Lymphoctye activation: T cell Flashcards
What is the percentage break down of T lymphoctyes that circulate and stay in one place
50% vs 50%
What are the three type of mature T lymphoctes
naive, effector, memory
What is the function of naive lymphocytes, where are they located
antigen recognition, reside in lymph nodes
What is the function of effector T lymphocytes
perform functions required to eliminate microbes in periphery
What is the function of memory T lymphocytes
functionally silent cells but mount rapid responses to antigen challenge (secondary response)
What is a key difference in T cells and B cells
T cells require antigen presentation by other cells vs B cells that recognize whole antigens on their own; antigen peptides vs antigen parts
What is the function of helper T cells, what protein causes activation
Cytokine production that leads to T cell differentiation, B cell growth, macrophage activation, MHC 2 restricted activation
What is the function of cytotoxic T cells, what protein cause activation
Lysis of virus and tumor infected cells, MHC 1 restricted activation
Which cells present MHC 1 protein, MHC 2
all nucleated cells, antigen presenting cells
What is the difference in antigen that would determine MHC class
MHC 1 -> endogenous protein antigen catabolized in the cytoplasm MHC 2-> exogenous protien antigen catabolized in acid compartment
What are the functions of antigen presenting Cells
process and present antigen to T-lymphocytes, provide secondary stimuli to the T cell required for achievement of full T cell response
T/F: APCs can express MHC 1 and MHC 2
True
What is the most key feature of dendritic cells. what are other important features
Most efficient in initiating adaptive immune response, travel from periphery (site of infection) to lymph nodes to activate naive T cells/express high levels of costimulatory and adhesion molecules
What is the most key feature of macrophages, what are other important features
provide continuous stimuli to keep T cells going at the periphery, have low levels of MHC 2 at first but cytokine stimulation will lead to higher levels of MHC 2
Where does a large number of APC interactions with Naive T cells occur
Lymph nodes
What part of the T cell interacts with the APC
TCR
T/F: It is sufficient and necessary to have and interaction between the TCR and MHC 2 of APCs
False: it is necessary but not sufficient to propagate a signal
What are the components needed for full T cell activation
Co-receptor (CD4 or CD8), costimulatory pairs, adhesion molecules
What are costimulatory pairs, are they essential for activation of naive T cells
clustered intracellular signaling molecules around the TCR allowing activation signal to dispatched to the nucleus, yes
What are the two most important costimulatory pairs (for this class) where cell types are they located on
B7 (infected cells)/CD28 (T cells). CD40L (T cells)/CD40 (APCs)
T/F: Effector and memory T cells require less co-stimulation
True
What are processes that occur due to B7/CD28 binding
mobilize kinases and other signaling proteins around TCR, increase half life of cytokine mRNA molecules ( leads to 100x more cytokines produced), increase T-Cell proliferation, prevent apoptosis
What are processes that occur due to CD40/CD40L binding
On APC: promote up regulation of MHC and other costimulatory molecules/increase longevity of dendritic cells by increasing production of IL-12, For B cell: Promotes B cell proliferation/promote Ig class switching
What is the function of adhesion molecules
form an outer ring, stabilizing the T cell-APC contact and assist in migration of T cell to sites of inflammation and infection
