Exam 3: B cells Flashcards
Which of the following statements is correct?
The kappa light-chain genes rearrange before the lambda light-chain genes.
Which of the following cell-surface markers differentiates hematopoietic stem cells from other cell constituents in the bone marrow?
CD34
The consequence of allelic exclusion at the immunoglobulin loci ensures that _____.
B cells express antigen receptors of a single specificity and homogeneous B-cell receptors bind more effectively to antigens
Which of the following is characteristic of a large pre-B cell?
VDJ is successfully rearranged and µ(mu) heavy chain is made
Which of the following is not paired with its correct complement?
Large pre B-cell stage: constitutive expression of RAG-1 and RAG-2 proteins
A defect in which of the following proteins blocks B-cell development at the pre-B-cell stage, resulting in almost no circulating antibodies in individuals with this defect?
Bruton tyrosine kinase (Btk)
Which of the following would occur after the production of a functional mu chain as a pre-B-cell receptor?
RaG proteins are degraded
Chromatin structure of heavy-chain locus is recognized to prevent gene rearrangement
Transcription of RAG 1 and RAG 2 genes ceases
There is allelic exclusion of a second mu chain
All of the above IS ANSWER
Large pre-B cells are characterized by which of the following?
The mu chain is assembled w/ Vpre-lambda5
An important advantage of having two gene loci (kappa and lambda) for the light chain is ________.
That the likelihood of a successful rearrangement of light-chain genes increases
The latest stages of late pro-B-cell development are recognized by the association of a surrogate light chain with a mu chain. The surrogate light chain is composed of _______.
VpreB and lambda5
Immature B cells develop into B cells in the _______________.
Secondary lymphoid organs
All hematopoietic stem cells express ___________.
CD34
A developing B cell unable to generate a productive rearrangement on any of the four light-chain loci will undergo _____________.
Apoptosis
In which location would plasma cells not be present?
Afferent lymphatic vessels
Which of the following is a characteristic of B-2 cells?
They are located primarily in the secondary lymphoid organs
Identify the mismatched pair of chemokine and the cells that secrete it.
CCL19 : lymph-dendritic cells CXCL13: follicular dendritic cells CCL21: stromal cells of secondary lymphoid tissues ALL OF THE ABOVE is the answer
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.
Central; peripheral
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?
To ensure that the antibodies are homogenous and able to male strong bivalent attachments to multivalent antigens
Which of the following pertains to the fate of immature B cells that have specificity for univalent self-antigens?
The cells acquire a state of unresponsiveness called Anergy
Which of the following statements about the IgD made by B cells of upper respiratory mucosa is not true?
Two-thirds of these IgD antibodies possess kappa light chains
All of the following events occur within germinal centers except:
B cells are activated by CD4 helper T cells
The proto-oncogene _______ is associated with the development of Burkitt s lymphoma.
Myc
Which of the following characterizes the B-1 cells that develop prenatally?
Lack N nucleotides
Possess polyspecificity for bacterial polysaccharide antigens
Arise early in embryotic development preceding development of majority of subset B cells
Have little to no IgD on the cell surface
ALL OF THE ABOVE
Receptor editing occurs _____.
In bone marrow to establish self-tolerance of the B-cell repertoire
All of the following participate in signal transduction in developing B cells except:
Terminal deoxynucleotidyl transferase (TdT)
Negative selection of developing B cells ensures that ___________.
B-cell receptors that bind to normal constituents of the body do not emerge
Plasma cells have all the properties listed except ______________.
Rapidly proliferate in secondary lymphoid follicles
The circulatory route through a lymphoid tissue for both immature B cells and mature B cells that do not encounter specific antigen is:
bloodstream –> HEV of lymphoid cortex –> primary lymphoid follicle –> efferent lymphatic vessel
