Innate Immune Protection (#1) Flashcards
What is innate immunity?
- non-specific defence mech that host uses immediately/within sev hrs after exposure to antigen
- keeps host alive until adaptive immune response can take over
What is 1st immune response?
inflammation
How long does innate immunity and early induced response take?
- 0-4hrs
- 4-96hrs
List characterisitics of innate immune system
- born with it
- v. fast (within hrs)
- ancient evolution - components found in invert, amoeba etc
- no memory - responds exactly same way each time
- uses handful of mol to recognise that infection is present
- induces + directs acquired/adaptive immune response
List components of innate immune system and when the are active
- Phys/anatomical barriers - not induced and happens all the time and prevents pathogens from entering
- Secreted compounds - secreted upon infection
- Cellular components - eliminate pathogen
What are goals of innate immune system?
- prevent entry of pathogen through openings and skin
- recognise pathogen
- recruit cells
- ingest pathogen
- induce specific immune response
How does skin act as protective barrier?
- dry, thick, protective outer layer made of keratin
List phys/anatomical barriers
- skin
- GI tract
- resp tract
- mucosal epi
List secreted compounds
- antibac compounds
- complement
- natural antibodies
- cytokines
List cellular components
- phagocytes
- NK cells
What is psoriasin?
prod anti-bac compound
Why can you get E.coli skin infection if you have burns?
- layer that makes psoriasin burnt away
How does resp tract act as phys/anatomical barrier?
- cells tightly packed together with tight junctions - diff for pathogens to enter cells
- cilia moves pathogens out of resp tract so can’t settle
- mucus to trap bacteria + eliminate by coughing/move bacteria out of resp tract
How does GI tract act as phys barrier?
- peristalsis keeps bacteria moving
- HCl prod
- low pH - bacteria not suited to + enz activated at that pH help to destroy bacteria
Describe mech and secreted protection
- eyes - blinking as mech way to remove pathogens
- tears - wash pathogens away
- tears, sweat, saliva contain lysopzyme which destroys bacteria walls
Describe int. protection (microbial competition)
- good bacteria in gut and skin compete with pathogenic bacteria for light, space + nutrients
Which pathogens does innate immune system recognise?
few highly conserved mol structures present in many diff microorg: pathogen ass mol patterns
What must PAMPS be?
- present in microorg but not host - immune system needs to diff between itself + host
- essential for survival of pathogen - so pathogen can’t mutate PAMP bc otherwise no longer good for immune recognition
Give e.g.s of PAMPs and where they are found
- lipopolysaccharide (from all gram -ve bacteria walls)
- lipoteichoic acid (from all gram +ve bacteria walls)
What is sig about polysacc and lipid A parts of LPS?
- polysacc: tells you what kind of gram -ve bacteria it is
- lipid A: PAMP part - same in all gram -ve bacteria
What are pattern recognition receptors?
- recognise PAMPs + send signal to host cell to upreg mol important in immune response
- determine self from non-self + which type of pathogen it is
List the PRRs and where they are found
- Collectins - float in serum
- Toll like receptors - within + on surface of cell mem, within vesicles within cell
- Nod-like receptors - cytoplasm
What are collectins and their structure?
- family of proteins present in sol
- collagen-like region + mannose binding-lectin region
What is the function of the diff regions of the collectins?
- collagen-like region interacts with effector parts of the immune system
- MBL region binds to sugar mol on surface of pathogen e.g. mannose
