Tolerance Induction & MHC Restriction

Question 1

hormones produced in thymus

Answer 1

thymulin
thymosin alpha-1
thymopoietin

Question 2

T cells must be restricted to recognize self so that attention of T cells will be focused on:

Answer 2

MHC-peptide complexes

Question 3

nude T cells are resistant to _______ because express little or NO Fas protein, but express HIGH levels of ______

Answer 3

apoptosis

Bcl-2

Question 4

no ______ lymphatics in THYMUS

Answer 4

afferent

Question 5

T cells develop into ____ cells in thymus

Answer 5

double positive (DP) cells

Question 6

DP cells contain ____ & _____ receptor molecules

are MOST common lymphocyte in thymus

Answer 6

CD4

CD8

Question 7

DP cells are sensitive to death; must pass 2 tests:

Answer 7

1 MHC recognition

2 Tolerance to self

Question 8

CD44 is receptor for ______ and is associated with THYMOCYTE migration events- considered a MARKER

Answer 8

hyaluronic acid

Question 9

CD24 is a chain of ______ receptor when express with beta and gamma chain the receptor acquire _____ affinity for IL-2 favoring IL-2 thymocyte proliferation

Answer 9

IL-2

high

Question 10

MHC restriction is _______ selection

Answer 10

positive

Question 11

Tolerance to self is _____ selection

Answer 11

negative

Question 12

process of testing T cells for MHC selection is called _______; ________ check to see that T cells have receptors TCR that recognize one of the “self MHC” molecules expressed

Answer 12

positive selection

cortical epithelial cells

Question 13

if CEC recognize “self MHC” molecules –> T cell ______

If CEC doesn’t “ “ —> T cell ____

Answer 13

lives

dies

Question 14

positive selection is about _____ on antigen presented by MHC and takes place in the _____

Answer 14

FOCUSING

thymus

Question 15

Some T cells start to rearrange the gene segments encoding alpha or beta chains of TCR, if successful, they express LOW levels of ______, ____ and _____ and HIGH levels of _____

Answer 15

TCR
CD3
Bcl-2
Fas

Question 16

CEC that display peptides on MHC I molecules are _____ ; MHC II molecules are ______

Answer 16

within the cell

samples from the area

Question 17

two types of cells that give the negative selection test

Answer 17

thymic dendritic cells

medullary thyme epithelial cells

Question 18

after positive selection, T cells choose either ___ or ____ and are now called _______

Answer 18

CD4
CD8
single positive cell

Question 19

in negative selection, ______ cells check if T cells recognize any SELF peptides displayed by MHC molecules on cells surface

• if they do recognize, cells ______
• if they do NOT recognize, cells _____

Answer 19

thymic dendritic cells
die
live

Question 20

cells that express tissue specific proteins that are unique to different tissues/organs in body

• check to see if cells are TOLERANT
• if tolerant, cells _____
• if NOT tolerant, cells _____

Answer 20

medullary thymic epithelial cells
live
die

Question 21

medullary thymic epithelial cells ensure that we create T cells that do NOT recognize ________ that thymic dendritic cells missed

Answer 21

tissue-specific proteins

Question 22

medullary thymic epithelial cells practice ______, and regularly enclose portions of their cytoplasm within a membrane

Answer 22

autophagy

Question 23

testing takes about ______, and the pass rate is about ______, failing the test leads to ______

Answer 23

2 weeks
1 in 30
apoptosis