1-25 Innate Immunity Flashcards
role of TLRs in recognition of pathogens
TLRs are found on macrophages and dendritic cells
recognize singals associated with invading pathogens (LPS, peptidoglycan, yeast, mycobacterium)
many types, all share common signaling pathways
binding of antigen to these receptors creates signaling pathways that result in the immune cell releasing cytokines (interferon, interleuken, etc..)
explain the role of cytokines produced by the reaction to pathogens
At the site of infection, macrophages release inflammatory cytokines that collectively induce a state of inflammation.
TNF-alpha, IL1, IL6
TNF-alpha
macrophage secreted cytokine - stimulates T and B cells, induces fever.
primary mediator of septic shock
IL1
macrophage secreted cytokine - interleuken-1
released as a pro-cytokine, cleaved to mature form by the inflammasome which is assembled in response to inflammatory signals
IL-6
macrophage secreted cytokine - induces fat/muscle cell to metabolize, make heat and raise temperature in infected tissue
combined effect of IL1 and TNF-alpha
increase blood vessel permeability - enables effector cells and fluid containing molecules to enter tissue
LPS segments
polysaccharide end - often antigenic and determinant of the O antigen
hydrophobic lipid rich end - contains Lipid A. the actual endotoxicity.
LPS pathology
septic shock, disseminated intravascular coagulation, acute respiratory distress syndrome
septic shock
endotoxin shock, associated with gram - bacteria
CXCL8
macrophage secreted cytokine - receuirts neutrophils from blood and guides them to infected tissue
IL-12
macrophage secreted cytokine - recruits/activates NK cells that also excrete cytokines to strengthen macrophage response
cytokines in liver
activate complement opsonization
cytokines in bone marrow
neurotrophil mobilization for phag
cytokines in hypothalymus
increase body temp (decrease viral/bacterial replication)
cytokines in fat/muscle
protein and energy mobilization to generate increased heat (decrease viral/bacterial replication)
TLR-4
recognizes?
carried by?
recognizes and reponds to LPS.
macrophages, dendritic cells, mast cells, eosinophils
Toll receptors are part of _______ of bacteria/viruses/fungi. Lead to production of____
innate recognition
of a bunch of molecules that are used by our body. High quantities activate lots of the toll receptor 4, leading to production of lots of tnf and IL1, which are potentially lethal at high concentrations.
The answer to every tetanus question will likely be
administer tetanus toxoid (booster)
inflammasome
assembles and reacts to inflammatory singals such as ATP. Resulting in activation of caspase which cleavse and releases the cytokine IL1
superantigic toxins
Superantigen toxins bind to outside the variable region on the t-cell receptor. Bind outside of cleff of MHC. Bind to way more t-cells and most antigen presenting cells. Bring lots of t-cell and presenting cells together. Stimulate t-cells to be activated. t-cell populations get exhausted.
causes toxic shock
why are the symptoms of toxic shock and septic shock similar?
toxic shock(superantigen) and septic shock(endotoxin shock from LOS) both arise from activation of the same cytokines (TNFalpha, IL1)