4.3 Cells N Tissues Adapt Immunity Flashcards
All blood cells are derived from?
bone marrow stem cells
bone marrow stem cells undergo what processes to become mature cell lineages?
activation
proliferation
differentiation
Specific cytokines are required for?
- activation
- proliferation
- differentiation
- development of T lymphocytes
- other cytokines for B lymphocytes
The Immune system is divided into _____ and ______ lymphoid structures
primary and secondary
Primary lymphoid organs are sites where lymphocytes? Ex
develop without the presence of antigen, (develop, mature and replace old with new)
Ex: Bone marrow and thymus
Secondary lymphoid organs are sites where lymphocytes? Ex?
respond and develop further in response to antigen
Ex: Lymph nodes and spleen
When cells leave the primary lymphoid
organs they are mature but?
naive
What does it mean to be a ‘naive’ immune cell?
have never encountered antigen
When cells develop and oftentimes leave the secondary lymphoid organs they are considered?
effector or memory cells
what is the thymus?
- a lymphoepithelial primary lymphoid organ
- found underneath the sternum positioned above the heart
- composed of T lymphocyte lineage cells, epithelial cells, and macrophage lineage cells
- site of developement and leasning self from non-self
Thymus is a primary lymphoid structure for development of?
mature T cells
What is the site that pre-T cells from the bone marrow migrate
thymus
Explain thymus cortex, medulla and capsule?
1) Cortex contain immature pre-T cells (a lot of them)
2) Medulla contains mature T cells (learning place for self and non-self and storage)
3) Capsule= outermost layer
the medulla of the thymus acts as?
1) learning place for self and non-self
2) storage place for t-cells
In the Cortex all preT cells
express TCR, CD3, CD4, and CD8 at the cell membrane
PreT cells that are incapable of reactivity to Self MHC on thymic epithelial cells?
will die through apoptosis
apoptosis
a form of programmed
cell death
All pre T cells capable of reactivity to self MHC on thymic epithelial cells do what?
1) survive
2) proliferate
3) move on for potential future maturation
What are CDs?
cluster of differentiation
*CDs are molecules on the surface of the cell
B cells death is all dependent on?
MHC
In the Medulla, all T cells express?
TCR, CD3, CD4, or CD8- aka single positive (SP) T cells
T cells near the medulla that are strongly reactive (high affinity) Self MHC on thymic epithelial or dendritic cells will?
die through apoptosis
T cells in the medulla that are capable of weak (low/intermediate) reactivity to self MHC will?
1) survive
2) proliferate
3) complete maturation,
4) eventually exit to general circulation
Where are death domains found?
cytoplasm of cell
In order for apoptosis to happen, you must have?
1) interaction with TCR
2) FasL (a ligand) interact with Fas on cell
the ligation of FasL and Fas causes
Fas to trimerise which ACTIVATED the death domain in Fas (which then interacts with the death domain in FADD)
Procaspase binds to? This does what
binds to FADD,which creates caspase 3 which ULTIMATELY leads to apoptosis of the Fas-expressing cell
death domains initiate the development of?
caspase 3
caspase 3 is?
a key element that leads to an event for DNA fragmentation for programmed cell death
is the medulla or cortex of thymus darker?
cortex
the medulla has a lot of?
*responsible for?
cell death
*responsible for adaptive immunity in long run
Cells stick around for how long in medulla before they die and are replaced?
21 days
T cells-site of maturation is in the?
thymus
two major T cell subsets are?
CD4+ and CD8+
What are the 5 subsets of CD4+ are
- T helper 1 (Th1)
- T helper 2 (Th2)
- T helper 17 (Th17)
- T follicular helper (Tfh)
- T regulatory (Treg)
