The earliest stages of B-cell differentiation
Which of the following is expressed on the surface of the mature B lymphocyte?
Which of the following statements is
Immature B lymphocytes
Antigen binding to the B-cell receptor
Which of the following would
not be found on a memory B cell:
A 19-year-old African-American presents to her primary care physician with an extranodal mass involving the mandible. Biopsy revealed lymphoma cells with the following characteristics: germline TCR genes, surface IgM+, surface IgD+, CD19+. What normal cell component markers are most similar to those expressed by the lymphoma cell?
In B cell development when the heavy chain first rearranges it may be expressed on the cell surface prior to light chain rearrangement. If this occurs, the heavy chain is associated with which of the following on the surface of the cell?
Answers to Review Questions
1. E The earliest events in B-cell differentiation take place in fetal liver and bone marrow in the adult and involve rearrangement of heavy-chain V, D, and J gene segments.
2. E All the molecules are expressed on the surface of the mature B cell.
3. C Antibody synthesis in secondary responses occurs predominantly in lymph nodes, not blood.
4. D In immature B cells, which express only IgM, contact with antigen leads to unresponsiveness rather than activation.
5 C. The molecules Iga and Igb, which are associated with the surface Ig molecule, transduce a signal following antigen binding to surface Ig.
6. D Surrogate light chains are expressed only at the pre-B cell stage of B-cell differentiation.
7. C The surface expression of IgM, IgD, and CD19 is characteristic of mature B cells.
8. C In the early stages of B cell development, the heavy chain is first expressed on the cell surface in association with the non-rearranged molecules VpreB and l5, known as the surrogate light chains.
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