L15 T cells Flashcards
what happens at sites of infection and inflammation in tissue
Dendritic cells take up antigen and present it on MHC
where do DC go after being at a site of infection
move to the lymph node
where do the naïve T cells come from (before entering and circulating the lymph node)
high endothelial venules (HEV)
what happens between the naïve T cells and Dc in the lymph node
the T cells scan the DC for peptides present on MHC
what must a T cell have in order to be activated by a DC
the right receptor to recognise the peptide present on MHC
names of activated T cells
CD4 helper cells
CD8 helper cells
what do the cytokines produced by T cells do?
make macrophages more bactericidal
example of a cytokine T cells can produce
IFN- gamma
what do CD4 helper cells do
activate B cells
produce cytokines
What do CD8 T cells do after being exposed to cytokines released by CD4
become cytotoxic by producing perforin and granzyme (cell-killing enzymes)
what part of both T and B cell antigen receptors interact with the peptides expressed on MHC
variable regions
why is it important for antigen receptors to have variable regions
so that they bind a range of peptides
what is a CAR T cell
chimeric antigen receptor
-an artificial receptor that recognises cancer cell antigens and triggers the T cell to produce cancer antigens
what do naive T cells form from
stem cells
what do the naive T cells (stem cells) do before entering the thymus
circulate the blood
where are T cells educated
thymus
what happens to T cells once in the thymus
stimulated to undergo rearrangement of the genes that code for the T cell receptors (mean receptors can be expressed)
what is clonal expansion
when a T cell comes into contact with an antigen
-T cell divides like crazy
what happens to the other T cell with different antigen receptors
no clonal expansion
-just stays silent
what kind of cells in the thymus kill off unwanted T cells
nurse cells (specialised dc)
what are developing thymocytes
very immature T cells
what happens to the thymocytes while in the thymus
passed over thymic stroma which expresses self-peptide on MHC I and II
Ability to bind to self MHC is tested
why is the thymus so useful when testing immature T cells
it produces a wide range of antigens found throughout the body
what happens to T cells that don’t elicit a response to MHC with self-peptide
it is considered a useless T cell
death by neglect
left to die,
