MFM II - Cell-Mediated Immunity I: Activation of T Cells

what can induce maturation of the dendritic cells?

cytokines such as TNF-α and PRR ligation

how do immature T cells access lymph nodes?

through high endothelial venules

what are the 3 signals required for T Cell activation?

1. interaction with antigen and MHC (adhesion molecules stabilize the interaction of TCR with MHC-peptide complex)

2. Co-stimulation (interaction with co-stimulatory molecules)

3. Cytokines (IL-2, polarizing cytokines (chemokines))

what describes signal 1 for T cell activation?

Engagement of the TCR by MHC-peptide complex

what describes signal 2 for T cell activation?

B7 (dendritic or APC cell co-stimulatory molecule) binds with CD28 (T cell co-stimulatory receptor)

B7 is only expressed on what cells?

professional APC

the binding of B7 and CD28 leads to what?

production of the growth factor cytokine IL-2 and its high affinity receptor

absence of interaction between B7 and CD28 leads to what?

inactivation of T cell (anergy)

what describes signal 3 of T cell activation?

cytokines

Ag recognition activates what?

CD4/CD8 associated Lck

Lck phosphorylates what?

ITAMS

phosphorylated ITAMs recruit what?

Zap-70

Zap-20 phosphorylates what?

LAT

Phosphorylated LAT leads to what?

3 pathways

• PKC activates production of NF-κB

• Calcium ions leads to production of NFAT

• MAPK pathway leads to production of AP-1

PKC activates production of what

NF-κB

Calcium ions leads to production of what?

NFAT

MAPK pathway leads to production of what?

AP-1

proliferation and differentiation of activated naive T cells are drive by what?

IL-2

activation of T cells results in production of what?

IL-2

what roles does IL-2 play in regards to T cells?

• clonal expansion

• survival

• prepares cell for differentiation (promotes gene expression of CD40 ligand and cytokine receptors)

Memory T cells remain after what?

response resolution

memory T cells maintain what?

IL-7R expression