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Chpt 14


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How many signals are required for activation of

-Naieve Th and Tc cells

-Effector T cells (TH1, TH2, CTLs)
Naieve require 3 signals

Effectors require only signal 1 (Ag interaction) and secrete enough of their own IL-2 to prolif/different by themselves.
Role of Th1 cells in activating Naieve CTL-P
secrete IL-2 for diff/prolif of CTL
upregulate B7 on APC for enhanced co-stim signal and activation of CTL
Fill in the blanks:CTL-P activCTL-P CTL

IL-2R expression
IL-2 expression
Effector function
CTL-P activated CTL-P CTL

- + +
- +/- +/-
- - +
- - +
Which signal is not required for activation of effector Tcells?
Co-stim of B7/CD28
Characteristics that differentiate Naieve from Effector Tcells
-Necessity of Co-stim signal for activ.
-Constitutive vs. induced Cell adhesion molecules
-Cell trafficking patterns - what are they?
-Synthesis of molecules
Cell trafficking patterns of
-Naieve tcells
-Effector t-cells
Naieve: 2ndary lymphoid HEV

Effector: Tertiary lymph tissues, inflammatory sites- - all over
Molecules synthesized by
-Effector CTLs
NAieve: nothing

Effector: CAMs, cytotoxic granules
What component of CTLs mediates target cell damage?
Perforin, Granzymes
How does granzyme-B get from CTLs to target cells?
-Perforin makes pores

-Both are endocytosed by Target and then Perforin makes pores for granzyme-b to get out of granule inside target.
what two pathways mediate apoptosis inside target cells
FAS pathway

Granzyme/Perforin pathway
what do both pathways activate for apoptosis?
caspase pathway
What is the first line of defense against viral infection? why?
Natural Killer cells

Because they are induced by release of TNF-alpha and beta immediately following infection, and their activity climaxes at about day 3, during activation/proliferation of p-CTLs
which cells mediate cytotoxity via ADCC?
NK, neutrophils, eosinophils, macrophages.
What is the outcome of ADCC for
NK cells
NK cells will cause apoptosis because they induce the caspase pathway with Granzymes/FAS

Neutro/Eosino/Macroph produce lytic enzymes that induce lysis nonspecifically

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