Immuno: Innate Immunity Flashcards
Innate immunity is the…
First line of defense that is present at birth
Adaptive immunity is the…
Second line of defense that is acquired as a result of exposure
Time of response and memory of innate immunity:
-rapid (0-4 hours)
-no immunologic memory (1st and 2nd infection have same responses)
Time of response and memory of adaptive immunity:
-slower (>96 hours)
-immunologic memory (2nd time infected the response is faster and stronger)
Antigen specificity and lag time of innate immunity:
-NOT antigen specific (same cells have same reaction to many invaders)
-no lag time, immediate maximal response
Antigen specificity and lag tome of adaptive immunity:
-antigen specific response (unique cells activated to a single invaders)
-there is lag time between exposure and response
Anatomical and chemical barriers to innate immunity:
-mechanical factors
-chemical factors
-biological factors
Cellular components of innate immunity:
-neutrophils
-monocytes and macrophages
-NK cells
-eosinophils
Plasma proteins in innate immunity:
-cytokines
-compliment proteins
Structural defenses of the innate immune system respond to..
Nonspecific foreign substances
Mechanical barriers to prevent infection in the skin and gut:
-Epithelial cells joined by tight junctions
-longitudinal flow of air or fluid
Chemical barriers to prevent infection in the skin:
-fatty acids
-anti-microbial peptides
Chemical barriers to prevent infection in the gut:
-low pH
-antimicrobial enzymes
-antimicrobial peptides
Mechanical barrier to prevent infection in the lungs:
-epithelial cells joined by tight junctions
-movement of mucus by cilia
Mechanical barrier to prevent infection in the eyes, nose, and oral cavity:
-epithelial cells joined by tight junctions
-tears and nasal cilia
Chemical barriers tot prevent infection in lungs:
-pulmonary surfactant
-antimicrobial peptides
Chemical barrier to prevent infection in the eyes, nose and oral cavity:
-antimicrobial enzymes in tears and saliva
-antimicrobial peptides
Microbiological barriers to prevent infection in skin, gut, lungs, eyes, nose, and oral cavity:
-normal microbiota
Goblet cells
Secrete slimy and sticky mucus that trap the pathogen
Cilia
Hair-like projections that move in a wavy fashion that take the pathogen to the pharynx to spit out or swallow
Sebum
Oily substance produced by sebaceous glands that form a protective layer over the skin
Why does sebum contain unsaturated fatty acids?
To inhibit growth of certain pathogenic bacteria and fungi
Dermcidin
A sweat gland, Produces sweat
Low skin pH is caused by…
Lactic acids and fatty acids
Lysozyme:
-Enzyme that breaks down gram-positive cell walls
-found in nasal secretions, saliva, and tears
Gastric juice
-Mixture of HCl, enzymes, and mucus
-destroys many microbes and most toxins
Helicobacter pylori
Can grow in the stomach by neutralizing stomach acid and causes gastritis and ulcers
Transferrins
Iron binding proteins in blood that inhibit bacterial growth by reducing available iron
The human microbiome is the…
Aggregate of all the microbiota that reside on or within humans
Neutrophils do NOT…
Present antigens
Phagocytosis is carried out by:
-neutrophils
-macrophages
-dendritic cells
Neutrophils predominate…
Early in the infection
Macrophages and dendritic cells originate from…
Monocytes
macrophages and dendritic cells are ___________________ as they recognize _____________________`
Pattern recognition receptors (PRRs), pathogen-associated molecular patterns (PAMPs)
Pattern recognition receptors are receptors on…
Innate immune cells: macrophages, dendritic cells, and mast cells
Binding of toll-like receptors to pathogen-associated molecular patterns(PAMPs) on pathogen surface triggers:
-activation of immune cell
-cytokine and chemokine production
-induction of induced inflammatory response
LPS binds _____________________ found in plasma
LPS binding protein
What and where does LPS binding protein bind?
CD14 on macrophages which triggers the TLR4
LPS triggers
TLR-4
Bacterial peptidoglycan triggers…
TLR-2
Bacterial flagellum triggers…
TLR-5
Three key functions of monocytes and macrophages:
-phagocytosis
-cytokine production
-antigen presentation
Microglia
Macrophages in the brain
Alveolar Mphi
Macrophages in the lung
Kupffer cells
Macrophages in the liver
Resident or mesangial cells
Macrophages in the kidney
Langerhans cells
Macrophages in the epidermis
Process of phagocytosis:
-microbe adheres to phagocyte
-phagocyte forms pseudopods that engulf the particle
-phagocytic vesicle is fused w/ lysosome
-microbe is fused in visible is killed and digested leaving a residual body
-ingestible and residual material is removed via exocytosis
Opsonization
Coating pathogen with opsonin that facilitates attachment
Opsonins include…
Antibodies and compliment proteins
IL-1, TNF, and IL6 have crucial roles:
-induce the acute-phase response in the liver
-induce fever
IL1 local effects:
-activates vascular endothelium
-activates lymphocytes
-local tissue destruction
-increase access of effector cells
IL-1 systemic effects:
-fever
-production of IL-6
TNF local effects:
-activates vascular endothelium
-increases vascular permeability leading to increased IgG entry, complement, and cells to tissues
-increased fluid drainage to lymph nodes
TNF systemic effects:
-fever
-mobilization of metabolites
-shock
IL-6 local effects:
-Lymphocyte activation
-increased antibody production
IL-6 systemic effects:
-fever
-induces acute-phase protein production
IL-1, TNF, and IL-6 to the hypothalamus cause…
Increased body temperature which leads to decreased viral and bacterial replication
C reactive protein is produced by the _______ in response to…
Liver, IL-6 acting on hepatocytes
C relative protein binds _______________ on bacterial surfaces acting as a opsonin and a compliment activator
Phosphocholine
Mannose-binding lectin binds to ________________ on bacterial surfaces acting as an opsonin and as a complement activator
Carbohydrates
Neutrophil is derived from _____________ and stains _____ with wright stain
Bone marrow, pink
Neutrophil enters tissues via____________ to provide extra support to macrophages
Phagocytosis
Neutrophil exit blood stream: rolling method:
-selectin ligand on neutrophils binds E-selectin of P selection on endothelial cells
-slows down
Neutrophil blood stream exit: crawling method:
-neutrophils express integrin
-bind ICAM on endothelial cells
-STOPS
What stimulates integrin on neutrophils?
LPS: C5a
Neutrophil blood stream exit: transmigration:
-neutrophils bind PECAM-1 (found between endothelial cells)
Neutrophil blood stream exit: migration to site of inflammation:
-chemokines: C5a, IL8
What stimulates expression of P and E selectin on endothelial cells?
IL-1 and TNF
Neutrophil killing process by granules :
-bacterium phagocytized by neutrophil
-phagosome fuses with azurophilic granules and specific granules
-pH of phagosome rises, antimicrobial response is activated and bacterium is killed
-pH of phagosome decreases, fuses with lysosome allows hydrolases to degrade bacterium completely
-neutrophil dies by apoptosis and phagocytized by macrophage
Primary granules:
Acid phosphatase, myeloperoxidase
Secondary granules:
Phosphatase, collagenases, and lysozymes
Neutrophil killing process: respiratory burst (oxidative burst):
Oxygen becomes superoxide, then to myloperoxidase via superoxide dismutase
Natural killer cells have the same lineage as…
B cells and Tcells
Things natural killer cells DONT do:
-do not mature in thymus
-do not have memory
-do not require antigen present by MHC
Functions of natural killer cells
-kills human cells infected with viruses
-produces IFN-Y to activate macrophages
Natural killer cells have ______ on the surface and ________
CD16 , CD56
CD16
-binds Fc of IgG
-enhances. The activity of antibody dependent cell-mediated cytotoxicity (ADDC)
CD56
-also called NCAM (natural cell adhesion molecule)
-aids in cell binding
Antibody-dependent cell mediated cytotoxicity (ADCC) in natural killer cells:
-antibodies coat pathogen or cell
-pathogen destroyed by immune cells
-non-phagocytic process
NK cell activation is coordinated by the net signals received from ____________ and ______________ receptors
Activating and inhibiting
