Ch 16 Innate immunity Flashcards
Which cells release interferon alpha?
Host cells infected with a virus
What does interferon alpha signal for?
- It signals for neighboring cells that there is a viral threat in the area
- This signals for them to release their own antiviral proteins for protections
- Also signals NK cells to come help
What phagoctye arrives early or 1st to an immune response?
Neutrophils
Which phagocyte arrives later to help fight pathogens and clean up debris?
Macrophages
What compliment does the activation cascade coverge at?
C3
What are the shorthand terms for the 2 activated complement fragments?
C3a and C3b
What are some characteristics of the innate immunity?
- Nonspecific immunity
- Always present and working
- Protective mechanisms are mostly at a constant level
- No specific molecular recognition of pathogens
- No memory of pathogens
- Contains and destroys most pathogens
- Forms the first two lines of defense: Skin and mucous membranes; NK cells, phagocytes, fever, inflammation
What are some characteristics of the adaptive immunity?
- Specific immunity
- Inducible
- Up-regulatable
- Provides delayed responses
- Uses molecular recognition to target
specific pathogens - Has memory of specific pathogens
- Uses molecular recognition
- More powerful than innate immunity
- Third line of defense
- lymphocytes
Does first line innate immunity involve the activation of immune cells or immune proteins?
It does not, 1st line of innate immunity ONLY uses skin epithelial cells within mucus membranes
No immune cells or proteins
1st line of innate immunity Physical factors include:
- Skin and membranes
- Saliva
- Vomit
- Diarrhea
- Ciliary escalator sweeps debris out of
trachea - Urine
- nose hair
1st line of innate immunity CHemical factors include:
- Lysozyme (sweat, tears)
- HCL and the protease pepsin (stomach)
- histatin (Saliva contains antifungal compound)
- Sebum forms oily, acidic film that covers the body
Know which immune cells are derived from the myeloid stem cell
- Mast cell
- Eosinophil
- Basophils
- Neutrophil
- RBC
- Megakaryocyte
- Platelets
All of the following are derived from the myeloid stem cell EXCEPT
Neutrophil
Macrophages
Basophil
Eosinophil
Macrophages
Know the three innate immune cells that are the common phagocytes
Neutrophils
macrophages
dendritic cells
Which of these immune cells is known as the ‘best’ phagocyte?
- Macrophages
What are TLRs?
Receptor proteins on the surface of neutrophils
How do TLRs assist with immune defenses?
It signals new Neutrophils coming in to attack pathogens
What type of microorganism is specifically targeted by eosinophils?
Large organisms such as helminths (parasites)
How are basophils and mast cells similar?
Both are antigen-presenting cells
Both contain granules that contain signaling molecules that promote immune response
how are basophils and mast cells different?
Basophils:
- are found in blood
- Produced by bone marrow
Mast cells:
- are found in tissue
Which cell type found in the blood can become a macrophage?
Monocytes in the blood become macrophages as they
enter the tissues
How is a fixed macrophage different from a free macrophage?
Free macrophages: roam tissue and gather at infection
sites
Fixed macrophages: are embedded in body tissue
What is a natural killer cell?
granules (small particles) with enzymes that can kill tumor cells or cells infected with a virus
How is a NK cell different than the other innate cells?
- Kills without phagocytosis
- Kills without molecular recognition of foreign organism
How do perforin and granzymes kill target cells?
Perforin – creates holes in host cell (causing lysis)
Granzymes – causes apoptosis (programmed cell death)
What is the basic function of a dendritic cell?
Primary antigen-presenting cell
links to adaptive immune response
How are inactive complement proteins activated?
in response to foreign cells by means of antibodies or lectin cause activation of C3 protein in complement which then activates cascade
Which organ produces complement proteins?
Liver
Which specific complement protein is at the end of the activation cascade?
C9
What are the 3 immune responses that occur after the complement activation?
opsonization
inflammation
cytolysis
What is the end result when the complement cascade from C3 to C9 is completed?
Cytolysis caused by membrane attack complex
What are the names of a couple enzymes that inhibit viruses? (found on the interferon ppt slide
Proteases and nucleases
Why are antimicrobial proteins a good defense against pathogens?
What are the five cardinal signs of inflammation?
Pain
Redness
Immobility
Sweeling
Heat
What is the result of histamine release at the site of injury?
- Histamine increases fluid delivery
- Vasodilation of local arterioles
- Increases permeability of blood vessels
What is the purpose of forming a blood clot as part of inflammation?
- Blocks local vessels
- Decreases blood flow from the site
- Slows blood flow at site
- Allows fluid to accumulate at site of response
Describe how immune cells leave the bloodstream and travel to sites of infection. What are the three formal terms?
margination
diapedesis
chemotaxis
Describe what occurs during margination?
immune cells move to edges of vessel
describe what occurs during diapedesis
immune cells squeeze between endothelial cells
describe what occurs during chemotaxis
immune cells travel to source of histamine
What is a pyrogen?
A chemical compound induces fever
Why is a fever (below 104 F) beneficial?
Fever catalyzes immune cell functions while inhibiting microbial growth
What is opsonization?
improved phagocytosis
What is cytolysis?
The rupturing of a cell due to excess internal pressure
How does a phagocyte destroy an engulfed microorganism?
- Chemotaxis: Phagocytes follow chemical trail to site.
- Adherence: Phagocyte membrane attaches to foreign cell.
- Ingestion: Pseudopodia surround the target and fuse.
—Engulfed target= phagosome. - Digestion: Phagosome is fused with a lysosome to form the phagolysosome.
Describe the difference between a phagosome and a phagolysosome.
Phagosome: Engulfed target
Phagolysosome: fused with a lysosome during digestion
What is resistance?
Ability to not get infected
What is susceptible?
