cooperation Flashcards
Endo cytosolic antigens 1) name the processes 2)name the enzymes
Class 1 MHC 1) Synthesis of class I, Assoc of peptide with class I, Transport from ER, Expression of MHC 1 peptide at cell surface 2) Peptide transporter protein, TAP and proteasome, which degrades antigen to peptides
exogenous antigens 1) name the steps 2) another name for the class 3) how does peptide enter ER
1) Synthesis of class II, assembly of classII (invariant li chain blocks peptide binding site in Er), Transport from ER, Peptide associates with class II, displaces li, Expression of MHC 2 2) Class 2 isknown as APCs 3) The antigen enters via endocytosis, protein degradation
How are T cells activated
When their TCR binds peptide antigens displayed on MHC molecules
CD8+ cytotoxic lymphocytes present what class?
class 1, so from endogenous antigens
CD4+ Helper T lymphocytes present what class?
Class 2 MHC
The antigen presenting cell must do what to activate naive T cells?
Acquire and process antigen in compartments which gain access to MHC1 and MHC2 pathways
What are the 3 signals for the effective activation of naive T cells
1) Present MHC associated peptides to T cells 2) Provide co stimulation for T cell expansion 3) Induce T cell differentiation
What are the best antigen presenting cells?
Dendritic
How do APCs become activated?
By binding PAMPs
Once the APC has become activate, what happens?
They migrate to local lymph nodes to present the antigen to T cells
Dendritic cells in non inflammed tissues are highly efficient at what but are also poor what and why
Efficient at capturing an antigen but very poor as stimulators of naive T cells. They are active in noticing their surrounding environment due to mannose and FcR receptors. But migration to the draining lymph nodes is restricted, low level of MHC 2 on plasma membrane. Secrete TGF beta
Dendritic cell maturation is essential for what 1)initiated how? 2) signalling occurs following ligation of?
for activation of naive t cells 1) initiated by binding of pathogens 2) signalling by PRR on the DC following ligation with molecular patterns PAMPS on pathogens
DC maturation event are indued by?
PAMPs
Binding PAMPs to dendritic cell PRR induces what 7 things
Migration of DC to the lymphoid tissue via lymphatics. Inreased antigen processing. Increased surface expression of MHC 1 and 11. Increased surface expression of adhesion moelcules. Expression of costimulatory molecules (cd80, cd86). Secretion of cytokines, TGF beta, IL6, IL12
Maturing DCs loose capacity to what?
capture antigen
What are the 3 signals of licensed DCs
Display pathogen peptides on MHC -S1 upregulate expression of adhesion (eg ICAM-1) molecules and express co- stimulatory molecules (eg CD80, CD86) – Signal 2 Secrete selected cytokines Signal 3
Adhesion between T cells and APC is essential and how does this ocur and give example
Involves specific receptor ligand interactions and these result in firm binding. ICAM1 on APCs and LFA1 on T cells
Descrive the activation of CD4 T cells due to the induction of CD80 and CD86, so describe the first 2 signals
signal 1) Binding the TCR to MHC peptide signal 2) Ligation of CD28 on the T cells by CD80, CD86 on the mature dendritic cell provies signals to induce activation and proliferation of the naive antigen specific T cell
After recieiving signal 1 and 2, the activated CD4 Tcell now 1) expresses what? 2) Expresses and secretes what? 3) what is signal 3 4) Signal 3 facilitates activated CD4 TH to what?
1) CD40L 2) Expressed IL2R and secretes IL2 and proliferates 3) Signal 3, differentiates to perfom its effector function so it helps neuts, B cells, CD8 T cells 4) causes the T helper cells to differentiate along several possible pathways
Describe the pathways for the T helper cell
