Pathology Week 3: Quiz 2: Diseases of the Immune System- Innate Immunity Flashcards
Mediated by cells and proteins that are always present and react to infectious pathogens.
Innate immunity
Innate immunity provides the first line of defense in response to what?
infection
Innate immunity are involved in clearing what products from the body?
damaged cells and tissues
A major reaction of innate immunity
Inflammation
Major component of innate immunity
epithelial barriers
What do epithelial barriers do in innate immunity?
block the entry of microbes
What cells comprise the innate immune system?
- Phagocytes (neutrophils and macrophages)
- Dendritic cells
- NK cells
Express receptors that sense the presence of infectious agents that are released form dead cells.
Cells of innate immunity
What happens when pathogens have evolved to resist innate immunity and protection against these infections requires a more specialized approach?
Adaptive immune system takes over
How do the innate and adaptive immune systems differ: number of substances they can recognize?
Innate: Vast array
Adaptive: Less
How do the innate and adaptive immune systems differ: Response timing
Innate: Rapid
Adaptive: Slow
How do the innate and adaptive immune systems differ: recognition receptors
Innate: germ-line encoded, CD14, mannose and scavenger
Adaptive: initially low affinity
How do the innate and adaptive immune systems differ: Response to recognition of pathogen
Innate: increased cytokines, costimulatory molecules
Adaptive: Gene rearrangement, clonal expression
How do the innate and adaptive immune systems differ: Result of response
Innate: Phagocytosis, antimocrobial activity
Adaptive: T and B cells with receptors encoded, memory
Two lines of defense of innate immunity
- Natural barriers
2. Inflammatory response
What are considered the natural barriers involved in innate immunity?
- Intact skin/epithelial cells
- Simple chemicals
- Mucous membranes/Mucous
- Cilia
- Normal Bacterial Flora
Closely packed cells, multiple layering, continuous shedding of cells, and presence of keratin.
Intact skin as a natural barrier
Create non specific, salty, acidic environment, and antibacterial proteins
Simple chemicals as a natural barrier
GI, respiratory, urogenital tracts
Mucous membranes as a natural barrier
Block and destroy microbes by secreting antimicrobial enzymes, proteins and peptides.
Epithelial cells as a natural barrier
Traps and washes away invaders.
Mucus as a natural barrier
Moves microbes out of tract, sneezing and coughing
Cilia as a natural barrier
Second line of defense in innate immunity, involves cellular and chemical components
Inflammatory response
What are the cardinal signs of the inflammation response?
- Redness
- Heat
- Swelling
- Pain
- Loss of function
When epithelial barriers are not enough to protect what is activated ?
The inflammatory response
Infection, mechanical damage, O2 deprivation, nutrient deprivation, genetic/immune defects, chemical agents, temperature extremes, and ionizing radiation are what?
Inflammatory response triggers
Is the inflammatory response specific or non specific?
non specific
Inflammatory Response Process
- Damaged cell releases inflammatory mediators
- Nearby Mast cells release inflammatory mediators
- Vascular, cellular, and systemic (or acute phase) response
- brief capillary constriction
- blood vessel dilation
- increased vascular permeability
- leakage of fluid out of the vessel
- WBCs adhere to the inner walls of vessels
- WBCs migration through vessel walls to the site of the injury
Blood flow bringing the cells what they need to heal.
Vascular inflammatory response
Cleaning out of debris and infections and directing the healing process.
Cellular inflammatory response
The body getting all the systems to help in the inflammatory response
Systemic or acute phase inflammatory response
Activation of plasma protein systems that can kill invaders directly, and collaborate with all other aspects of inflammatory response.
Complement cascade
Makes fibrinous meshwork at injured site, traps microorganisms, forms clots.
Clotting cascade
What is the end product the clotting cascade?
Fibrin
Augments inflammation and produces bradykinin.
Kinin cascade
Causes pain, leukocyte chemotaxis and vascular permeability.
Bradykinin
REVIEW CHART WITH CELL DIFERENTIATION
REVIEW CHART WITH CELL DIFERENTIATION
Cells of Innate Immunity
- Neutrophils, Macrophage, dendritic: phagocytic
4. Mast Cells, Eosinophils, Basophils, NK: innate leukocytes
Neutrophils
- quick
- early phagocyte
- within 6-12 hours of injury
- die at site
- pus
Macrophage
- more efficient phagocyte (than neutrophils)
- second arrival in injury
- 3-7 days after injury
- activate adaptive immune system
- promote healing
- help to contain infectious agents until adaptive immunity is functional and can come to help
Natural killer cells (NK cells)
have activating receptors and inhibitory receptors
Mast Cells
- central cell in inflammation
- easily activated
- histamine, chemotactic factors cytokines (which release histamine) interleukins, leukotrienes, prostaglandins, platelet-activating factor
- chemotaxis and TNF
Eosinophils
- help regulate mediators released from mast cells
2. primary defense against parasites
Basophils
associated with allergies and asthma.
Three primary changes in acute inflammatory response
- Fever
- Leukocytosis
- Increased levels of circulating plasma proteins
What is occurring when Cytokines (IL-1) are released from neutrophils and macrophages “endogenous pyrogens” and Pathogen-produced pyrogens are exogenous pyrogens?
Fever in an acute inflammatory response
What is occurring when primarily neutrophils increase possibly causing a “left shift” as stimulated by complement C3a and G-CSF?
Leukocytosis in an acute inflammatory response
What is occurring when acute phase reactants reach max levels within 10-40 hours of infection (IL-1,IL-6)?
Increased levels of circulating plasma proteins in an acute inflammatory response
Which plasma proteins are present at increased levels in an acute inflammatory response?
- fibrinogen
- c-reactive protein
- amyloid A
- antitrypsin
What are the S&S associated with an acute inflammatory response?
- Increased in erythrocyte sedimentation rates (ESR)
- Somnolence
- Malaise
- Anorexia
- Muscle aches
Persistent inflammation from prolonged irritation.
Chronic Inflammation
How long does inflammation have to last to be considered Chronic Inflammation?
> 2 weeks
What causes prolonged irritation in chronic inflammation?
- toxins left after microorganisms killed in acute phase
2. microorganisms that survive and avoid clearance by acute inflammatory response.
What forms if macrophages are unable to limit the tissue damage or infection?
- Granulomas
2. Large antigen-antibody complexes