2. Innate immune responses Flashcards
4 things which make skin a good barrier to infection
- acidic pH ; 4-5.5
- desquamation
- sentinel cells (macrophages + dendritic cells) embedded in membrane
- sweat contains microbicidal FA to break down bacterial cell walls
3 things which make mucous a good barrier to infection
- thick
- flora - compete with bacteria
- ciliated/peristaltic movements
2 physiological barriers to infection
- pH
2. temp >37
what protein is produced in tears? what is its funtion?
lysosome - breaks down bacterial cell wall
what celll produces defensins ? in what substance?
neutrophils - sweat
function of defensins
antimicrobial
2 functions of lung surfactacts
- lubricate surface to prevent infection
2. acts as opsonin for phagocytosis
name 2 opsonin proteins
- C-reactive protein
2. Mannose-binding protein
function of lactoferrin and transferrin
Binds iron to microbe - iron is toxic
what protein induces fever
IL-1
3 functions of complement
- lysis
- opsonisation
- inflammation
which 3 cells conduct phagocytosis?
- macrophage
- monocyte
- neutrophil
2 functions of dendritic cell
- produce cytokines - inflammation
2. stimulates adaptive IS
when are mast cells activated?
when microbes attach to receptors/Ab
2 functions of mast cells
- inflammation
2. cytokine and proteolytic enzyme release
function of NK cells
kill infected host cells
3 mechanisms of innate immunity
- phagocytosis
- target cell lysis
- inflammation
steps of phagocytosis - innate
- cell recognisie PAMPS/DAMPS with TLR
- phagocytotic membrane engulfs microbe
- phagosome fuses with lysosome - phagolysosome
- NO, ROS, proteolytic enzymes released to kill microbe
5 types of cellular receptors in the innate immune system
- TLR
- NLR
- CDS
- RLR
- CLR
which cellular receptor is endosomal? what does it recnoginise?
TLR - nucleic acids
which cellular receptors are on the cell membrane? what do they recognise?
TLR = bacterial cell wall lipid CLR = microbial polysaccharide wall
which 3 receptors are cytosolic (give full names)
- NOD like receptor
- Rig like receptor
- Cytosolic DNA sensor
what do NLR respond to? what do they cause the activation of?
peptidoglycan bacterial cell wall - activate Transcription factor for inflammation
Which receptor responds to viral RNA?
RLR
which receptor responds to microbial DNA?
CDS
describe structure of TLR
- ligand binding doman with leucine rich motifs
2. can either be double or single stranded or lipopolysaccharide
function of TLR when activated
Cause transcription which causes the increased expression of cytokines which leads to inflammation and the adaptive response
what is the role of phagocytosis in the adaptive response?
antigen presenting cells
which type of cells undergo cell lysis?
NK cells - large granular lymphocytes
2 types of cells which undergo cell lysis
- viral infected host cell
2. phagocytosed microbe
describe steps of cell lysis of a viral infected host cell
- NK cell detects viral proteins
2. NK cell delivers enzymes to kill the cell
describe steps of cell lysis of phagocytosed microbe
- macrophage with engulfed microbe releases IL-12
- NK cells detects IL and attaches to the microbe
- NK cell releases IFN-y
- instructs macrophage to kill pathogen
describe the inflammation response in the innate response
- mast cells, dendritic cells and macrophages recognise damaged cell - release cytokines and mediators (histamine and heparin)
- mediators cause increased permeablity of the blood vessel
- causes entry of complement proteins into tissues AND entry of leukocytes into tissue
- leukocytes destroy microbes and induce more inflammation and repair
2 signals from innate system which induces the adaptive system
- recognition of antigens by lymphocytes
2. cytokines
