B cell selection

The proto-oncogene _______ is associated with the development of Burkitt s lymphoma.

a. BCL-2 b. Myc c. CD5 d. CD19 e. BTK

Identify the mismatched pair of chemokine and the cells that secrete it.

a. CCL19: lymph-node dendritic cells b. CXCL13: follicular dendritic cells c. CCL21: stromal cells of secondary lymphoid tissues d. All of the above are correctly matched. e. None of the above is correctly matched.

What is the fate of an immature B cell that encounters and has specificity for self antigen?

a. If further heavy-chain and light-chain gene rearrangements are possible, it undergoes apoptosis. b. Somatic hypermutation. c. Decrease in production of IgD. d. Continued rearrangement of heavy-chain genes. e. Continued rearrangement of light-chain genes.

Which of the following pertains to the fate of immature B cells that have specificity for univalent self antigens?

a. The cells acquire a state of unresponsiveness called anergy. b. IgD is retained in the cytosol. c. IgD on the cell surface activate the B cell when bound to self antigen. d. The cells have a much longer life-span than mature B cells. e. The cells die by apoptosis.

All of the following are associated with the development of Burkitt s lymphoma except:

a. The expression of Myc protein is perturbed. b. A chromosomal translocation involving a proto-oncogene and an immunoglobulin gene occurs. c. Overproduction of the Bcl-2 protein prolongs the lifetime of B-lineage cells. d. Cell division restraints on mutated B cells are lifted. e. In addition to a chromosomal translocation event, mutations elsewhere in the genome are usually involved.

Which of the following statements about the IgD made by B cells of upper respiratory mucosa is not true?

a. These antibodies bind to airborne bacteria such as Haemophilus influenzae. b. lambda light chains are used almost exclusively by these IgD antibodies. c. Two-thirds of these IgD antibodies possess kappa light chains. d. These IgD antibodies recruit basophils and induce the secretion of antibacterial peptides. e. kappa light chains are used almost exclusively by these IgD antibodies.

Which of the following characterizes the B-1 cells that develop prenatally?

a. They lack N nucleotides. b. They possess polyspecificity for bacterial polysaccharide antigens. c. They arise early in embryonic development preceding the development of the majority subset of B cells. d. They have little or no IgD on the cell surface. e. All of the above.

When producing monoclonal antibodies, why is it important to use as a fusion partner a myeloma cell that is unable to produce its own immunoglobulin?

a. To ensure that allelic exclusion of mu chain occurs normally. b. To ensure that the antibodies are homogeneous and able to make strong bivalent attachments to multivalent antigens. c. To ensure that the monoclonal antibodies are not autoreactive. d. To provide a greater opportunity for making a successful rearrangement at the light-chain locus. e. To ensure that antibodies are secreted and not membrane-bound.

The circulatory route through a lymphoid tissue for both immature B cells and mature B cells that do not encounter specific antigen is:

a. bloodstream --> HEV of lymphoid cortex --> primary lymphoid follicle --> efferent lymphatic vessel b. afferent lymphatic vessel --> primary lymphoid follicle --> HEV of lymphoid cortex --> efferent lymphatic vessel c. afferent lymphatic vessel --> medullary cords --> primary lymphoid follicle --> efferent lymphatic vessel d. primary lymphoid follicle --> HEV of lymphoid cortex --> afferent lymphatic vessel --> efferent lymphatic vessel e. bloodstream --> afferent lymphatic vessel --> HEV of lymphoid cortex --> efferent lymphatic vessel

In which location would plasma cells not be present?

a. bone marrow b. afferent lymphatic vessels c. medullary cords of lymph nodes d. lamina propria of gut-associated lymphoid tissues e. efferent lymphatic vessels

Immunological tolerance in the B-cell repertoire is called _______ tolerance when it develops in primary lymphoid organs, and _______ tolerance when it is induced outside the bone marrow.

a. primary; secondary b. apoptotic; anergic c. stromal; follicular d. receptor-mediated; systemic e. central; peripheral

All of the following events occur within germinal centers except:

a. production of memory B cells b. isotype switching c. centroblasts arise from activated B cells d. B cells are activated by CD4 helper T cells e. affinity maturation

All of the following participate in signal transduction in developing B cells except:

a. terminal deoxynucleotidyl transferase (TdT) b. FLT3 c. CD19 d. Igalpha and Igbeta e. Bruton tyrosine kinase (Btk)

Negative selection of developing B cells ensures that ___________.

a. there is not an overabundance of circulating B cells that would compete with other important cell types in the circulation b. only antigen-activated B cells leave the bone marrow c. clonal expansion of B cells does not occur in the absence of infection d. B-cell receptors that bind to normal constituents of the body do not emerge e. B cells do not leave secondary lymphoid tissues

Plasma cells have all of the properties listed except ______________.

a. they rapidly proliferate in secondary lymphoid follicles b. they secrete antibody and they are terminally differentiated B cells c. they no longer express MHC class II molecules d. they cease expressing membrane-bound immunoglobulin