Chapter 16: Nonspecific Immunity Flashcards
Innate immunity
- Nonspecific immunity
- Always present and working
- No memory/recognition of pathogens
- Forms first two lines of defense:
*Skin and mucous membranes - NK cells, phagocytes, fever, inflammation.
-Contains and destroys most pathogens
Adaptive immunity
-Specific immunity
-Inducible
-Provides delayed responses
-Has memory/recognition on to target specific pathogens
-More powerful than innate
-Third line of defense
First line of defense: Barriers
> > Physical:
- Skin, saliva, urine flow, vomit, diarrhea, nose hairs, ciliary escalator (trachea)
> > Chemical:
-Lysozyme (sweat, tears)
-HCL and protease pepsin (stomach)
-histatin (Saliva contains antifungal)
-Sebum film that covers the body
Second line of defense: Immune cells, proteins, inflammation
- Neutrophils
- Eosinophil
- Basophil
- NK cell
- Macrophages
- Dendritic cells
»Proteins: complement
- Neutrophils:
Granulocyte. First to arrive. Produces toxins to kill.
* Phagocyte. *
- Basophil:
Granulocyte. Signaling. Found in blood. Produced in bone marrow.
A similar cell found in tissue: Mast cell (also for signaling)
- Eosinophil:
Granulocyte.
Targets large pathogens (helminths) parasites.
Releases histamine.
- Natural Killer cell:
-Granulocyte.
Releases: Perforin, granzymes -Kills abnormal (virus infected) host (my) cells without phagocytosis or molecular recognition.
How to perforin and granzymes kill target cells?
> > Perforin: Creates holes in host cell, causing lyses
> > granzymes: apoptosis: controlled cell death
- Macrophages:
*Best Phagocyte.
2 types:
-Free=roams around to infection sites
-Fixed= stays in tissue
Antigen presenting cells= links to adaptive immunity
What cell found in the blood can become a macrophage?
Monocytes; they become macrophages as they enter the tissues.
- Dendritic cells:
*Phagocyte (eats pathogens)
Primary antigen presenting cell.
Move to immune organs.
Proteins: complement
> Activation cascade always converges at C3.
*C3–> C3A & C3B
Does first line innate immunity involve the activation of immune cells or proteins?
No, the first line of defense only used skin epithelial cells within mucus membranes. No cells or proteins.
Which immune cells are derived from the myeloid stem cell?
-Neutrophil, Eosinophil, Basophil, dendritic cells, mast cells.
What are TLRs?
Toll-like receptors.
Receptor proteins on surface of neutrophils. They recognize microbes. Signals to kills pathogen.
PAMPS
Pathogen associated molecular patterns
How are inactive complement proteins activated?
In response to foreign cells or lecting cause activation of C3 protein.
Which organ produces complement proteins?
Liver
What are the shorthand terms for the 2 activated complement fragments?
C3a and C3b
Which specific complement protein is at the end of the activation cascade?
C9
What are the three immune responses that occur after the complement activation?
- Opsonization: Coat (makes it sticky) of C3b enhances phagocytosis.
- Inflammation: by activating mast cells. Blood vessels become permeable and chemotactic agents attract phagocytes to area.
- Cytolysis: 12 C9 cells (surround) attack a microbe, making it burst.
What is the end result when the complement cascade from C3 to C9 is completed?
MAC
Which cell releases interferon alfa?
Virus infected cells:
-Tells neighboring cells to be more resistant to viral infection.
*proteases/nucelases to INHIBIT viruses
*AVP: antiviral proteins
-Attract NK cells to come help.
