Linking: Visualizing Antigen presentation Flashcards
T OR F: dcs can only present 1 antigen at a time
False = can present multiple antigens at once
Describe sequence of dc activation/T cell activation
PRRs activated in peripheral tissue
Dc gets activated and presents antigen to T cells in lymph node
Doesn’t happen all in same place or time
What does entry of T cell into lymph node require
Activated of adhesion moelcuels and chemokines
Describe adhesion moelcuels involved in T cell entry into lymph node
Selectins=binding —> allow for rolling
Integrity = binding causes tight binding and lymphocyte to migrate= rolling stops
Describe chemokiens involves in T cell entry into lymph node
Chemokine binding chemokine receptor = ccl19 and ccl21 binds to ccr7 (chemokine receptor) on lymphocytes = leads to activation of integrins = changes conf
How do t cels enter lymph node
High endothelial venules
What are involved in leukocyte homing
Selectins
Light attachment of Selectins on T cells to HEV results in T cell rolling along endothelial surface and targeting them to lymphoid tissue
Depends on secondary organ = diff moelcuels expressed
What do diff tissues express
HEV = lymph nodes
Mucosal epithelium = peyers patches
Also adhesion moelcuels diff
Name and describe all steps of leukocyte homing = 4 main steps
Rolling = mediated by Selectins (chemokine + receptor, L selectin on T cell, integrin on T cell)
Activation = by chemokines (intracellualr signalling = activation of integrin)
Arrest and tight binding (adhesion): mediated by integrin integration
Diapedesis = transendothelial migration into lymph node
What do T cells do once in lymph node
T cells scan for antigen
Sample antigens
What do dcs do in lymph node
Can secrete chemokines to attract T cells to them
Describe what fibroblastic reticular cells do
Provide roadways for naive T cells =
Secrete ccl19 and ccl21 chemokiens = attract T cells and dcs to lymph node
What happens once T cell interacts with ag
Naive T cells arrest movements after engaging in ag:mhc
Stops moving
Slow down movement through lymph node
Describe kinetics of T cells and dc interaction
Kinetics = how long it lasts
Kinetics of early encounters depends on quality, quantity, availability of ag and activation state of a dc = if not lock and key Match, if dc will die soon, many diff condition s
What is immunological synapse
T cells become involved in commmited long term (8+ hrs) relationships with dendritic cells = immunological synapse
Is immunological synapse just between T cells and dcs
No
Between any 2 cells
Describe timing of events of T cells
Dc can be surveyed by more than 5000 T cells per hour, many cells, one match = takes time
T cells can spend 1-24 hrs circulating and looking for antigen
T cells can experience proliferation and differentiation over following 4 days
Describe immune system dynamics
Balancing generation in primary lymphoid organs with activation, proliferation and differentiation in secondary lymphoid organs
Describe immune system dynamics - deals with
Microinury, tissue repair and microbiota = other things we have to deal with
Describe immune system dynamics - overlap
Many events happening in parallel
Not linear story
Overlap over time
Can change locations and influence each other
Describe immune system dynamics = Specific stages and steps
Innate = production of cytokines = 1-5 days after infection, nk cell mediated killing of infected cells = 1-10+ days
T cell mediated killing of infected cells = 2-10+
Then down reg
What is titer
Virus titer = amount of virus
What are T cells
Types of lymphocytes
Where do T cells arise
In thymus from bone marrow progenitors
