocytes
Mononuclear phagocytes
Dendritic cells
Lymphocytes
Most abundant cell in the innate immune response
Neutrophils
Phagocytes that are short lived, have a multi-lobed nucleus, and are most abundant cell in the innate response
Neutrophils
Type of macrophages in the brain
Microglial cells
Type of macrophages in the liver
Kuppfer cells
Branched cells involved in adaptive immunity that function as scouts in tissues
Engulf material in tissue and bring it to cells of adaptive immunity
Dendritic cells
Does this describe macrophages or neutrophils:
Rapidly induced ROS by assembly of phagocyte oxidase (respiratory burst)
Neutrophils
Does this describe macrophages or neutrophils:
Less prominent ROS response
Macrophages
Does this describe macrophages or neutrophils:
Low levels or none of nitric oxide
Neutrophils
Does this describe macrophages or neutrophils:
Nitric oxide induced following transcriptional activation of iNOS
Macrophages
Does this describe macrophages or neutrophils:
Degranulation is a major response and is induced by cytoskeletal rearrangement
Neutrophils
Does this describe macrophages or neutrophils:
Degranulation is not prominent
Macrophages
Does this describe macrophages or neutrophils:
Low levels of cytokine production per cell
Neutrophils
Does this describe macrophages or neutrophils:
Cytokine production is major functional activity; large amounts per cell; requires transcriptional activation of cytokine gene
Macrophages
When first line barrier of innate immunity are breached, the pathogen is recognized by these 2 systems
Tissue-resident macrophages and Complement
Type of macrophages in bone
Osteoclasts
Free plasma protein that is part of the collagenous lectin (collectin) family
Binds carbohydrate molecules expressed by pathogens
Mannose-binding lectin
Mannose-binding lectin binds this type of molecule expressed by pathogens
Carbohydrate
Any group of proteins that are not antibodies and do not originate in an immune system but bind specifically to carbohydrate-containing receptors on cell surfaces
Lectin
Lectins specifically bind to receptors which contain this
Carbohydrate
C-type (calcium dependent) lectin that binds sugar residues on pathogens
On the cell surface
Macrophage mannose receptor
Pathogen recognition receptors that recognize anionic polymers and acetylated low-density lipoproteins
Scavenger receptors
Type of receptors that recognize PAMPs
Toll-like receptors (TLRs)
Intracellular receptors that are similar to TLRs and recognize PAMPs
Nucleotide-binding oligomerization domain (NOD) proteins
2 main effects of triggering receptors on macrophages
Phagocytosis (via mannose receptor)
Cytokine production (via TLR)
Binding to this receptor on macrophages results in phagocytosis
Mannose receptor
Binding to this receptor on macrophages results in cytokine production
TLR
2 phagocytes that are present in healthy tissue
Macrophages and dendritic cells
Phagocytes that are recruited to site of infection when needed
Neutrophils
Competitor protein that is a phagocyte bactericidal agent that binds Fe
Lactoferrin
Respiratory burst is initiated in this
Endocyte vacuole (have lower pH0)
Enzyme that produces the superoxide anion O2- during respiratory burst
NADPH oxidase
Enzyme that converts superoxide anion O2- to H2O2 hydrogen peroxide
Superoxide dismutase
Enzyme that converts H2O2 to water and oxygen during the respiratory burst, which increases the pH and allows antimicrobial peptides (defensins) and proteins (lysozyme) to become activated
Catalase
NADPH oxidase produces this during respiratory burst
Superoxide anion O2-
Superoxide dismutase does this reaction during respiratory burst
Converts superoxide anion O2- to hydrogen peroxide H2O2
Cells that primarily perform the respiratory burst
Phagocytes (macrophages, neutrophils)
Are TLRs expressed extracellularly or intracellulary?
Can be both
Intracellular TLRs typically recognize nucleic acids (i.e. viral infection)
Lipopolysaccharide (found in gram-negative bacteria) is recognized by this receptor
TLR4
3 additional factors that aid in the recognition of LPS by TLR4
LPS-binding protein (LBP), MD2, and CD14
TLR4 recognizes this
Lipopolysaccharide (found in gram negative bacteria)
Production of this type of protein is crucial for control of viral replication during infection
Interferons
Redundancy of cytokines refers to this
Multiple cytokines perform similar functions
Pleiotropism of cytokines refers to this
A single cytokine can perform multiple functions
Class of cytokines important in chemotaxis
Chemokines
Class of cytokines important in multiplication and differentiation of leukocytes
Colony stimulating factors
Class of cytokines important in control of viral infections and inflammatory response
Interferons
Class of cytokines produced by leukocytes that have a role in both innate and adaptive immunity
Interleukins
Class of cytokines that kill tumor cells and initiate inflammation
Tumor necrosis factor
Cytokines made by the host that increase body temperature
Endogenous pyrogen
5 inflammatory cytokines secreted by resident macrophages at the site of infection
IL-1B, TNF-a, IL-6, CXCL8, IL-12
Inflammatory cytokines that induce blood vessels to become more permeable, enabling effector cells and fluid containing soluble effector molecules to enter the infected tissue
IL-1B and TNF-a
Inflammatory cytokine that induces fat and muscle cells to metabolize, make heat and raise the temperature in the infected tissue
IL-6
Inflammatory cytokine that recruits neutrophils from the blood and guides them to the infected tissue
CXCL8
Inflammatory cytokine that recruits and activates NK cells that in turn secrete cytokines that strengthen the macrophages response to infection
IL-12
Elevated IL-6 induces the production of these 2 acute-phase proteins
Leads to the activation of complement and Opsonization
C-reactive protein and Mannose binding lectin
C-reactive protein and Mannose binding lectin are induced by elevated levels of this
IL-6
Function of IL-1B and TNF-alpha
Inflammatory cytokines that induce blood vessels to become more permeable
Function of CXCL8
Recruits neutrophils
Function of IL-12
Inflammatory cytokine that recruits and activates NK cells
3 cytokines involved in neutrophil mobilization
IL-1, IL-6, TNF-a
Acute-phase protein that acts as an opsonin by binding to phosphocholine of pathogens
Induced by elevated IL-6
Triggers the classical pathway of complement in the absence of antibody
Member of the pentraxin family
C-reactive protein
C-reactive protein binds to this
Phosphocholine component of LPS in bacterial and fungal cell walls
Mannose-binding lectin is a part of this protein family
Collectin family
Family of cell adhesion molecules that bind carbohydrates and initiate leukocyte-endothelial interaction
Selectins
Cell surface proteins that bind to cell-adhesion molecules and the extracellular matrix
Integrins
Cell adhesion molecules that are ligands for integrins and bind tightly
ICAMs
ICAMs are ligands for these
Integrins
Large reserves of neutrophils are stored here
Bone marrow