1. B lymphocytes are made in the: A. blood stream. B. bone marrow. C. liver. D. thymus. E. totipotent cell. -answer Answer: B Section: Introduction Difficulty: 1 Hint: Location of B cell production from a HSC. 2. How long does B cell maturation from an

1. B lymphocytes are made in the: A. blood stream. B. bone marrow. C. liver. D. thymus. E. totipotent cell. -answer Answer: B Section: Introduction Difficulty: 1 Hint: Location of B cell production from a HSC. 2. How long does B cell maturation from an HSC to a mature B cell take? A. 1 to 2 hours B. 1 to 2 days C. 1 to 2 weeks D. 1 to 2 months E. 1 to 2 years -answer Answer: C Section: Introduction Difficulty: 1 Hint: B cell will begin to secrete antibodies within a few days of infection. 3. Which cell type is found in both B- and T-cell lineages? A. Common lymphoid progenitors B. Common pro-B-T cells C. Immature B cell D. Naïve lymphoid progenitor E. Pro-B-T cell -answer Answer: A Section: Introduction Difficulty: 1 Hint: B cells belong to the lymphoid lineage. 4. This type of cell will leave the bone marrow and complete maturation in the spleen. A. Common lymphoid progenitor cell B. hematopoietic stem cell C. immature B cell D. pro-B cell E. pro-T cell -answer Answer: C Section: Introduction Difficulty: 1 Hint: B cells will see potential antigens in the germinal centers of secondary lymphoid organs such as the spleen. 5. All of the following are true regarding B-cell development EXCEPT: A. B cells complete maturation in the spleen. B. B cells are mostly developed when they leave the bone marrow. C. B cells, like T cells, are MHC class restricted. D. Self-reactive B cells may be eliminated though apoptosis. E. Self- reactive B cells may be rendered unreactive (anergic). -answer Answer: C Section: Introduction Difficulty: 2 Hint: B cells display IgD as their BCR. 6. Hematopoiesis produces: A. B cells only. B. Red blood cells only. C. myeloid lineage cells only. D. lymphoid and myeloid lineage cells. E. erythorid, lymphoid, and myeloid lineage cells. -answer Answer: E Section: The Site of Hematopoiesis Difficulty: 2 Hint: Hematopoietic stem cells produce all blood cells. 7. Hematopoiesis begins at around day 7 after fertilization in mice. What is the site of precursor cells at this stage of fetal development? A. Bone marrow B. Fetal liver C. Placenta D. Primitive organ E. Yolk sac -answer Answer: E Section: The Site of Hematopoiesis Difficulty: 2 Hint: Developing embryos do not make bone marrow until the later stages of fetal development. 8. At what site can fetal HSCs be found by day 8 in the mouse model? A. AGM (aorta-gonad-mesonephros) B. Bone marrow C. Fetal liver D. Placenta E. Yolk -answer Answer: A Section: The Site of Hematopoiesis Difficulty: 2 Hint: The AGM will develop into bone marrow during the later stages of fetal development. 9. At what site(s) can mature HSCs be found by day 11 in the mouse model? A. AGM B. Fetal liver C. Placenta D. Yolk E. All of the above -answer Answer: E Section: The Site of Hematopoiesis Difficulty: 2 Hint: Mice have a short gestation period so day 11 represents the half-way point of fetal development. At this point, mature HSCs can be found throughout the developing embryo. 10. What type of cell will predominately be produced by hematopoiesis in the fetal liver of mice? A. Erythroid lineage cells B. Lymphoid lineage cells C. Myeloid lineage cells only D. Lymphoid and myeloid lineage cells E. Erythorid, lymphoid, and myeloid lineage cells -answer Answer: A Section: The Site of Hematopoiesis Difficulty: 2 Hint: Red blood cell development occurs in the liver. 11. VDJ recombination occurs during which phase of a B cell's development? A. Activated B cell B. Mature B cell C. Naïve B cell D. Pro-B cell E. Immature B cell -answer Answer: D Section: B-Cell Development in the Bone Marrow Difficulty: 1 Hint: VDJ rearrangement takes place while B cells develop in the bone marrow. Unsuccessful recombinations in young B cells result in apoptosis. 12. What are two functions of bone marrow stromal cells with respect to B-cell development? A. Cytokine expression and traps developing B cells in a specific location B. Recruits macrophages to phagocytize self-recognizing B cells and decreases HSC when no active infection is present C. Secretes release factors that direct the B cell to the spleen and expresses necessary cytokines D. Traps developing B cells in a specific location and recruits red bloods to bring oxygen to developing B cells E. Triggers HSCs to produce more pro-B cells and secretes cytokines to stimulate osteoblast development -answer Answer: A Section: B-Cell Development in the Bone Marrow Difficulty: 2 Hint: Bone marrow stromal cells provide the proper environment for B cell development. 13. Individuals of retirement age or older show lower antibody mediate immune responses due to all of the following reasons EXCEPT: A. increased likelihood of autoimmune disorders. B. limited HSC production of pro-B cells. C. poor antibody response to vaccination. D. reduced-memory B-cell generation. E. smaller thymus. -answer Answer: E Section: B-Cell Development in the Bone Marrow Difficulty: 2 Hint: B-cell production and the checkpoints that ensure only non-self-recognizing B cells are allowed to live decreases as an individual ages. 14. What type of immunoglobulin gene rearrangement occurs during B-cell progenitor development? A. DH-JH rearrangement B. DL-JL rearrangement C. Both heavy- and light-chain rearrangement D. VH-DJH rearrangement E. VL-DJL rearrangement -answer Answer: C Section: B-Cell Development in the Bone Marrow Difficulty: 2 Hint: B cells must have a functional BCR (IgD) before leaving the bone marrow. 15. The common lymphoid progenitor cell gives rise to all of the following cell lines EXCEPT: A. dendritic cells. B. megakaryocytes. C. natural killer cells. D. pre-pro B cells. E. T-cell progenitor. -answer Answer: B Section: B-Cell Development in the Bone Marrow Difficulty: 2 Hint: Megakaryocytes produce platelets (thrombocytes). 16. Which of the following statements regarding HSCs is/are TRUE? I. HSCs are not self-renewing. II. HSCs can make copies of themselves. III. HSCs give rise to one cell lineage. IV. HSCs are multipotent. V. HSCs express both Rag 1 and Rag 2 surface markers. A. Statement I only B. Statements I and III only C. Statements II and III only D. Statements II and IV only E. Statements III and V only -answer Answer: D Section: B-Cell Development in the Bone Marrow Difficulty: 2 Hint: Multipotent cells are self-renewing and give rise to multiple cell lines. 17. Where can early lymphoid progenitor cells (ELPs) be found in humans? A. Blood stream B. Bone marrow C. Lymphatic tissue D. Thymus E. Both B and C -answer Answer: B Section: B-Cell Development in the Bone Marrow Difficulty: 2 Hint: ELPs are young common lymphoid progenitor cells that will give rise to NK cells, B cells, and T cells. 18. At what stage of development does a B cell begin to express a pre-B-cell receptor? A. Pre-pro B cell B. Early pro-B cell C. Late pro-B cell D. Late pre-B cell E. Immature B cell -answer Answer: D Section: B-Cell Development in the Bone Marrow Difficulty: 2 Hint: Pre-BCRs are expressed immediately after VH-DJH rearrangement. 19. At what stage of development does a B cell undergo D-JH rearrangement? A. Pre-pro B cell B. Early pro-B cell C. Late pro-B cell D. Late pre-B cell E. Immature B cell -answer Answer: B Section: B-Cell Development in the Bone Marrow Difficulty: 2 Hint: The first checkpoint for self-reactivity with a B cell is VH-DJH rearrangement. 20. At what stage of development does a B cell begin to display an IgM receptor? A. Pre-pro B cell B. Early pro-B cell C. Late pro-B cell D. Late pre-B cell E. Immature B cell -answer Answer: E Section: B-Cell Development in the Bone Marrow Difficulty: 2 Hint: IgM is the first Ig displayed on a developing B cell, and it is functional just before the second checkpoint for self-reactivity during B-cell development. 21. B-cell development has one checkpoint to determine if V-DJ rearrangement has produced a successful VH-DJH combination that does not recognize self. If no successful combination is produced, then the B cell will undergo apoptosis. At what point of B-cell development does this checkpoint occur? A. Pre-pro B cell B. Early pro B cell C. Late pro B cell D. Late pre B cell E. Immature B cell -answer Answer: C Section: B-Cell Development in the Bone Marrow Difficulty: 2 Hint: VH-DJH rearrangement occurs during the late pro-B cell phase. 22. How does allelic exclusion prevent multiple heavy-chain rearrangements from occurring in pre-B cells? A. RAG1 and RAG2 are down-regulated, and TdT activity is lost so that no additional heavy-chain rearrangements may take place. B. RAG1 is up-regulated while RAG2 and TdT are down-regulated to prevent heavy-chain recombination on the second set of chromosomes. C. RAG1 and RAG2 induce silencing of the second alleles for VH-DJH rearrangement. D. TdT initiates light-chain rearrangement. E. TdT releases a cytokine to trigger apoptosis in the pre-B cell. -answer Answer: A Section: B-Cell Development in the Bone Marrow Difficulty: 3 Hint: RAG1, RAG2, and TdT are signals that allow heavy-chain rearrangement. 23. Mature naïve B cells express high levels of ____ on their cell surfaces. A. IgA B. IgD C. IgE D. IgG E. IgM -answer Answer: B Section: B-Cell Development in the Bone Marrow Difficulty: 1 Hint: Membrane-bound IgD serves as the BCR. 24. Mature B-2 or follicular B cells are most commonly found in the: A. bone marrow. B. lymph node. C. marginal zones of the spleen. D. peritoneal. E. secondary lymphoid organs. -answer Answer: E Section: The Development of B-1 and Marginal-Zone B Cells Difficulty: 2 Hint: B-2 cells are the conventional B cells found in germinal centers of the spleen, Peyer's patch, MALT, skin, tonsils, and adenoids. 25. Mature B-1 cells show ______ diversity in their V-region. A. high B. moderate (somewhat restricted) C. low (restricted) D. high or low depending on active infection E. high or low depending on CD21 expression -answer Answer: C Section: The Development of B-1 and Marginal-Zone B Cells Difficulty: 1 Hint: B-1 cells reside in the peritoneal and pleural cavities and typically target carbohydrate antigens. 26. Marginal-zone B cells express: A. IgD. B. IgG. C. IgM. D. IgE. E. Both B and C -answer Answer: E Section: The Development of B-1 and Marginal-Zone B Cells Difficulty: 1 Hint: Marginal-zone B cells are designed to recognize and respond to blood-borne antigens. 27. Which type of mature B cell is MOST likely to respond to a protein antigen? A. B-1 B cells B. B-2 B cells C. MZ B cells D. B-2 B cells and MZ B cells E. B-1 B cells, B-2 B cells, and MZ B cells -answer Answer: D Section: The Development of B-1 and Marginal-Zone B Cells Difficulty: 2 Hint: B cells that target protein or peptide antigens show higher variable region diversity than B cells that target carbohydrate antigens. 28. What is the initial location of B-cell and T-cell development? A. Blood for B cell and thymus for T cell B. Bone marrow for both B cell and T cell C. Bone marrow for B cell and thymus for T cell D. Secondary lymphoid organs for B cell and thymus for T cell E. Thymus for both B cell and T cell -answer Answer: B Section: Comparison of B- and T-Cell Development Difficulty: 1 Hint: B cells and T cells come from a common lymphoid progenitor cells. 29. Which cell type undergoes negative selection of ectopic expressing self-antigen cells in primary lymphoid organs? A. B cells B. MZ B cells C. T cells D. Both B cells and T cells E. Neither B cells nor T cells -answer Answer: C Section: Comparison of B- and T-Cell Development Difficulty: 1 Hint: B cells that bind self-antigens are selected against during B-cell development while T-cell selection occurs in the thymus. 30. V-J rearrangement occurs in: A. all B cells. B. all T cells. C. only B-1 B cells. D. only B-2 B cells. E. both B cells and T cells. -answer Answer: E Section: Comparison of B- and T-Cell Development Difficulty: 1 Hint: The BCR and TCR undergo V-J rearrangement during development.