Exam 6: The Development of B Lymphocytes

A.What are the two main checkpoints of B-cell development in the bone marrow? B.What is the fate of developing B cells that produce (i)functional or (ii)nonfunctional heavy and light chains? C.Explain how these two checkpoints correlate with the process of allelic exclusion that ensures that only one heavy-chain locus and one light-chain locus produce functional gene products.

Which of the following is true of centrocytes? (Select all that apply.)

Which of the following statements is correct?

Hinda Mundy,26 years old,grew concerned when a lump appeared in her lower neck and she had pain in her chest and a dry cough.She also told her physician that she had experienced fatigue,night sweats,unintentional weight loss,pruritis (dry,itchy skin),and intermittent fevers over the past few months.Immunohistological staining of a biopsy of the enlarged lymph node revealed the presence of large multinucleated Reed-Sternberg cells.Polymerase chain reaction (PCR)tests confirmed immunoglobulin gene rearrangements; however,B-cell antigen expression was absent.Hinda entered complete remission after treatment with four cycles of chemotherapy combined with radiotherapy.These symptoms and treatment are most consistent with a diagnosis of

A. Explain why immunological memory is important in acquired immunity. B.Describe how immunoglobulin expressed during a primary immune response differs qualitatively and quantitatively from the immunoglobulin expressed during a secondary immune response.