Question 1

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED)is caused by a defect in

Accepted Answer

A) cathepsin L 
B) a transcription factor that regulates tissue-specific gene expression in the thymus 
C) the production of regulatory CD4 T cells 
D) FoxP3 
E) T-cell receptor gene rearrangement. 
A) cathepsin L 
B) a transcription factor that regulates tissue-specific gene expression in the thymus 
C) the production of regulatory CD4 T cells 
D) FoxP3 
E) T-cell receptor gene rearrangement. B

Question 2

Genetic deficiencies in all of the following would impair the development of a fully functional T-cell repertoire except

Accepted Answer

A) RAG-1 or RAG-2 
B) Notch1 
C) Pax-5 
D) IL-7 receptor (CD127) 
E) TAP-1 or TAP-2. 
A) RAG-1 or RAG-2 
B) Notch1 
C) Pax-5 
D) IL-7 receptor (CD127) 
E) TAP-1 or TAP-2. C

Question 3

Thymocytes that are not positively selected

Accepted Answer

A) undergo genetic reprogramming and differentiate into a different cell type 
B) are exported to the periphery,where they are phagocytosed by macrophages 
C) make up about 98% of developing thymocytes and die by apoptosis in the thymic cortex 
D) are eliminated because of their reactivity with self antigens 
E) try out different β chains to acquire reactivity with self-MHC molecules. 
A) undergo genetic reprogramming and differentiate into a different cell type 
B) are exported to the periphery,where they are phagocytosed by macrophages 
C) make up about 98% of developing thymocytes and die by apoptosis in the thymic cortex 
D) are eliminated because of their reactivity with self antigens 
E) try out different β chains to acquire reactivity with self-MHC molecules. C

Question 4

Which of the following statements is correct?

Accepted Answer

A) In adults the mature T-cell repertoire is self-renewing and long-lived and does not require a thymus for the provision of new T cells. 
B) T cells and B cells are both short-lived cells and require continual replenishment from primary lymphoid organs. 
C) The human thymus is not fully functional until age 30,at which time it begins to shrink and atrophy. 
D) In DiGeorge syndrome the bone marrow takes over the function of the thymus and produces mature peripheral T cells. 
E) None of the above statements is correct. 
A) In adults the mature T-cell repertoire is self-renewing and long-lived and does not require a thymus for the provision of new T cells. 
B) T cells and B cells are both short-lived cells and require continual replenishment from primary lymphoid organs. 
C) The human thymus is not fully functional until age 30,at which time it begins to shrink and atrophy. 
D) In DiGeorge syndrome the bone marrow takes over the function of the thymus and produces mature peripheral T cells. 
E) None of the above statements is correct.

Question 5

If a double-negative thymocyte has just completed a productive β-chain gene rearrangement,which of the following describes the immediate next step in the development of this thymocyte?

Accepted Answer

A) A pre-T-cell receptor is assembled as a superdimer. 
B) Rearrangement of γ- and δ-chain genes commences. 
C) Expression levels of RAG-1 and RAG-2 are elevated. 
D) The linked δ-chain genes are eliminated. 
E) This cell will inevitably differentiate into a committed γ:δ T cell. 
A) A pre-T-cell receptor is assembled as a superdimer. 
B) Rearrangement of γ- and δ-chain genes commences. 
C) Expression levels of RAG-1 and RAG-2 are elevated. 
D) The linked δ-chain genes are eliminated. 
E) This cell will inevitably differentiate into a committed γ:δ T cell.

Question 6

MHC class II deficiency is inherited as an autosomal recessive trait and involves a defect in the coordination of transcription factors involved in regulating the expression of all MHC class II genes (HLA-DP,HLA-DQ,and HLA-DR).
A.What is the effect of MHC class II deficiency?
B.Explain why hypogammaglobulinemia is associated with this deficiency.

Accepted Answer

A.MHC class II deficiency affects the de

Question 7

Giulia McGettigan was born full term with a malformed jaw,cleft palate,a ventricular septal defect,and hypocalcemia.Within 48 hours of birth she developed muscle tetany,convulsions,tachypnea,and a systolic murmur.A chest X-ray showed an enlarged heart and the absence of a thymic shadow.Blood tests showed severely depleted levels of CD4 and CD8 T cells; B-cell numbers were low but within normal range.Parathyroid hormone was undetectable.Fluorescence in situ hybridization of the buccal mucosa revealed a small deletion in the long arm of chromosome 22.Giulia failed to thrive and battled chronic diarrhea and opportunistic infections,including oral candidiasis and Pneumocystis jirovecii,the latter infection causing her death.Giulia most probably had which of the following immunodeficiency diseases?

Accepted Answer

A) AIDS 
B) DiGeorge syndrome 
C) bare lymphocyte syndrome 
D) chronic granulomatous disease 
E) hyper IgM syndrome. 
A) AIDS 
B) DiGeorge syndrome 
C) bare lymphocyte syndrome 
D) chronic granulomatous disease 
E) hyper IgM syndrome.

Question 8

Immediately after positive selection

Accepted Answer

A) the thymocyte reaches maturity and is exported to the periphery 
B) RAG proteins are degraded and are no longer synthesized 
C) receptor editing commences to eliminate reactivity against self antigens 
D) the developing thymocyte acquires a double-negative phenotype 
E) expression of pTα is repressed. 
A) the thymocyte reaches maturity and is exported to the periphery 
B) RAG proteins are degraded and are no longer synthesized 
C) receptor editing commences to eliminate reactivity against self antigens 
D) the developing thymocyte acquires a double-negative phenotype 
E) expression of pTα is repressed.

Question 9

In which of the following ways does the developmental pathway of α:β T cells differ from that of B cells? (Select all that apply.)

Accepted Answer

A) Their antigen receptors are derived from gene rearrangement processes. 
B) When the first chain of the antigen receptor is produced it combines with a surrogate chain. 
C) Cells bearing self-reactive antigen receptors undergo apoptosis. 
D) MHC molecules are required to facilitate progression through the developmental pathway. 
E) T cells do not rearrange their antigen-receptor genes in the bone marrow. 
A) Their antigen receptors are derived from gene rearrangement processes. 
B) When the first chain of the antigen receptor is produced it combines with a surrogate chain. 
C) Cells bearing self-reactive antigen receptors undergo apoptosis. 
D) MHC molecules are required to facilitate progression through the developmental pathway. 
E) T cells do not rearrange their antigen-receptor genes in the bone marrow.

Question 10

Match between columns
                        Premises: DiGeorge syndrome
APECED
Bare lymphocyte syndrome
IL-7 receptor deficiency
IPEX

Accepted Answer

The Answer of absence of functional AIRE and absence of is...

Question 11

Which of the following is mismatched:

Accepted Answer

A) double-negative CD3- thymocytes: cortico-medullary junction 
B) double-negative CD3- thymocytes: subcapsular zone 
C) double-positive CD3+ thymocytes: cortico-medullary junction 
D) cortical epithelial cells: subcapsular regions 
E) dendritic cells: cortico-medullary junction. 
A) double-negative CD3- thymocytes: cortico-medullary junction 
B) double-negative CD3- thymocytes: subcapsular zone 
C) double-positive CD3+ thymocytes: cortico-medullary junction 
D) cortical epithelial cells: subcapsular regions 
E) dendritic cells: cortico-medullary junction.

Question 12

A.What is Notch1?
B.Which cells express the ligand of Notch1?
C.How does the interaction between Notch1 and its ligand mediate T-cell development?

Accepted Answer

A.Notch1 is a membrane-bound receptor fo

Question 13

Which of the following statements regarding positive selection is correct?

Accepted Answer

A) All subsets of developing T cells undergo positive selection before export to the peripheral circulation. 
B) T-cell receptor editing is linked to the process of positive selection. 
C) Positive selection results in the production of T cells bearing T-cell receptors that have the capacity to interact with all allotypes of MHC class I and class II molecules,and not just those of the individual. 
D) Positive selection ensures that autoreactive T cells are rendered non-responsive. 
E) If there is a genetic defect in AIRE,then T-cell development is arrested as positive selection commences. 
A) All subsets of developing T cells undergo positive selection before export to the peripheral circulation. 
B) T-cell receptor editing is linked to the process of positive selection. 
C) Positive selection results in the production of T cells bearing T-cell receptors that have the capacity to interact with all allotypes of MHC class I and class II molecules,and not just those of the individual. 
D) Positive selection ensures that autoreactive T cells are rendered non-responsive. 
E) If there is a genetic defect in AIRE,then T-cell development is arrested as positive selection commences.

Question 14

Which of the following is the first stage of T-cell receptor gene rearrangement in α:β T cells?

Accepted Answer

A) Vα→Dα 
B) Dα →Jα 
C) Vβ→ Dβ 
D) Dβ→Jβ 
E) Vα→Jα. 
A) Vα→Dα 
B) Dα →Jα 
C) Vβ→ Dβ 
D) Dβ→Jβ 
E) Vα→Jα.

Question 15

Which of the following cell-surface glycoproteins is characteristic of stem cells,but stops being expressed when a cell has committed to the T-cell developmental pathway?

Accepted Answer

A) CD2 
B) CD3 
C) CD25 
D) CD34 
E) MHC class II. 
A) CD2 
B) CD3 
C) CD25 
D) CD34 
E) MHC class II.

Question 16

Individuals with a defective autoimmune regulator gene (AIRE)exhibit

Accepted Answer

A) DiGeorge syndrome 
B) autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECE
D)  
C) severe combined immunodeficiency (SCI
D)  
D) MHC class I deficiency 
E) MHC class II deficiency. 
A) DiGeorge syndrome 
B) autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECE
D)  
C) severe combined immunodeficiency (SCI
D)  
D) MHC class I deficiency 
E) MHC class II deficiency.

Question 17

If the process of positive selection did not occur,then

Accepted Answer

A) a condition resembling immune dysregulation,polyendocrinopathy,enteropathy,X-linked syndrome (IPEX)would develop 
B) a condition resembling autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECE
D) would develop 
C) naive T cells would be unable to undergo differentiation in secondary lymphoid tissues 
D) malignant transformation would be more likely because of the accumulation of multiple mutations 
E) only a very small percentage of circulating T lymphocytes would be able to become activated. 
A) a condition resembling immune dysregulation,polyendocrinopathy,enteropathy,X-linked syndrome (IPEX)would develop 
B) a condition resembling autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECE
D) would develop 
C) naive T cells would be unable to undergo differentiation in secondary lymphoid tissues 
D) malignant transformation would be more likely because of the accumulation of multiple mutations 
E) only a very small percentage of circulating T lymphocytes would be able to become activated.

Question 18

A.What is the role of regulatory CD4 T cells (Treg)?
B.How can Treg be distinguished from other non-regulatory CD4 T cells?

Accepted Answer

A.T_reg suppress the proliferation of naive

Question 19

Identify which of the following describes how antigen processing and presentation of self antigens by thymic epithelial cells differs from that of antigen-presenting cells in peripheral tissues.(Select all that apply.)

Accepted Answer

A) Thymic epithelium expresses MHC class I molecules but not MHC class II molecules. 
B) Thymic epithelium uses cathepsin L for proteolytic degradation of self proteins. 
C) Thymic epithelium expresses MHC class II molecules but not MHC class I molecules. 
D) Thymic epithelium uses the transcription factor AIRE to activate thymic expression of tissue-specific genes. 
E) Thymic epithelium expresses transcription repressor protein FoxP3. 
A) Thymic epithelium expresses MHC class I molecules but not MHC class II molecules. 
B) Thymic epithelium uses cathepsin L for proteolytic degradation of self proteins. 
C) Thymic epithelium expresses MHC class II molecules but not MHC class I molecules. 
D) Thymic epithelium uses the transcription factor AIRE to activate thymic expression of tissue-specific genes. 
E) Thymic epithelium expresses transcription repressor protein FoxP3.

Question 20

The T-cell receptor β-chain locus can undergo successive gene rearrangements to rescue unproductive V(D)J rearrangements.
A.What aspects of gene segment rearrangement at the TCRβ locus make this possible?
B.Can the immunoglobulin heavy-chain locus,which is also composed of V,D,and J segments,undergo successive rearrangements? If not,give the reasons for the difference.

Accepted Answer

A.Successive gene rearrangement is possi

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED)is caused by a defect in

Genetic deficiencies in all of the following would impair the development of a fully functional T-cell repertoire except

Thymocytes that are not positively selected

Which of the following statements is correct?

If a double-negative thymocyte has just completed a productive β-chain gene rearrangement,which of the following describes the immediate next step in the development of this thymocyte?

Immediately after positive selection

In which of the following ways does the developmental pathway of α:β T cells differ from that of B cells? (Select all that apply.)

Which of the following is mismatched:

A.What is Notch1? B.Which cells express the ligand of Notch1? C.How does the interaction between Notch1 and its ligand mediate T-cell development?

Which of the following statements regarding positive selection is correct?

Which of the following is the first stage of T-cell receptor gene rearrangement in α:β T cells?

Which of the following cell-surface glycoproteins is characteristic of stem cells,but stops being expressed when a cell has committed to the T-cell developmental pathway?

Individuals with a defective autoimmune regulator gene (AIRE)exhibit

If the process of positive selection did not occur,then

A.What is the role of regulatory CD4 T cells (T_reg)? B.How can T_reg be distinguished from other non-regulatory CD4 T cells?

Identify which of the following describes how antigen processing and presentation of self antigens by thymic epithelial cells differs from that of antigen-presenting cells in peripheral tissues.(Select all that apply.)

Elements of the Immune System and Their Roles in Defense

Innate Immunity: the Immediate Response to Infection

Innate Immunity: the Induced Response to Infection

Antibody Structure and the Generation of B-Cell Diversity

Antigen Recognition by T Lymphocytes

The Development of B Lymphocytes

T Cell-Mediated Immunity

Immunity Mediated by B Cells and Antibodies

Preventing Infection at Mucosal Surfaces

Immunological Memory and Vaccination

Coevolution of Innate and Adaptive Immunity

Failures of the Bodys Defenses

Ige-Mediated Immunity and Allergy

Transplantation of Tissues and Organs

Disruption of Healthy Tissue by the Adaptive Immune Response

Cancer and Its Interactions With the Immune System

Filters

Exam 7: The Development of T Lymphocytes

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED)is caused by a defect in

Genetic deficiencies in all of the following would impair the development of a fully functional T-cell repertoire except

Thymocytes that are not positively selected

Which of the following statements is correct?

If a double-negative thymocyte has just completed a productive β-chain gene rearrangement,which of the following describes the immediate next step in the development of this thymocyte?

Immediately after positive selection

In which of the following ways does the developmental pathway of α:β T cells differ from that of B cells? (Select all that apply.)

Which of the following is mismatched:

A.What is Notch1? B.Which cells express the ligand of Notch1? C.How does the interaction between Notch1 and its ligand mediate T-cell development?

Which of the following statements regarding positive selection is correct?

Which of the following is the first stage of T-cell receptor gene rearrangement in α:β T cells?

Which of the following cell-surface glycoproteins is characteristic of stem cells,but stops being expressed when a cell has committed to the T-cell developmental pathway?

Individuals with a defective autoimmune regulator gene (AIRE)exhibit

If the process of positive selection did not occur,then

A.What is the role of regulatory CD4 T cells (Treg)? B.How can Treg be distinguished from other non-regulatory CD4 T cells?

Identify which of the following describes how antigen processing and presentation of self antigens by thymic epithelial cells differs from that of antigen-presenting cells in peripheral tissues.(Select all that apply.)

Elements of the Immune System and Their Roles in Defense

Innate Immunity: the Immediate Response to Infection

Innate Immunity: the Induced Response to Infection

Antibody Structure and the Generation of B-Cell Diversity

Antigen Recognition by T Lymphocytes

The Development of B Lymphocytes

T Cell-Mediated Immunity

Immunity Mediated by B Cells and Antibodies

Preventing Infection at Mucosal Surfaces

Immunological Memory and Vaccination

Coevolution of Innate and Adaptive Immunity

Failures of the Bodys Defenses

Ige-Mediated Immunity and Allergy

Transplantation of Tissues and Organs

Disruption of Healthy Tissue by the Adaptive Immune Response

Cancer and Its Interactions With the Immune System

Filters

A.What is the role of regulatory CD4 T cells (T_reg)? B.How can T_reg be distinguished from other non-regulatory CD4 T cells?