Innate Immunity Flashcards
What are the 3 main functions of innate immunity?
initial defense response to pathogens
eliminates damaged cells and initiates tissue repair
controls adaptive responses
What is the general process of inflammation?
tissue is damaged and pathogen is introduced –> mast cells come in and release histamine –> vessels dilate and become leaky –> complement proteins leave vessels and attract phagocytes –> phagocytes engulf bacteria –> histamine and complement signaling stops –> growth factors and platelets stimulate healing
what do type I interferons do?
block viral replication w/in host cells
What do natural killer cells do?
kill virus-infected cells
How do innate immune cells tell between self and non-self?
have Pattern recognition receptors (PRRs) that recognize “pathogen-associated molecular patterns (PAMPs)”
What are the characteristics of pathogen-associated molecular patterns? (4)
- effective indicators
- unique to classes of pathogens
- often required for pathogen survival, so can’t be altered, suppressed, or easily hidden
- no structural similarity w/ self Ags
What are the 4 types of PAMPs shown in class?
gram-negative bacteria
gram-positive bacteria
mycobacteria = lipoarabinomanna
fungi = manno-proteins
What characterizes gram-negative bacteria?
What characterizes gram-positive bacteria?
gram - = thin peptidoglycan layer, porins and polysaccharides
gram + = thick peptidoglycan layer w/ techoic acids
What are the general properties of Pattern recognition receptors (PRRs)?
specificity
encoded in germline, limited diversity
nonclonal: identical receptors on all cells of same lineage
descriminate btw host and self
Where are the 2 main places you find TLRs?
on cell surface
in endosomes
What TLRs are found on the cell surface? what do they do there?
TLR 1, 2, 4, 5 and 6
recognize PAMPs of extracellular microbes –> inflammation
What TLRs are found in endosomes? What do they respond to?
3, 7, 8, and 9
respond only to nucleic acids of ingested microbes
What are the ligands of the TLR1:TLR2 heterodimer?
What cells carry this receptor?
lipopeptides and GPI
monocytes, dendritic cells, eosinophils, basophils, mast cells
What are the ligands of the TLR2:TLR6 heterodimer?
What cells carry this receptor?
lipoteichoid acid and zymosan
monocytes, dendritic cells, eosinophils, basophils, mast cells
What is the ligands of TLR3?
What cell carries this receptor?
double-stranded viral RNA
NK cells
