Molecular Immunology

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Dr. Tamma BMS 687, Molecular Immunology. Exam 2

 

 

An 8 month old boy who had several major bacterial and viral infections over the past 3 months

was recently referred to an immunologist by his pediatrician. Diagnostic tests revealed that this

patient has a SCID immunodeficiency disease and negligible numbers of both B and T

lymphocytes. Analysis of DNA obtained from the child’s peripheral B cells revealed that both

heavy chain alleles were in the following configuration:

 

 

V1 V2 V3 V4 Vn D1 D2 D3 Dn J1 J2 J3 Jn

 

 

 

 

 

1. The above gene configuration is representative of:

 

A. The germline heavy chain locus

B. The gemline kappa light chain locus

C. The rearranged heavy chain locus

D. The rearranged kappa light chain locus

E. The rearranged lambda light chain locus

 

 

2. Which of the following statements is most likely correct?

 

A. The patient is unable to rearrange his heavy chain genes only

B. The patient is unable to rearrange his T cell receptor genes only

C. The patient is unable to rearrange his heavy and light chain genes only

D. The patient is unable to rearrange his immunoglobulin and T cell receptor genes

 

 

3. The likely cause of this immunodeficiency is the following:

 

A. Jak 3 kinase deficiency

B. Adenosine deaminase deficiency

C. RAG2 deficiency

D. Btk deficiency

E. IL2-R alpha chain deficiency

 

 

4. The BEST type of treatment for this patient would be:

 

A. Bone marrow transplantation

B. Intravenous gamma globulin (IVGG)

 

 

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C. Antibiotics

D. Corticosteroids

E. Co-stimulatory blockade

Your patient, who is a 36 year old woman with lupus, has recently been found to have elevated

levels of protein and traces of blood in her urine. You suspect that she may be developing

nephritis caused by the deposition of IgG antibodies and immune complexes in her kidney and

have requested a kidney biopsy.

 

5. What assay would best help you detect the presence of IgG antibody in a tissue biopsy

obtained from her kidney?

 

A. ELISA

B. Immunofluorescence microscopy

C. Western blot

D. FACS analysis

E. Coombs test

 

6. Which one of the following properties of antibodies is NOT dependent on the structure of the

heavy-chain constant region? What would be the best answer?

 

A. Ability to cross the placenta

B. Isotype (class)

C. Ability to fix complement

D. Ability to promote opsonization

E. Affinity for antigen

 

 

7. The germinal centers in the lymph nodes and spleen are the major sites of the following

EXCEPT:

 

A. B and T cell activation

B. Isotype switching

C. Somatic mutation

D. Lymphocyte development

E. Plasma cell formation

 

 

8. The membrane IgM and IgD on the surface of an individual B-cell

 

A. Have identical heavy chains but different light chains

B. Are identical except for their CH regions

C. Are identical except for their VH regions

D. Have different VH and VL regions

 

9. An individual who is heterozygous for the gamma heavy chain allotype (Gm) contains two

allelic forms of IgG in serum, but individual lymphocytes produce only one of the two forms.

 

 

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This phenomenon, known as allelic exclusion is consistent with:

A. functional rearrangement of a heavy chain gene on only chromosome in a B- cell

B. Functional rearrangements of heavy chain genes on both chromosomes in a B- cell

C. Functional rearrangements of light chain genes on both chromosomes in a B- cell

D. Alternative RNA splicing of immunoglobulin heavy chain genes in different B-cells

 

10. Chronic passive immunoglobulin administration is a reasonable therapy for all of the

following immunodeficiency disorders EXCEPT:

 

A. Bruton’s type hypogammaglobulinemia

B. Transient hypogammaglobulinemia of infancy

C. IgG deficiency with high IgM

D. Hypogammaglobulinemia

E. Selective IgA deficiency

 

11. John, a 14-month-old boy with severe gram-positive bacterial pneumonia, is referred to the

Children’s Hospital by the family physician. This is his third such infection In 4 months. He has

two healthy sisters aged 3 and 5 years. The family lost a boy at 10 months of age to bacterial

pneumonia 6 years ago. The family doctor has sent along some blood test results that show low

serum immunoglobulin levels (all classes), few B cells, but normal numbers and functioning of T

cells. Which one of the following is the most likely diagnosis?

 

A. X-linked hypogammaglobulinemia

B. Common variable hypogammaglobulinemia

C. Transient hypogammaglobulinemia of infancy

D. CD40 genetic defect

E. Severe combined immunodeficiency

 

12. A 25-year-old woman went to see her physician complaining of being tired and run down.

Because of her lack of energy, she had given up her regular exercise program, a routine she had

maintained for a number of years. Until a year ago she had been very active and considered

herself in excellent physical condition. However, in the last year she had experienced several

protracted colds and three vaginal yeast infections, which had not previously been a problem.

During the physical examination the physician noted that several of her lymph nodes were

enlarged, yet no present infection was evident. She admits to multiple sexual partners, and since

she uses birth control pills she never uses condoms. The general practitioner ordered a series of

tests to measure her immune system. Her tests revealed a lower than normal CD4+ T cell count.

What type of infection would manifest in this manner?

 

A. HIV infection

B. Any virus

C. Bacterial

D. Fungal

E. Parasitic

 

 

 

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13. A young mother living in Africa is HIV positive and has just given birth to a baby girl. As

her physician you are to advise her whether to breast feed her infant. Because this is a region in

Africa where many children die of gastrointestinal infections, you are in a dilemma as to what

to advise. Furthermore, you know that breast feeding has been shown to be protective for the

infant. Breast feeding protects the infant from infections because the mother’s following are

passively acquired by the nursing infant.

 

A. IgA antibodies (secretory IgA)

B. IgM antibodies

C. IgE antibodies

D. Natural killer cells

E. Hemagglutinins

 

14. Joan is a 17-year-old girl who comes to your emergency department in the terminal stages of

delivery. You determine this to be an uneventful pregnancy (she is now 39 weeks of gestation).

She has had essentially no antenatal care. She delivered a healthy baby boy, and the delivery

itself is uncomplicated. You order the nurse to give Joan an injection of RhoGam. The rationale

for this is that you are concerned that the

 

A. Mother is Rh- and the baby is Rh+

B. Father is Rh+ and the baby is Rh-

C. Mother is Rh+ and the baby is Rh-

D. Father is Rh— and the baby is Rh+

E. Father and the baby are both Rh-, while the mother is Rh+

 

15. Jane, a 15-month-old infant, was brought to her family practice clinic for her routine well-

child examination. During the course of the office visit, Jane received her first measles

immunization. For successful immunization leading to formation of specific memory cells, all

the following cell types would need to be activated EXCEPT

 

A. T cells

B. B cells

C. Dendritic cells

D. Eosinophils