The components of immune system and introduction to innate immunity

Question 1

describe the action of microbes

Answer 1

microbes gain access, they enter and colonise and start to replicate and exit cells to infect other cells

Question 2

how does skin acts as physical barrier

Answer 2

produce antimicrobial substances and has flora capable of blocking pathogen

Question 3

name chemical secretions that act as physical barrier

Answer 3

tears with lysozymes, stomach secretions with low pH

Question 4

what does spleen do

Answer 4

remove old and damaged RBC for holding some extra blood and recycling iron

Question 5

why does immune respond to danger faster than adaptive

Answer 5

it identifies the threat and phagocytose it. It will also engage different PRR and lead cells to secrete cytokines

Question 6

What are the signals needed for T-cell activation

Answer 6

antigen presentation by MHC to T cells and molecule on APC called CD80 and CD86 express to T cells

Question 7

identify PAMPs in bacteria

Answer 7

lipoteichoic acid, peptidoglycan, lipoproteins, DNA, flagellin, lipopolysaccharide (only in gram negative)

Question 8

what does PRR do

Answer 8

control activation of signal 2

Question 9

where do TLRs locate and what they do

Answer 9

plasma membrane, activate MAP kinase, NF-kB and IRF pathway

Question 10

what do TLRs recognise

Answer 10

nucleic acids, proteins and glycans

Question 11

what do NLRs recognise

Answer 11

bacteria, viral and parasitic and fungal PAMPs

Question 12

what do NLRs activate

Answer 12

activate caspase-1 mediated processing and activation of pro-interleukins IL-1B and iL-18

Question 13

name the 5 signalling PRR

Answer 13

toll-like receptors, NOD-like receptors, C-type lectin receptors, RIG-like receptors, cytoplasmic DNA sensors (CDS)

Question 14

what does PRR do

Answer 14

recognise PAMPs and lead to cytokine production and lysis of the bacteria

Question 15

function of TLR-4

Answer 15

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

Question 16

what do NOD-like receptors-3 do

Answer 16

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

Question 17

what is cellular heterogeneity

Answer 17

express a unique combination of PRRs and increase cell’s ability to recognise non-self

Question 18

what do soluble PRRs do

Answer 18

enhancement of phagocytosis of PRR-bound PAMPs and resulting to lysis of microorganism

Question 19

what do cell-associated PRRs do

Answer 19

phagocytosis of PAMP and associated microorganism and activation of immune encountering PAMP and produce cytokines to amplify response

Question 20

what releases DAMPs and what does DAMPs do

Answer 20

necrosis cause release of alarmins (DAMPs) which activate the immune system, and are recognised by immune response

Question 21

can PRR determine the adaptive immune response needed

Answer 21

no, can only determine nature of adaptive immune response during priming phase of adaptive because they lead to specific cytokines and chemokines production

Question 22

function of cytokines

Answer 22

contraction of endothelial cells, activation of macrophages, differentiation of dendritic cells, migration of phagocytosis

Question 23

what do pro-inflammatory cytokines do

Answer 23

local redness ,swelling, less blood flow and vascular permeability to allow neutrophils and other leukocytes to access infection site

Question 24

what do NLRs activate

Answer 24

activate inflammatory response when PAMPs and DAMPs are encountered.

Question 25

explain the cascade after PAMP-PRR interaction

Answer 25

resulting in activation of NF-kB or interferon-regulatory factors (IRFs) and lead to transcription of genes that mediate inflammation

Question 26

what does activation of IRFs lead to

Answer 26

transcription of IFNs and thus antiviral response