Adaptive Immunity III

Question 1

In addition to the MHC and TCR binding between dendritic cells and naive T cells, what other binding signals activation of T cells?

Answer 1

The B7-1 and B7-2 molecules on the dendritic cells bind to the CD28 on the T cells.

Question 2

What are the CDRs of TCRs and BCRs and what characteristics do they have?

Answer 2

CDR1= binds to MHC and peptide
CDR2=binds to MHC
CDR3=binds to peptide and most variable.

Question 3

Which T cells have subsets?

Answer 3

CD4+ T helper cells.

Question 4

What do TH1 subsets react to?

Answer 4

Viruses and intracellular Bacteria.

Question 5

What do TH17 subsets react to?

Answer 5

Extracellular Bacteria and fungi.

Question 6

What do TH2 subsets react to?

Answer 6

Parsitic worms and bloodsucking insects.

Question 7

What do most CD8 T cells differentiate into? What do these cells produce?

Answer 7

Cytotoxic effector T cells that produce IFN-y, TNF.

Question 8

What do IFN-y do?

Answer 8

Upregulates MHC class I.

Question 9

What are the cytotoxic mechanisms of CD8 T cells (Perforin, Granzymes, Fas)?

Answer 9

T cells releases Perforin. Ca++ activate assembly of perforin ,which causes a huge hole which the Granzymes can enter and induce cell death. FasL on T cells interacts with Fas on infected cells and turns on suicide switch.