T cells Flashcards
where does T cell gene rearrangememt take place?
in the thymus
how do T cells move within the thymus?
T cells move from venules into the cortex, then enter the medulla prior to leaving the thymus
does negative or positive T cell selection occur first?
Positive selection occurs first and then negative selection
what are the stages of T cell progression?
Maturing T cells progress through a double negative to double positive stage to single positive stage (CD4+ or CD8+)
what supports expression of a T cell rearranged Beta chain?
Supported by an invariant pre-TCR pTalpha)
what happens if the T cell beta chain is successfully expressed?
The alpha chain then undergoes recombination
what is the order of chain rearrangment in maturing T cells?
the beta-TCR chain is arranged first and then the alpha-TCR chain
what do double positive thymocytes mature into?
CD4+ or CD8+ T cells
what confines T cell receptors?
Their ability to only recognise MHC plus peptide
What happens following thymic selection of T cells?
The T cell receptors are less variable in shape than antibody
what is a requirement of antibody?
Antibody must be able to recognise an almost infinite variety of shapes
what is CD3 comprised from?
Zeta, epsilon-gamma and epsilon-delta chains
what charge is the TCR?
T cell receptors are positively charged and so attract stuff
what mediates the association between different TCR molecules?
The charge difference in transmembrane domains
what do the TCR alpha-beta regions associate?
CD3
