Antigen Presentation Flashcards
Where does protein processing and antigen occur?
APCs and every eukaryotic cell in the body
Produce self antigens and nonself anitgens on MHC class I molecules
What do dendritic cells present their peptides to?
Both CD4 helper cells to initiate helper cytokine release and CD8 cells for activation into killer cells
What do macrophages present antigen to?
Initiate helper T cell cytokine release
Activates macrophages
What do B cells present their antigens to?
Present peptide antigens to CD4 helper T cells for cytokine release
Facilitates development of T dependent antibody release and antibody class switching
What two divisions make up adaptive immunity?
Cell Mediated Immunity and Humoral immunity
What are dendritic cells?
Heterogeneous population of cells which have immunostimulatory capacity
Take different names depending on location
Describe the function of dendritic cells
Process and present antigen on class I or class II proteins
Undergo maturation process if TLR is engaged
Migrate to draining lymph nodes
Present antigen to naive T cells (CD4 and CD8)
What occurs in dendritic cells if the TLR is engaged?
Upregulate Class I and Class II proteins
Upregulate costimulatory molecules (CD80/CD86/CD40)
Where do DCs and antigens enter the lymph node?
Afferent lymphatic vessels
Where do naive T and B cells enter the lymph node?
Postcapillary HEV
How do microbial products enhance the APC function of macrophages and dendritic cells?
PRRs stimulated
CD80/86 expression induced
Signal 2 can be delivered
T cells can be activated
What is antigen processing?
Intracellular degradation of protein antigens into peptides (proteosome)
What does the mechanism of antigen processing depend on?
Location of the protein and type of APC
How are intracellular antigens processed?
Class I molecules bind and present peptides derived from cytoplasmic sources of antigen
How are antigens processed in B cells?
Surface immunoglobulin captures extracellular antigen
The antigen is processed and presented via MHC Class II molecules
What is the role of coreceptors CD4 and CD8 on T cells?
The ensure that T cell subsets bind to the proper class of MHC
What signals are required for antigen-specific activation of naive T cells?
Both signal 1 - comes from TCR
And signal 2 - comes from CD28/B7
However this does not lead directly to T cell proliferation
What are the three signals that APCs deliver to naive T cells?
Activation - MHC-TCR
Survival - B7/CD28
Differentiation - cytokines
What does the activation of naive antigen-specific T cells lead to?
Synthesis of IL-2 and high affinity IL-2 receptors
What three transcription factors are formed as a result of TCR signaling?
NFAT
NFkB
AP-1
