CH.10: T Cell Development and Activation Flashcards
1
Q
Describe natural killer T (NKT) cells.
A
- has TCR
- respond to glycolipid antigens presented by CD1d (not MHC)
- regulate other sets of T cells and regulating conditions (autoimmunity, cancer, infection)
1
Q
What are treg cells?
A
- subset of CD4+ T cells
- inhibit actions of other sets of T cells
- inhibits responses from self and foreign antigens
2
Q
What are natural killer (NK) cells?
A
- has no TCR
- apart of innate immune defense
- kills virus-infected and tumor cells
3
Q
what does the two-signal model of CD4+ activation describe?
A
- TCR and MHC
- CD28 and B7
4
Q
Describe further differentiation of CD4+ and CD8+ T cells.
A
- when activated by antigen, they can differentiate into effector T cells (able to perform function without further activation)
- CD4+ effector cells: synthesize cytokines
- CD8+ effector cells: kill host cells infected with viruses
- some become memory cells
5
Q
DN > pre > DP > thymic selection > SP
Describe DN T cell.
A
- rearrangement of TCR begins (RAG 1, RAG2)
- decision to become alpha-beta or gamma-delta T cell
6
Q
DN > pre > DP > thymic selection > SP
Describe pre T cell.
A
- consists of beta chain, pre-T-alpha, CD3, zeta
- must express pre-TCR
7
Q
DN > pre > DP > thymic selection > SP
Describe DP T cell.
A
- alpha genes rearrange (RAG1, RAG2; deletion of delta locus)
- initiates cell proliferation and co-receptor molecules
- expresses alpha-beta TCR, CD3, zeta and co-receptors: CD4, CD8
8
Q
DN > pre > DP > thymic selection > SP
Describe thymic selection.
A
- positive selection: cells become educated to self-MHC; ensures that it will respond to antigen only when it is bound to MHC molecules it encountered in thymus
- negative selection: cells with affinity that is too low or too high for self-MHC will be eliminated
- if cells survive, it will either become a mature CD4+ OR CD8+ T cell
9
Q
DN > pre > DP > thymic selection > SP
Describe SP T cell.
A
- CD4+ and CD8+ T cells that survived thymic selection
- leave thymus as naive T cells and circulate throughout body
10
Q
What are T cell co-receptors (CD4, CD8)?
A
- act as specific adhesion molecules; tightens binding of T cell to host cell (MHC)
- signal transduction molecules
- HIV-1 binds to CD4; results in AIDS
11
Q
Describe the TCR complex.
A
- consists of TCR, CD3, zeta
- CD3 and zeta are signal transduction molecules
12
Q
Describe antigen-specific TCR.
A
- does not change during response to antigen
- interacts with peptides bound to MHC molecule on surface of host cell
13
Q
What genes code for TCRs?
A
- alpha and gamma chains: V, J
- beta and delta chains: V, D, J
