IMIN 200 Lecture 8

Question 1

Lymphoctyes begin as…

Answer 1

pluripotent stem cells in BM

Question 2

Stem cells can develop into

Answer 2

IgM+ B cells

T cell precursors

Question 3

What generates a naive T cell with a unique TCR

Answer 3

somatic recombination in thymus

Question 4

chains in T cells

Answer 4

made of alpha and beta

Question 5

role of recombinase

Answer 5

rearrange V and J gene segments to form alpha chain

Question 6

what if recombinase is productive+what is the effect of this

HINT: what does this do for the TCR

Answer 6

shut off at other end of alpha chain locus+recombinase is shut off at other alpha chain locus
->prevents cells from expressing more than one TCR

Question 7

Explain allelic exclusion

Answer 7

each individual inherits maternal and paternal alpha chains–>exclusion ensures that single B/T lymphocyte responds only to a single BCR or TCR (antigen) and is specific

Question 8

Where does selection occur

Answer 8

Thymus

Question 9

Where do the T cells find the antigen

Answer 9

migrate to periphery to look for antigen on MHC class I or II

Question 10

How does a TCR differ from antibody (think chains)

Answer 10

has alpha and beta chains each with a variable (V) and constant (C) region

Question 11

The C-terminus

Answer 11

does not have effector functions, is needed for signalling

Question 12

Antigenic peptide is bound in

Answer 12

peptide binding groove formed by alpha 1 and 2 domains

Question 13

What do CD4 and CD8 cells interact with?

Answer 13

NOT with antigenic peptide, only with invariant residues