The components of immune system and introduction to innate immunity Flashcards
describe the action of microbes
microbes gain access, they enter and colonise and start to replicate and exit cells to infect other cells
how does skin acts as physical barrier
produce antimicrobial substances and has flora capable of blocking pathogen
name chemical secretions that act as physical barrier
tears with lysozymes, stomach secretions with low pH
what does spleen do
remove old and damaged RBC for holding some extra blood and recycling iron
why does immune respond to danger faster than adaptive
it identifies the threat and phagocytose it. It will also engage different PRR and lead cells to secrete cytokines
What are the signals needed for T-cell activation
antigen presentation by MHC to T cells and molecule on APC called CD80 and CD86 express to T cells
identify PAMPs in bacteria
lipoteichoic acid, peptidoglycan, lipoproteins, DNA, flagellin, lipopolysaccharide (only in gram negative)
what does PRR do
control activation of signal 2
where do TLRs locate and what they do
plasma membrane, activate MAP kinase, NF-kB and IRF pathway
what do TLRs recognise
nucleic acids, proteins and glycans
what do NLRs recognise
bacteria, viral and parasitic and fungal PAMPs
what do NLRs activate
activate caspase-1 mediated processing and activation of pro-interleukins IL-1B and iL-18
name the 5 signalling PRR
toll-like receptors, NOD-like receptors, C-type lectin receptors, RIG-like receptors, cytoplasmic DNA sensors (CDS)
what does PRR do
recognise PAMPs and lead to cytokine production and lysis of the bacteria
function of TLR-4
heterodimerise with MD-2 and with the help of LPS-binding protein and complements, LBP transfer LPS to CD14 which present it to TLR-4/MD-2. toll/IL-1 receptor domain in complex acan interact with TIR domains of adaptor proteins eg. MyD88
what do NOD-like receptors-3 do
NLRP3 oligomerise using adaptor protein ASC which brings procaspase-1 into close proximity using CARD domains to form inflammasomes and lead to production of IL-1B and IL-18
what is cellular heterogeneity
express a unique combination of PRRs and increase cell’s ability to recognise non-self
what do soluble PRRs do
enhancement of phagocytosis of PRR-bound PAMPs and resulting to lysis of microorganism
what do cell-associated PRRs do
phagocytosis of PAMP and associated microorganism and activation of immune encountering PAMP and produce cytokines to amplify response
what releases DAMPs and what does DAMPs do
necrosis cause release of alarmins (DAMPs) which activate the immune system, and are recognised by immune response
can PRR determine the adaptive immune response needed
no, can only determine nature of adaptive immune response during priming phase of adaptive because they lead to specific cytokines and chemokines production
function of cytokines
contraction of endothelial cells, activation of macrophages, differentiation of dendritic cells, migration of phagocytosis
what do pro-inflammatory cytokines do
local redness ,swelling, less blood flow and vascular permeability to allow neutrophils and other leukocytes to access infection site
what do NLRs activate
activate inflammatory response when PAMPs and DAMPs are encountered.
