Host Defenses Flashcards
Host defense systems defend against..
microbes, worn out cells and mutant cells
Acquired immunity is also called what?
adaptive immunity
1st interface
barrier defenses, pattern recognition receptors
2nd interface
counter receptors
What are the cells of adaptive immunity?
T and B lymphocytes
The mechanism of generating diversity and specificaity in adaptive immunity depends on what?
rearrangement of receptro gene segments
Goal of aquired immunity
to gain specific recongition of foreign antigens and immmunological memory of infection
How long does it take to establish acquired immuntiy?
approximately 4 days
Innate immuntiy
evolutionary changes, lies mostly in inflammation triggered by neutrophils, machrophages and mast cells through dense receptors
defects in innate immmunity are ______ and were virtually unseen before antibiotic therapy
rare
The decision on whether or not to respond to ligands is made by…
the system of innate immune receptors
Innate immunity - PMN, macrophages, mast cells and NK cells
- Mainly involves white blood cells
Cyclic neutropenia in gray collies
- results in increased bacterial infections
- lack circulating neutrophils
- Caused by mutation in AP3β1 which affects melanocytes and bone marrow
- Because neutrophils have the shortest lifespan of cells affected their disappearance is more noticeable
Innate immunity - inflammation
Goal is to isolate the area and destroy invaders. remove debris and prepare tissues for healing
5 cardinal signs of inflammation
1) tumor - swelling
2) rubor - redness
3) Calor - heat
4) dolar - pain
5) loss of function
Acute inflammatory response and bone marrow
Leukocytosis
Acute inflammatory response and hyptothalamus
makes prostaglandin which causing fever. Also makes ACTH to stimulate the adrenal cortex which makes corticosteroids for the liver
Acute inflammatory response and liver
Corticosteroids along with signaling factors lead liver to make acute phase proteins–> CRP, SAA, MBL
Inflammation and acute bovine mastitis
Mammary inflammation can be caused by contagious or environmental bacteria. Milk contains clots and debris which makes it unprofitable. diagnosed through leukocytes in the milk. Treat with antibiotics
Pattern recognition receptors
receptors expressed on cell surfaces, in intracellular compartments or secreted into the bloodstream and tissue fluids
Strategies of Pattern recognition receptors
- opsonization - target microbes
- activate complement and coagulation pathways
- Phagocytosis
- Activate proinflammation
- induce apoptosis
Toll like receptors
intracellular and surface PRRS. Toll-like receptors (TLRs) are a class of pattern recognition receptors (PRRs) that initiate the innate immune response by sensing conserved molecular patterns for early immune recognition of a pathogen
Sepsis in neonatal foals
Dysregulated host response to bacterial infection
TLRs and LPS
TLRs recognize LPSs and bind to them. They cause severe inflammatory responses.
TLR via PAMP - intracellular TLRs
TLR7, TLR3, TLR8, TLR9
TLR via PAMP - extracellular TLRs
TLR1,2,6,4,5,11,10
How does LPS cause damage?
IL-1 (also called endogenous pyrogen, lymphocyte activating factor or catabolin) is a highly regulated cytokine. LPS indirectly activates inflammasome to cause inflammation. IL-1 creates cytokines that are very destructive and can go to brain, liver and bone marrow
