Antigen presentation Flashcards
What cells are professional antigen presenting cells (APCs)?
dendritic cells
macrophages
B cells
How to APCs function to present antigens?
conversion of protein antigens into peptides (antigen processing)
provide stimulus to T cells (co-stimulation)
Once internalized, material is localized in vesicles called:
endosomes
How are peptides transported from the cytosol to the ER?
transporter associated with antigen presentation (TAP)
Describe T-cell receptors (TCRs)
surface molecule found on T cells
recognizes antigens presented in the correct MHC context
What are the two types of TCRs?
alpha/beta TCR: found on T cells in lymphoid tissues (MHC dependent)
gamma/delta TCR: found on T cells on mucosal surfaces (MHC independent)
What are TCR closely associated with?
CD3 complex (allows surface expression of the TCR)
What kind of antigens do TCRs recognize?
most only recognize peptides
What is self MHC restriction?
T-cells only recognize foreign peptides when they are bound to the MHC molecules of the same individual
Do B cell receptors (BCRs) react to MHC molecules?
no
What kind of molecules do BCRs recognize?
peptide, proteins, nucleic acids, polysaccharides, lipids
What is required for full T cell activation?
co-stimulatory signals
What is clonal anergy?
when co-stimulation of the T cell fails to occur and the cell becomes unresponsive
