Innate Immunity 4 Flashcards
can receptors be homodimers or heterodimers?
both
how do receptors dimerize?
by ligands aka the pathogen
what are 2 types of receptors that are heterodimers?
TLR2 and TLR4
what is the only molecule that results from PRR?
cytokines
what are 5 cytokines that cause inflammation?
- IL-1
- IL-6
- IL-8
- TNF-alpha
- IL-12
what are 2 cytokines that cause antiviral effects?
- IFN-alpha
- IFN-beta
what does IFN stand for?
interferon
what are 2 types of chemokines?
- CC chemokines
- CXC chemokines
what is different about CC and CXC chemokines?
different location of the 2 cysteine residues
what are 3 effects of PRR signaling?
- cytokine production
- increased expression of costimulatory molecules
- enhanced migration to regional/secondary lymphoid
what are 2 costimulatory molecules produced by PRR signaling?
- B7.1/CD80
- B7.2/CD86
what do B7.1/CD80 and B7.2/CD86 do?
provide SIGNAL 2 to T cells in lymphoid tissues
where are costimulatory molecules located?
on dendritic cells
why are costimulatory molecules located on dendritic cells?
because they need to present to lymphoid tissue
how does PRR signaling cause enhanced migration to regional, secondary lymphoid organs?
upregulates specific adhesion molecules
what is the result of migration to regional, secondary lymphoid lymphoid organs?
T cells activate
what are the steps of Type I IFN signaling?
- IFN secreted upon PRR signaling
- IFN binds to receptors on surrounding cells
- triggers signaling in nucleus
- transcription of genes that inhibit viral replication
- halt/slow virus infection
what type of molecules causes migration of dendritic cells?
costimulatory molecules
what happens if transcription factors for IFN cannot reach nucleus?
everything in cytoplasm works normally to produce the transcription factor, but it remains in the cytoplasm and cannot activate IFN genes
what is the term for migration of neutrophils and phagocytes to the site of inflammation?
chemotaxis
what type of cells do adhesion molecules recruit?
monocytes
describe how monocytes move to site of infection by adhesion molecules?
adhesion molecules line the endothelium and bind the monocyte
when the monocyte receives the chemokine signal, the monocyte migrates into the surrounding tissue and differentiates into an inflammatory monocyte at the site of infection
what are the 3 types of adhesion molecules?
- selectins
- integrins
- immunoglobulin superfamily
are all adhesion molecules throughout the body?
different types of adhesion molecules in different tissues
how do leukocytes move thru the body?
adhesion molecules WEAKLY bind the leukocyte so the cell can roll across the endothelium thru the bloodstream
what are 4 symptoms that result from the recruitment of leukocytes?
- heat
- redness
- swelling
- pain
why does icing help with inflammation? and why should you not ice for too long?
reduces vasodilation but don’t ice for too long bc could prevent immune cells from functioning
what is diapedesis?
when cell crosses from the lumen of a vessel btwn endothelial cells into surrounding tissues
what are the 4. steps of cell migration?
- rolling adhesion along endothelial cells
- tight binding at adhesion molecules, held in one place
- diapedesis (migration into tissue)
- migration towards high [chemokines] where pathogen is
when are more adhesion molecules expressed at the endothelium?
when cytokines/chemokines are released, they bind endothelium to cause more adhesion molecule expression
what happens to the blood vessel upon migration?
vasodilation
when does arthritis/loss of function occur?
with severe/chronic inflammation
