Immunology Exam 1

 

 

1. Which of the following generally does not apply to bone marrow (a primary lymphoid organ) and secondary lymphoid organs?

A) cellular proliferation
B) differentiation of lymphocytes
C) cellular interaction
D) antigen-dependent response
E) None of the above.

2. Which of the following apply uniquely to secondary lymphoid organs?

A) presence of precursor B and T cells
B) circulation of lymphocytes
C) terminal differentiation
D) cellular proliferation
E) All of the above.

3. Which of the following does not apply to "innate" immune mechanisms?

A) absence of specificity
B) activation by a stimulus
C) involvement of multiple cell types
D) a memory component

4. Which of the following is the major function of the lymphocytes?

A) innate immunity
B) inflammation
C) phagocytosis
D) acquired immunity
E) None of the above.

5. Removal of the bursa of Fabricius from a chicken results in

A) a markedly decreased number of circulating T lymphocytes.
B) anemia.
C) delayed rejection of skin graft.
D) low serum levels of antibodies in serum.
E) all of the above.
F) none of the above.

 

6. The germinal centers found in the cortical region of lymph nodes and the peripheral region of splenic periarteriolar lymphatic tissue

A) site of development of immature B and T cells
B) function in the removal of damaged erythrocytes from the circulation
C) act as the major source of stem cells and thus help to maintain hematopoiesis
D) provide an infrastructure that on antigenic stimulation contains large populations of B lymphocytes and plasma cells
E) are the sites of NK-cell differentiation

7. Which of the following statements is incorrect concerning TCR and Ig genes?

A) In both B- and T-cell precursors, multiple V-, D-, J-, and C-region genes exist in an unrearranged configuration.
B) Rearrangement of both TCR and Ig genes involves specific recombinase enzymes that bind to specific regions of the genome.
C) Both Ig and TCR are able to switch C-region usage.
D) Both Ig and TCR exhibit allelic exclusion.
E) Both Ig and the TCR use combinatorial association of V, D, and J genes and junctional imprecision to generate diversity.

 

 

8. The most common clinical consequence(s) of Complement C3 deficiency is (are)

A) increased incidence of tumors
B) increased susceptibility to viral infections
C) increased susceptibility to fungal infections
D) increased susceptibility to bacterial infections
E) all of the above

 

 

9. Interaction between which of these receptor-ligand pairs facilitates neutrophill migration through vessel walls?

A) CD40 Ligand (CD154) and CD40
B) CD28 and B7
C) LFA-1 and ICAM-1
D) CTLA-4 and B7
E) TCR and MHC class I or II

 

10. The primary and secondary antibody responses differ in

A) the predominant isotype generated.
B) the number of lymphocytes responding to antigen.
C) the speed at which antibodies appear in the serum.
D) the biologic functions manifested by the Ig isotypes produced.
E) All of the above.

 

11. Primary interactions between antigens and antibodies involve all of the following except

A) covalent bonds.
B) van der Waals forces.
C) hydrophobic forces.
D) electrostatic forces.
E) a very close fit between an epitope and the antibody.

 

12. The DNA for an H chain in a B cell making IgG2 antibody for diphtheria toxoid has the following structure: 5'— V17— D5 — J2 Cg2— Cg4— Ce— Ca2— 3' How many individual rearrangements were required to go from the embryonic DNA to this B-cell DNA?

A) 1
B) 2
C) 3
D) 4
E) none

 

13. The ability of a single B cell to express both IgM and IgD molecules on its surface at the same time is made possible by

A) allelic exclusion.
B) isotype switching.
C) simultaneous recognition of two distinct antigens.
D) selective RNA splicing.
E) use of genes from both parental chromosomes.

 

 

14. All the following are characteristics of both MHC class I and class II molecules except:

A) They are expressed codominantly.
B) They are expressed constitutively on all nucleated cells.
C) They are glycosylated polypeptides with domain structure.
D) They are involved in presentation of antigen fragments to T cells.
E) They are expressed on the surface membrane of B cells.

 

15. MHC class I molecules are important for which of the following?

A) binding to CD8 molecules on T cells
B) presenting exogenous antigen (e.g., bacterial protein) to B cells
C) presenting viral protein to antigen-presenting cells such as macrophages
D) binding to CD4 molecules on T cells
E) binding to Ig on B cells

 

16. Which of the following is incorrect concerning MHC class II molecules?

A) B cells may express different MHC class II molecules on their surface.
B) MHC class II molecules are synthesized in the endoplasmic reticulum of many cell types.
C) Genetically different individuals express different MHC class II alleles.
D) MHC class II molecules are associated with
b2-microglobulin on the cell surface.
E) A peptide that does not bind to an MHC class II molecule will not trigger a CD4+ T cell response.

 

17. Products of TAP-1 and -2 genes

A) bind
b2-microglobulin.
B) prevent peptide binding to MHC molecules.
C) are part of the proteasome.
D) transport peptides into the endoplasmic reticulum for binding to MHC class I.
E) transport peptides into the endoplasmic reticulum for binding to MHC class II.

 

18. Which of the following is incorrect concerning the processing of an antigen, such as a bacterial protein, in the acid compartments of the cell?

A) It results in production of potentially immunogenic peptides that associate with MHC class II molecules.
B) Predominantly exogenous antigens are processed by this pathway.
C) It may lead to activation of CD4+ T cells.
D) It may lead to the activation of CD8+ T cells.
E) Bacterially derived peptides displace a fragment of the invariant chain from the MHC class II binding groove.

 

19. Which of the following statements about the MHC is incorrect?

A) It codes for complement components.
B) It codes for both chains of the MHC class I molecule.
C) It codes for both chains of the MHC class II molecule.
D) It is associated with susceptibility and resistance to different diseases.
E) The total set of MHC alleles on the chromosome is known as the MHC haplotype.

 

20. When the sequences of different MHC class I molecules are compared, the variation between molecules is concentrated within which of the following?

A) Areas of the molecule that bind CD4
B) Areas of the molecule that bind to the T cell receptor and to the antigenic peptide
C)
b-2 microglobulin
D) the transmembrane domain of the
a chain
E) the
b1 domain (the N terminal domain of the b chain)

21. CD4

A) binds directly to peptide antigen.
B) binds to an invariant portion of MHC class I molecules.
C) binds to an invariant portion of MHC class II molecules.
D) binds to CD8 on the T cell surface.
E) binds to the peptide-binding site of MHC class II.

22. Consider VDJ rearrangement of the heavy chain variable gene segments in the mouse. The RSS downstream of each VH segment has a 23 bp spacer sequence. Which of the following statements is incorrect.

A). Recombination most often occurs between a gene segment flanked by a 12 bp RSS spacer.

B)  N-segments can be inserted at both V-D and D-J joints.

C)  Recombination requires both RAG1 and RAG2.

D). P nucleotides can be inserted into both coding and signal joints.

 

The last three questions deal with hypothetic clinical case studies. Hopefully you can apply what we have discussed in chapters 1-5 to treat these patients.  Have fun!

 

Select the most likely diagnosis to the vignettes (questions 23-25) below:

A) Leukocyte Adhesion Deficiency
B) Systemic Lupus Erythematosus
C) Hereditary Angioneurotic Edema
D) X-Linked Agammaglobulinemia
E) Severe Combined Immunodeficiency
F) Hyper IgM Type 2 Syndrome
G) Paroxysmal Nocturnal Hemoglobinuria
H) DiGeorge Syndrome
 I) Wiskott-Aldrich Syndrome
J) Selective IgA Deficiency

K) Graves Disease
L) Multiple Sclerosis

 

23.  A 2-year-old girl was admitted to the hospital after she developed a severe infection of the large intestine. She had a history of recurrent infections and impaired wound healing. She was previously hospitalized at 3 weeks of age because of swelling and redness around the umbilical stump and high fever. Laboratory tests revealed a high white blood count, normal proportions of B and T lymphocytes and normal levels of IgM, IgG and IgA antibodies. However an additional test demonstrated a lack of migration of lymphocytes to the site of a localized skin abrasion. Furthermore, flow cytometric analysis revealed that relatively few of the child's blood lymphocytes reacted with a monoclonal antibody to CD18.
     

24. A 12-year-old junior high school boy was taken to the emergency room because of severe abdominal pains, vomiting and localized swelling of the face. He was also having some difficulty breathing. A history of the patient and his family revealed that the boy suffered from recurrent episodes of abdominal pain since he was 4 years old, as did his mother and maternal grandmother. A complete immunological workup revealed markedly reduced levels of C4 and C1INH in the boy's blood.
 

25. A 4-year old boy with recurrent infections caused by Streptococcus pyogenes, Hemophilus influenza, and Pneumocystis carinii was admitted to the hospital following a 3-day sinus infection. His mother noted that he had developed a productive cough, now had a high fever. His white blood cell count was 4200/ul (normal count 5000-9000/ul). Twenty-six percent of his white cells were neutrophils (very low), 56% were lymphocytes (normal), and 28% were monocytes (elevated). A serum work-up revealed that his IgG (normal 600-1500 mg/dl) and IgA (normal 150-225 mg/dl) were undetectable.  However his IgM level was 210 mg/dl (normal 75-150 mg/dl). A flow cytometric analysis of his peripheral blood cells revealed that all of his B cells were IgM+, IgD+. What is this boy suffering from?