T Cell Development

Question 1

T cells differ from B cells by expressing
a. antigen receptor of only one idiotype.
b. antigen receptor of only one isotype.
c. RAG-1 and RAG-2 during somatic recombination.
d. a surrogate chain before somatic recombination of the second receptor chain is complete.
e. signal transduction molecules with their antigen receptor.

Answer 1

b. antigen receptor of only one isotype.

Question 2

The step that commits a cell to becoming a T cell is
a. expression of CD4 and CD8.
b. expression of CD3.
c. migration to the thymus.
d. somatic recombination of b chain.
e. somatic recombination of a chain.

Answer 2

d. somatic recombination of b chain.

Question 3

The thymic equivalent of the bone marrow stromal cells are the thymic
a. dendritic cells.
b. epithelial cells.
c. hormones.
d. macrophages.
e. thymocytes.

Answer 3

b. epithelial cells.

Question 4

Of the cells that enter the thymus, ____% become mature naive T cells.
a. 100
b. 75
c. 50
d. 33
e. 3

Answer 4

e. 3

Question 5

CD25 is
a. a CAM.
b. a co-receptor for TCR.
c. part of the receptor for IL-2.
d. a signal for positive selection.
e. a signal transduction molecule for TCR.

Answer 5

c. part of the receptor for IL-2.

Question 6

Double positive T cells express
a. both ab and gd TCR.
b. both CD3 and CD4.
c. both CD3 and CD8.
d. both CD4 and CD8.
e. TCR of more than one antigen specificity.

Answer 6

d. both CD4 and CD8.

Question 7

A developing T cell has more chances to productively rearrange b chain than a developing B cell has for H chain because
a. if T cells fail to rearrange b, they can rearrange g chain.
b. there are many more Vb than VH segments.
c. T cells have four alleles of each set of b gene segments, while B cells have only two alleles of each set of H chain segments.
d. there are two sets of D, J, and C b loci so that if rearrangement at the first locus fails, rearrangement can still occur at the second.
e. a developing T cell and developing B cell have exactly the same opportunities for productive rearrangements.

Answer 7

d. there are two sets of D, J, and C b loci so that if rearrangement at the first locus fails, rearrangement can still occur at the second.

Question 8

The surrogate light chain that is expressed with newly rearranged b chain
a. binds self MHC.
b. can signal the T cell without CD3.
c. is CD44.
d. is unique for each developing T cell.
e. is pTa chain.

Answer 8

e. is pTa chain.

Question 9

a chains are rearranged
a. after the T cell binds self antigen.
b. before g chains.
c. before T cells become CD3+.
d. in double negative T cells.
e. in double positive T cells.

Answer 9

e. in double positive T cells.

Question 10

Because individual T cells can rearrange more than one a chain, each cell
a. can bind multiple antigens.
b. can bind both Class I and Class II MHC.
c. can participate in both cellular and humoral immunity.
d. is not allelically excluded for a chain.
e. is not isotypically excluded for a chain

Answer 10

d. is not allelically excluded for a chain.

Question 11

Cells that have just successfully expressed both a and b chains
a. are called single positive thymocytes because they have a single specificity of TCR on each cell.
b. are all committed to becoming either Th or Tc.
c. divide rapidly before undergoing positive selection.
d. have lower amounts of membrane TCR than mature T cells.
e. have only ab receptors, while mature T cells express ab and gd receptors.

Answer 11

d. have lower amounts of membrane TCR than mature T cells.

Question 12

Single positive T cells
a. are either mature Th or mature Tc cells.
b. are found only in the thymus.
c. are ready to undergo positive selection.
d. divide rapidly before leaving the thymus.
e. undergo apoptosis if they leave the thymus and encounter foreign antigen.

Answer 12

a. are either mature Th or mature Tc cells.

Question 13

Most of our T cells are produced when we are
a. asleep.
b. less than 12 years old.
c. between 12 and 22 years old.
d. between 22 and 42 years old.
e. making a cellular response.

Answer 13

b. less than 12 years old.

Question 14

Nude mice have no
a. B cells.
b. clothes.
c. RAG-1.
d. skin.
e. thymic stroma.

Answer 14

e. thymic stroma.

Question 15

Nude mice would be unable to protect themselves from infection using
a. antibody.
b. antigen-specific cytotoxicity.
c. complement.
d. inflammation.
e. natural killer cells.

Answer 15

b. antigen-specific cytotoxicity.

Question 16

To give SCID mice a normal immune system, one would have to
a. inject antibody.
b. infuse lymphoid progenitors.
c. infuse mature T cells.
d. transplant a thymus.
e. None of the above would restore a functional immune system to a SCID mouse.

Answer 16

b. infuse lymphoid progenitors.

Question 17

The term “MHC restriction” refers to the
a. ability of MHC genes to regulate TCR rearrangement.
b. inheritance of a limited number of MHC antigens.
c. problems associated with allograft rejection.
d. requirement for antigen to be recognized in association with MHC molecules.
e. requirement for MHC molecules in order to reject grafts

Answer 17

d. requirement for antigen to be recognized in association with MHC molecules.

Question 18

T cells from an MHCaxb F1 mouse
a. all recognize antigen presented only on MHCa.
b. all recognize antigen presented only on MHCb.
c. each recognize antigen on both MHCa and MHCb.
d. each recognize antigen on either MHCa or MHCb.
e. fail to recognize antigen on any MHC except MHCaxb.

Answer 18

d. each recognize antigen on either MHCa or MHCb.

Question 19

A radiation chimera made by giving bone marrow cells from an MHCaxb mouse to an irradiated MHCa mouse produces T cells that
a. are positively selected on MHCaxb cells in the thymus.
b. can only see foreign antigen presented on MHCa APC.
c. can only see foreign antigen presented on MHCaxb APC.
d. will reject MHCa skin grafts.
e. will reject MHCb skin grafts.

Answer 19

b. can only see foreign antigen presented on MHCa APC.

Question 20

Positive selection for the production of HLA A7-restricted CD8+ T cells requires all of the following EXCEPT
a. expression of CD8 that binds the invariant part of HLA-A7.
b. expression of foreign peptide on HLA- A7.
c. expression of HLA -A7 on thymic epithelial cells.
d. rearrangement of TCR V gene segments that bind HLA -A7.
e. TAP-1 and TAP-2.

Answer 20

b. expression of foreign peptide on HLA- A7.

Question 21

Mice which were deficient in H-2M and presented CLIP on all their class II MHC molecules
a. developed autoimmunity.
b. failed to produce any CD4+ T cells.
c. failed to produce any CD8+ T cells.
d. produced CD4+ T cells that could only recognize CLIP presented on syngeneic MHC of normal mice.
e. produced CD4+ T cells that could recognize self peptides presented on syngeneic MHC of normal mice.

Answer 21

e. produced CD4+ T cells that could recognize self peptides presented on syngeneic MHC of normal mice.

Question 22

Which of the following is NOT associated with negative selection?
a. Apoptosis of thymocytes.
b. Bone-marrow derived APC.
c. Recognition of self-MHC molecules.
d. Recognition of foreign antigen.
e. Self tolerance.

Answer 22

d. Recognition of foreign antigen.

Question 23

Double positive T cells with a transgenic TCR specific for H-Y (male) antigen on self Class I MHC
a. would develop normally because H-Y is a membrane molecule and its peptides would not be presented on Class I.
b. would develop into both CD4+ T cells and CD8+ T cells in female mice but would not develop into mature T cells in male mice.
c. would develop into CD8+ T cells in female mice but would not develop into mature T cells in male mice.
d. would develop into CD8+ T cells in both female and male mice.
e. None of the above is true.

Answer 23

c. would develop into CD8+ T cells in female mice but would not develop into mature T cells in male mice.

Question 24

Expression of endogenous MMTV superantigen during T cell development
a. has no effect on because MMTV is not a self antigen.
b. negatively selects T cells with the Vb regions that bind superantigen.
c. positively selects T cells with the Vb regions that do not bind superantigen.
d. results in mice that have very strong reactivity against MMTV.
e. results in production of T cells with normal TCR diversity.

Answer 24

b. negatively selects T cells with the Vb regions that bind superantigen.

Question 25

Positive and negative selection of T cells
a. involve different MHC molecules.
b. involve different peptides.
c. must involve signals that differ either in amount or in type.
d. occur in the same thymus microenvironment.
e. result in T cells which can never recognize self antigen.

Answer 25

c. must involve signals that differ either in amount or in type.

Question 26

The maximum number of Class I and Class II MHC genes we have is probably NOT influenced by
a. the maximum number of MHC genes that can be carried in the DNA.
b. the maximum number of MHC molecules that can be expressed on the cell surface.
c. the maximum number of peptide-MHC complexes that will not result in excessive negative selection of T cells.
d. the minimum number of peptide-MHC complexes that must be bound by a T cell to send a strong enough signal to activate the T cell.
e. the minimum number of pathogen peptides that must be recognized for a person to survive.

Answer 26

a. the maximum number of MHC genes that can be carried in the DNA.

Question 27

A monoclonal T cell tumor which developed from a normal T cell would NOT express the normal T cell’s
a. cell surface markers.
b. division rate.
c. organ location.
d. TCR gene rearrangement.
e. All of the above would resemble the normal parent cell.

Answer 27

b. division rate.

Question 28

Most of the cells that enter the thymus
a. become MHC-restricted ab TCR cells.
b. become MHC-restricted gd TCR cells.
c. become monoclonal T cell tumors at various stages of development.
d. die because they cannot make a self-MHC binding TCR.
e. die because they bind self peptide.

Answer 28

d. die because they cannot make a self-MHC binding TCR.

Question 29

gd T cells
a. are made before ab T cells during fetal development.
b. are more diverse than ab T cells.
c. are precursors of ab T cells.
d. outnumber ab T cells 19:1 in the spleen.
e. probably bind common pathogen peptides on Class II MHC.

Answer 29

a. are made before ab T cells during fetal development.

Question 30

The step that commits a cell to becoming a gd T cell is
a. development outside the thymus.
b. expression of more gd than ab receptors on its surface.
c. migration out of the thymus to the skin.
d. somatic recombination of d chain before a chain.
e. somatic recombination of g chain before b chain.

Answer 30

d. somatic recombination of d chain before a chain.