Exam 2: Set 2 Flashcards
A 2-year-old boy is evaluated for a severe combined immunodeficiency disease. His bone marrow has normal cellularity. Radioactive tracer studies demonstrate a normal number of T-cell precursors entering the thymus, but no mature T lymphocytes are found in the blood or peripheral organs. Cells populating the thymus are found to lack CD3. Which of the following capabilities would his cells lack?
A. Ability to bind cell-bound peptides
B. Ability to express CD4/CD8 coreceptors
C. Ability to produce terminal deoxynucleotidyl transferase
D. Ability to proliferate in response to specific antigen
E. Ability to rearrange T-cell receptor gene segments
D. Ability to proliferate in response to specific antigen
Isotype switching during B-cell ontogeny dedicates mature B cells to production of a single heavy chain isotype, except in the case of IgM and IgD, which can be expressed concomitantly. How is this expression of both isotypes simultaneously possible?
A. Allelic exclusion B. Allelic codominance C. Affinity maturation D. Alternative RNA splicing E. Somatic hypermutation
D. Alternative RNA splicing
A 12-year-olf boy is diagnosed with a T cell lymphoma. The phenotype of the malignant cells matches that of normal progenitor cells that leave the bone marrow to enter the thymus. What cell surface markers would you expect to find on the malignant cells?
A. CD4-, CD8-, TCR- B. CD4-, CD8-, TCR+ C. CD4-, CD8+, TCR+ D. CD4+, CD8-, TCR+ E. CD4+, CD8+, TCR+
A. CD4-, CD8-, TCR-
Herpes simplex viruses are extremely successful pathogens because they have a variety of immunologic evasion mechanisms. For example, both HSV 1 and 2 depress the expression of MHC class I molecules on the surface of infected cells. Which coreceptor’s binding would be inhibited by this evasion mechanism?
A. CD2 B. CD4 C. CD8 D. CD16 E. CD56
C. CD8
A young woman with acute myeloblastic leukemia is treated with intensive chemotherapy and achieves remission of her symptoms. Because the prog-nosis for relapse is relatively high, a bone marrow transplant is undertaken in her first remission. Which of the following cytokines administered with the bone marrow cells would have the beneficial result of stimulating lymphoid-cell development from the grafted stem cells?
A. IL-1 B. IL-2 C. IL-3 D. IL-6 E. IL-7
E. IL-7
A patient with advanced metastatic melanoma decides to join an experimental treatment protocol in the hope that it will cause regression of hi tumor masses. Malignant cells are aspirated from several of his lesions an transfected in vitro with the gene encoding IL-3 production. The transfected tumor cells are then reinfused into the patient. Mobilization of which of the following cells from the bone marrow would be likely to result from this treatment?
A. Antigen-presenting cells B. B lymphocytes C. NK cells D. Plasma cells E. T lymphocytes
A. Antigen-presenting cells
An 8-year-old boy is diagnosed with acute lymphoblastic leukemia. Flow cytometry is used to determine the immunophenotype of the malignant cells. The patient’s cells are evaluated with monoclonal antibodies for MHC class II, CD19, and CD34, and are found to have high levels of fluorescence with all of these markers. They also possess cytoplasmic heavy chains. What is the developmental stage of these cells?
A. Immature B cell B. Lymphoid progenitor cell C. Mature B cell D. Pre-B cell E. Pro-B cell
D. Pre-B cell
The blood from an 8-year-old boy was analyzed by flow cytometry. The cells were treated with fluorescent-labeled antibodies to various cell surface markers before they were evaluated by flow cytometry. Which of the following markers would identify the B lymphocytes in the sample?
A. CD3 B. CD4 C. CD8 D. CD19 E. CD56
D. CD19
An 18-year-old member of a college soccer team is seen by a physician because of chest tightness and dyspnea on exertion. A 15-cm mediastinal mass is detected radiographically. Eighty percent of the white blood cells in the peripheral blood are small, abnormal lymphocytes with lobulated nuclei and scant cytoplasm. Immunophenotyping of the abnormal cells shows them to be CD4+ and CD8+. Where such cells would normally be found in the body?
A. Bone marrow B. Peripheral blood C. Thymic cortex D. Thymic medulla E. Splenic periarteriolar lymphoid sheaths
C. Thymic cortex
- A patient with a B-cell lymphoma is referred to an oncology clinic for the analysis of his condition. The malignant cells are found to be producing IgM monomers. Which of the following therapeutic regimens is most likely to destroy the malignant cells and no others?
A. Anti-CD3 antibodies plus complement
B. Anti-CD19 antibodies plus complement
C. Anti-CD20 antibodies plus complement
D. Anti-idiotype antibodies plus complement
E. Anti-u chain antibodies plus complement
D. Anti-idiotype antibodies plus complement
A lymph node biopsy of a 6-year-old boy shows markedly decreased numbers of lymphocytes in the paracortical areas. Analysis of his peripheral blood leukocytes is likely to show normal to elevated numbers of cells expressing which of the following surface marker?
A. CD2 B. CD3 C. CD4 D. CD8 E. CD19
E. CD19
A 6-year-old child is taken to his pediatrician because the parents are alarmed about an indurated fluctuant mass on the posterior aspect of his neck. The mass is nontender and shows no signs of inflammation. The child is examined carefully, and no other masses are found. The pediatrician decides to submit a biopsy of this area to a pathologist. The pathologist reports back that the mass is a lymph node with markedly increased numbers of cells in the cortical area. Fluorescent antisera to which of the cell surface markers is most likely to bind to cells in this area?
A. CD2 B. CD3 C. CD4 D. CD16 E. CD19
E. CD19
