Immunology Flashcards
Describe briefly the innate immune system
will recat to nything foreing made up of
complement
Myeloid progenitro cells (neutorpgils, macrophagses, dendiritc cell, basophills, mast cells, eosinohpils)
Lymphoid line ( natiral killer cells)
Describe briefl Adaptive immuntiy
Lymphoid line
lymphocytes
mostly live in lympahtic system
T cells and B cells
what are PAMPs
Pathogren associated molecular patterns
recognsied by pettern recogntiion receptors on innate immune cells
what are DAMPs
Damage associated moelcular pattern- released by body cells whe dmaaged- binds to innate cells resulting in release of cytokines to promte
which 3 immune cells are involed in Phagocytosis
Macrophafes,. neutrophils, denditic cells,
which cells are professional antigen presenting cells
Macrophages, dendriitc cells, B cells
Will cells of adaptive immunity bind to any antigens?
Antigen msut be presented on an MHC molule in order to be reocgnsied by adpative immune system
Describe how Antigen presenting cell present antigens to Cd4 T helper cells?
PAPC- opresent antigen on MHC II
if the antigen matches the T cell receptor then they can bind
but alos need
B7 on antigen presentincell—-> Cd28
both needed to stop inapproproiate T cell activation
where would we find MHC I ? in what cells?
any nucleated cell hs MHC I molecule on itn surface
describe the role of cytotoxic T cells (CD8+) and what activated them
Cytotic CD8 T cells have
- Cd+ moelcule on surface
- TCR and CD28 molecule
- not activated by MHC II profresional on antigen cell
- need to be presetned on MHC I
- if the cell also has B7 (bind to cd28 on T ceell)
- will kill the cell
what is the purpose of MHC I
take proteins in cytosl made by cell and present on the surface to passing cytotoxic C8 + cells
Cd8+ cell will react if cel producing viral proteins thta have been presented
need B7 (cd29 intercation too to get acitivation
What happens if a virus is stopping the production of MHC I in a cell so it cannot present viral proteins ?
Naturl KILLER CELL- CHECK to see if cells are producting MHC I if not will kill assume virus infected cell
will also work on Cancer cells (but cancer cells ahve ways aroundt this….)
Describe the Process of T cell maturation (once activated)
virgin—> activated ( T cell maturation)
Antigen on MHC II on APC travels to lymph node (denditice cell)
binds to
TCR- MCHII
B7—-> Cd28
with cytokines and other signals becomes activated
depending on what type of cytokines and antigne will determine what type of T cell it will become
what are
Th1
Th2
Th17
produced in response to during maturation
TH1- bacteria and viruses
Th2- parasites and bacteria (gut linign)
th17 fungi
describe the maturation of LKiller T cell Cd8
infected cell presenting antigen on MHC1
need helepr T cell to bind killer T cell tonget full response
how does the Cytotoxic T cell kill a cell
uses ligand- fas ligan- apoptosis
or perforin- punch holes in cell mebrane
Fab= antigen bindign region
each B cell amkes own ntigbodies can relasied into ciruclation to bind to pathogens, opsonise them or activate complement
Describe T cell independent B cell acitvation
B cell comes across antigen- that has a repeated pattenr, binds to and link to many times
Describ T cell dependent B cell activation
need more than just on B cell receptor activation
- B cell will act as a Antigen presenting cell
- internalises antigen presents on MHC II cells
- Cd 40 on B cell
- Acitvated T hleper cell binds to niave B cell
- cd40—-> Cd40 ligand ( Th cell)
- MHCII+ antigen —-> TCR
- with right combination of cytokines
- activate the B cells
Describe B cell maturation
(3 processes)
Class switching-
constant region chaneg of antigen- specific task
somatic hypermutation-
B cell multiples- geerntes erros, small changes in BCR - Amntigenfit fine tunes- Fab region becomes more specific
Memeory vs plasam
Differences between MHc class I and MHC class II
- MHC I found all all nucleated cells
- MHC II found on professiona APCs
- MHC class II -presenst larger peptides (14-18 AA) MHC I (8-10 AA)
- types of T cell acitvaed
- MHCI - CD8 T cells
- MHCII- Cd4 T cells
- types of patogens
- MHCI- intracellular pathogen viruses
- MHCII- extracellula pathgoen- bacteria
Describe the process of MHC class I antigen presentation
- MHC class I alpha chain bidns to clanexin in ER util B2 macroglobulin binds to the alpha chains- calnexin released
- MHCII then binds to a complex of chaperone proteins
- Erp57, calrectiulin, tapasin
- hlep to stabilsei and positon MHC I and to TAP ( transport protein involed in antigen processing)- this forms peptide loading complex
- non self or self proteins found in cytosols of cells are degraded by proteosome into peptide fragments- these enter ER via TAP 8-10 AA long
- binding of peptide fragment to MHC class I- release of chaperone proteisn- ecport of MHC I: antigen complex to surface
MHc class 2 process of antigen presentation
- MHC II found in ER attached to an invariant chain
- stops peptide frgaments binding
- Ivariant chain cause MHC milecule to leave Er in vecsicle
- vesciel then enter endocytoci pathwya becomes more acicdic
- drop in pH loss of invariant chain
- endocytosed molceculs brokend down into AA 14-18 AA long
- CLIP remaisn blocking bidning of peptide
- HLA-DM, binds to MHC, removes CLip so antigen can bind
- MHC antigne complex can then be expressed
