Lect 2 - Innate Immunity Flashcards
To develop a basic understanding of the innate immune system incorporating the cells involved, cellular receptors, soluble mediators and an appreciation of the multiple layers of defence comprising the innate immune response (27 cards)
differentiate innate vs adaptive
innate is early
relies on molecules that differentiate things form our bodies
we all have the same receptors and molecules
what are the significances of adaptive
it can remember past, and gives us a faster response, also allows for vaccines
what are the components of the innate immune system
barriers - stop infection
cells - alert the system
circulating proteins - seek out different and mark them for the rest of IS
understand how barriers help protect us, provide some examples
mechanical - tight junctions stop things getting in, movement by cillia
chemical - fatty acid, low pH
microbiological - flora
describe what happens once the skin breaks
break skin, things get in
antimicrobial protein and peptide
setup system of activation as well as trying to heal
how does phalysosome kill
phagolysosomes have enzymes that make bleach to kill
what are some types of proinflammatory cytokines
TNF-α (tumour necrosis factor) • IL-1 (interleukin-1) • IL-12 • Type 1 interferons (interferon alpha and interferon beta) –induce antiviral state, increase MHC I
how do we recognise pathogens
PAMP - protein, n acid or lipid. they look different to normal.
compare the different steps in response by innate, early induced, and adaptive
innate: infection ->recognition by non-specific ->removal of infectious agent
early induced: infection->recognition of molecular pattern->inflammation and effector cells->removal of infectious agent
adaptive immune: infection->transport to lymphoid organs->recognition by B and T-cell->clonal expansion and differentiation of effector cell->removal of infectious agent
how does normal flora protect us from disease
- Competing with invaders for space and nutrients
- Producing compounds (bacteriocins) which kill other bacteria
- Lowering the pH so that other bacteria can’t grow
what are the cells of the innate immune system
- macrophages - monocytes
- neutrophils - granulocyte
- mast cells - unknown
- eosinophilic - granulocyte
- dendritic cells -granulocyte
- basophils
how do macrophages work
recognise microorganisms through their surface receptors
phagocytosis then occurs
phagosome then merge with lysosome
they also release cytokines to signal others
how do neutrophils work
neutrophils live in the blood, not present in normal tissue
they phagocytose and remove pathogen, without the assistance of adaptive immune system
if neutrophils is only found in circulation, how does it get to tissues
macrophages release chemical as a result of the pathogen, this activates receptors on the neutrophils and the cell wall to cause the neutrophil to leave the circulation and go to the inflamed tissue
how does phagolysosome kill
by releasing bleach
what are the dendritic cells
there are many types of dendritic cells
derived from the bone marrow, and live for a long time
their main function is to capture antigen and present if to lymph nodes
They act as messengers between the innate and the adaptive immune systems
activates T-cells and T-cell differentiation
eosinophils and mast cells
they release histamine
eosinophils important for protection against helminths
how does the innate immune system respond in inflammation
macrophages, sends for effector molecule via cytokine that start blood clot, more fluid, leading to vascular dilation
this gets neutrophils, eosinophils and lymphocytes
there are also lipid mediators such as prostaglandins and clotting factor
how do we recognise pathogens
pattern recognition receptors recognise pathogen-associated molecular patterns (PAMPs)
molecules have patterns on there surfaces
PRR fit with a distinct pattern that’s on the pathogen
the outcome depends on
effector cells used
receptor involved
describe toll like receptors and what they do?
TLR recognises microbial molecular patterns
it then sets off a signal cascade that also facilitates the initiation of acquired immune responses due to proinflammatory cytokines
what are MCH I
they are present on all cells, they bind to KIRs and stop NK cells from degranulating.
how does NK cells kill, and the 2 ways that it does it
NK cells kill by touching with the infected cell, and releasing granule which will either make holes causing lysis, or it will result in apotosis
what do NLRs do
NOD-like receptors, cytosolic receptors that recognise and alert cells to invasion.
activated by things such as peptidoglycan, RNA, toxins, and flagellum in cytosol.
how does the innate system deal with viruses
Various viral components
are recognised by PAMPs
in the virally infected cell
Trigger production of
interferons to try to
prevent spread of viral
infection to adjacent cells
Adjacent cells can put
special measures in place
that interfere with viral
replication
