Lecture 4 - B and T cell development Flashcards
in B cell development, in which reaction does most cell division occur?
germinal centre reaction
the germinal centre reaction is related to what type of immune response? primary or secondary?
secondary
where do B cells originate from?
haematopoietic stem cells in the bone marrow
which transcription factor do B cells express?
PAX 5
what is the correct order of B cell development?
a) L chains rearrange
b) L chain expression stopped
c) H chain rearranges, expressed with surrogate L chain
d) pre-BCR turns off RAG 1 and 2
e) cell division
f) RAG 1 and 2 turned on again
c, d, e, b, f, a
immature B cells express which Ig only?
IgM
immature B cells that bind multivalent self antigen undergo one of two processes. what are they?
either clonal deletion or receptor editing
immature B cells that bind soluble self antigen become what?
anergic
True or false: B cells undergo positive and negative selection?
false, this is what T cells undergo
if cells don’t express PAX5, they leave the bone marrow and go to the…… to become ……cells
thymus
T cells
gamma delta T cell receptors are found in which tissues?
epithelial
alpha beta T cell receptors bind with self…. molecules in the thymus and undergo ……. selection
MHC
positive
Regarding T cell development, thymocytes, in the thymus, express which receptor?
what markers do they acquire? (hint: what are the types of T cell)
t cell receptor
they acquire CD3, CD4 or CD8 markers
the lobules of the thymus are divided into what two things?
cortex and medulla
where are pro-thymocytes found within the thymus? which section?
cortex
which genes are rearranged first in T cells? which are rearranged second?
(TCR beta or TCR alpha)
TCR beta first
TCR alpha second
the CD3 TCR complex has which 4 chains, one being a dimer?
which chain is the dimer?
gamma, delta, epsilon, zeta
zeta chain is the dimer
where does the CD3 TCR complex submit the signal to within the T cell, following MHC recognition?
to the nucleus
which CD markers do gamma-delta T cells NOT express?
CD4, CD8
where in the thymus, does positive selection occur?
in cortex
where do positively selected T cells move to in the thymus?
medulla
what do positively selected T cells recognise?
self-MHC molecules
what happens to T cells which can’t recognise self MHC molecules?
die/apoptosis
where does negative selection of T cells occur in the thymus?
medulla, following positive selection
in the negative selection of T cells, T cells which recognise MHC on which cells with what affinity are clonally deleted?
on thymic dendritic cells
with HIGHEST affinity
in T cell development, the production of T cells with which property is the goal?
the production of T cells with low affinity for self peptide/self MHC
what could T cells with low affinity for self MHC induce in a human individual?
autoimmunity
