Non-Specific Immune Defenses Flashcards
What are Non-Specific (INNATE) Defenses?
-1st and 2nd line of the immune system
-no specific responses (respond the same each time)
-No immune memory
-do not recognize antigens
-recognize danger patterns
-no lag time/instant defense
True or False:
Non-specific defenses often set off specific defenses
True, Non-specifc defenses can help your specific defenses
What is the first line of your immune system?
Non-specific barriers
What is the second line of your immune system?
Non-specific responses
-phagocytic cells
-neutrophils
-macrophages
-dendritic cells
-NK cells
-Inflammation (appropriate or non-appropriate)
-fever
-Interferon
-Complement
What is the third line of your immune system?
Specific Responses vs Antigens
-Cell-mediated response
-Humoral Responses
What do neutrophils do?
-perform phagocytosis
-do not present antigens
-die and form puss at infection site (pyogenic infections)
-can harm tissues when activated
-job is to be super deadly and kill everything around them (normal tissues and then themselves)
What do macrophages do?
-perform phagocytosis
-antigen presentation
What are dendritic cells?
macrophages in various tissues
What are interferons?
Cytokines cells that can secrete in response to infection
Why is complement important?
Important in getting the immune system activated quickly
What is a cell-mediated response?
T cells secrete cytokines or cytotoxins
What is a humoral response?
B cells make antibodies
What are epithelial surfaces?
skin or mucosal surface of the respiratory, gastrointestinal, and urogenital tract that are frequently exposed to microorganisms
What do macrophages, neutrophils and B cells ALL do?
-chemotaxis
-attachment
-phagocytosis
-digestion of the immune threat
-load peptides on MHC 11 proteins
-secrete pro-inflammatory cytokines
What does reduced phagocytes/phagocytic ability lead to?
predisposition to infection
What are Toll-Like Receptors (TLR)?
-PRR
-trans-membrane proteins on/in macrophages/dendritic cells
-bind dangerous molecular patters that are specific and ALWAYS associated with certain pathogens
-enable APCs to response in a non-specific way to danger patterns
-recognize patterns
-do not recognize antigens
What are PAMPs (Pathogen-Associated Molecular Patterns)?
-PRR binding targets that are critical to the particular microbe
-cant be eliminated or changed
-evolutionarily conserved
What are some examples of PAMPs?
-LPS
-gram neg bacteria in outer membrane
-lipoteichoic acid
-gram pos bacteria in cell wall
-flagella
-dsRNA (viral RNA)
True or False:
The specificity of TLRs can be altered.
False, the specificity can not be altered because they are a feature of non-specific immunity
True or False:
The specificity of TLRs can be altered.
False, the specificity can not be altered because they are a feature of non-specific immunity
What are the results of TLR binding?
-intracellular signaling
-cytokine production
-activation of other cells and responses
-Inflammation
-up-regulation of MHC proteins
Where are PRRs found?
-TLR = macrophages
-Complement = soluble protein in bloodstream and lymphatic fluid
What do PRRs respond to?
Danger patterns
What are the functions of PRR?
TLR = secrete cytokines by macrophages
Complement = bind danger pattern to initiate a complement cascade
*Secrete cytokines and induce MHC-11 proteins
What are NK cells?
-not antigen specific
-recognize infected/abnormal cells (too many or few MHC proteins secreted by the cell)
-not phagocytic
-extracellular killers
What are Eosinophils?
-not antigen specific
-secrete cytokines
-weakly phagocytic
-extracellular killers
-not antigen presenting cells
-rare in body
What is normal inflammation?
non-specific, localized response to…
-tissue damage
-infection/damage
What happens in normal inflammation?
-Cut allows bacteria beneath surface of skin
-damaged cells release histamine
-capillaries dilate: more blood comes to tissue making it more red and warm
-Fluid moves into tissue (edema) because capillaries are more permeable and causes swelling
True or False:
Systemic Inflammation is very dangerous
True
What does histamine do?
-causes redness
-causes swelling
-increases body temp
What does it mean if something is chemotaxis?
it is physically drawn by chemical attraction
True or False:
Inflammation is crucial to normal immune response
True
What do pyrogens do?
set macrophages off to produce pro-inflammatory cytokines
How does a fever happen?
-It is caused by pyrogens “fire makers” from outside of the body (ex: LPS and Lipoteichoic acid)
-Causes the release of various cytokines
-Cytokines travel to brain
-Portion of brain that regulates body temp is offset to increase body temp
True or False:
A fever does not benefit your immune system
False, can potentially be beneficial
What are alpha and beta interferons?
-Non-specific
-Early response
-Anti-viral responses in healthy cells (created in response to infection)
Where is complement produced?
produced in liver and released into bloodstream
Complement is normally inactive, but when it is active, it initiates a complement cascade. What are the results of a complement cascade?
-Inflammation: promotes phagocytosis
-Opsonization (coating): promotes phagocytosis/helps macrophages
-Microbe distribution
How do you activate a complement cascade through the classic pathway?
Complement proteins binding to bound antibodies
*Antigen-antibody complexes
How do you activate a complement cascade through the lectin pathway?
Complement proteins will bind to specific sugars that are on the surface of certain cells
*Doesn’t need antigen present to recognize danger pattern
(Microbial Surfaces)
How do you activate a complement cascade through the alternative pathway?
Complement proteins bind things that are foreign (ex: endotoxins)
*Microbial Surfaces
True or False:
Some complement proteins can become hydrophilic when activated
False, some can become hydrophobic
True or False:
Inappropriate cytokine production can cause shock
True, can result in either sepsis in the blood or toxins in the blood
What causes toxic shock?
Circulating toxins in the blood (endotoxins)
What causes septic shock?
Circulating microbes in the blood (septic = not sterile; asepsis= sterile)
*Caused by INFECTION
(leading cause of death in non-coronary ICU patients)
What is hypotension?
Blood pressure decreases
In sepsis, what does the body attempt to compensate hypotension with?
-HYPERVENTILLATION
-White blood cell count very high/very low
-Increased heart rate
-body temp
What is a result of sepsis?
multiple organ dysfunction and death
True or False:
Each hour delay in the administration of appropriate antibiotic therapy in sepsis patients = a 7% rise in mortality
True
