Exam 3 Lecture 26 Flashcards
(39 cards)
Innate immunity characteristics?
Evolutionarily conserved
Come from germline cells that we have at birth that encode receptors that induce antimicrobial responses
Fast-acting and non-specific
How do our cells recognize a threat?
They see MAMPs and PAMPs
Microbiol or Pathogen Associated Molecular Patterns
These patterns are molecularly conserved in the microbial world
Examples of a MAMP or PAMP?
DNA, RNA, Flagellin, Peptidoglycan, lipoteichoic acids, second messengers, LPS, fMET
What is a PRR?
Pattern Recognition Receptor
Each one will recognize a specific MAMP or PAMP aka portion of the microbe
Where are PRRs located?
Cell surface, in a cell compartment or in the cytosol
Non-specific example of PRR?
TLRs
NLRs
Inflammasomes
Specific Example of a PRR?
TLR4 located on the cell surface of macrophages, monocytes, mast cells, dendritic and intestinal epithelium.
Recognizes LPS and heat shock proteins
Where are inflammasomes located?
In the cytosol
What is so bad about LPS?
Also called endotoxin and is made by gram-negative bacteria.
No Vaccine can be made
Boiling doesn’t kill
The primary cause of Gram-neg infections
Released when Gram neg bacteria die
Causes inflammation and septic shock and death in high quantities
The main reaction to PRR?
Cytokines
True/False Some cytokines are cleaved and processed in the cytosol by inflammasomes before being released.
True
What are chemokines?
A cytokine that makes a gradient leaning neutrophils and macrophages to the infection site
Extravasation?
How neutrophils get fro the bloodstream to the infection site
Bradykinin and histamine are released to increase blood vessel permeability causing vasodilation.
Causes swelling and redness at infection site
Steps of extravasation?
- Cytokines activate selectins (ICAM and VCAM) on endothelial of vessel
- Selectins grab neutrophils and roll along the vessel
- Integrins bind ICAMand VCAM to the white cell/neutrophil
- Neutrophill squeezes through vasodilated vessel wall
How is a fever made in response to LPS or and infection?
- Monocytes activate pyrogenic cytokines that travel to the brain endothelium
- Elevated set point
Why fever?
Heat stress for invading microbes
Decreases iron availability (which microbes need)
How do cytokines affect iron availability?
Decrease it by increasing production of an iron storage molecule to keep it away from invading microbes
What happens in Septic Shock?
Systemic wide vasodilation which causes low blood pressure
Happens in large veins and smaller vessels
Inadequate blood flow in small vessels means organs and tissues don’t get O2
Death
True/False Septic shock is mediated by the host and independent of the microbe
True
Could injection or purified LPS or heat-killed bacteria cause Septic Shock?
Yes
Other diseases caused by inflamation?
Autoimmune diseases such as Crohns or lung and vascular autoimmunity
What causes a physical barrier to commensal microbes in the gut and colon?
Mucus protects the pits/crypts and there are stem and paneth cells at the base of the crypts/pits in gut and colon epithelium that make antimicrobial mediators
Mucus can be broken down by inflammation
What do pathogens do if they get into the cell?
Disrupt actin, cytosolic delivery of ligands and enzymes, make pores, replicate, inflammasome reaction, cytokine induction cell death
Um wreak havoc and avoid host defenses to further their life Duh
Methods they use to avoid detection?
Subvert- disrupt detection pathways
Host and bacteria can go back and forth- microbe subverts host figures it out and so on
Evade- mask there presence by capsule or changing the structure of MAMPs such as Y. pestis
