B Cell Development: Key Concepts

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Where do pluripotent stem cells give rise to distinct B and T cell lineages?

Bone marrow

Where are protein antigens recognized by specific B and T lymphocytes?

Peripheral lymphoid organs

What is the lifespan of extrafollicular plasma cells?

Short-lived (~3 days)

Where do follicular/germinal center plasma cells migrate to?

Bone marrow, MALT Signup and view all the answers

How are naive B cells activated in the follicles?

By the same antigen (in its native conformation) transported there Signup and view all the answers

Where are naive CD4+ T cells activated by antigen processed and presented by dendritic cells?

T cell zones Signup and view all the answers

Where do helper T cells and activated B cells interact to initiate the initial antibody response?

Edges of the follicles Signup and view all the answers

Where do most immature B cells complete their maturation before migrating to other peripheral lymphoid organs?

spleen Signup and view all the answers

What is the fate of immature B cells that leave the bone marrow?

Most will not survive to become fully mature B cells Signup and view all the answers

Which subset of B cells arise from fetal liver-derived stem cells and are found in peritoneal and pleural cavity fluid?

B-1 lineage Signup and view all the answers

Where are follicular B cells mainly located?

in the spleen and lymph nodes Signup and view all the answers

What is the role of subcapsular sinus macrophages in B cell activation?

capture large microbes and antigen-antibody complexes and deliver them to follicles Signup and view all the answers

How are antigens in immune complexes delivered to follicular B cells?

via binding to complement receptor CR2 on marginal zone B cells Signup and view all the answers

What is the role of Activation-induced cytidine deaminase (AID) in B cell function?

AID is the initiator of mutations in somatic hypermutation and class switching. Signup and view all the answers

What is affinity maturation and how does it occur in a T-dependent humoral response?

Affinity maturation leads to increased antibody affinity for an antigen through somatic hypermutation and selective survival of high-affinity B cells. Signup and view all the answers

Explain the process of class switching in B cells.

Class switching involves recombining the Ig heavy chain DNA to change the antibody's heavy chain class. Signup and view all the answers

What is somatic hypermutation and where does it predominantly occur?

Somatic hypermutation is the generation of point mutations in the variable region of expressed immunoglobulin genes in response to antigens. Signup and view all the answers

How does the process of heavy chain isotype switching contribute to antibody diversity?

Heavy chain isotype switching allows B cells to produce antibodies with heavy chains of different classes, increasing antibody diversity. Signup and view all the answers

What is the function of FDCs in relation to class II MHC molecules?

FDCs do not express class II MHC molecules. Signup and view all the answers

How does the recombination of VDJ exon and C region DNA contribute to B cell function?

Recombination of VDJ exon and C region DNA allows for the production of antibodies with diverse variable regions and constant regions. Signup and view all the answers

Explain the significance of selective survival of B cells with high-affinity antibodies in affinity maturation.

Selective survival leads to the persistence of B cells producing antibodies with the highest affinities for antigens. Signup and view all the answers

Where does Ig heavy chain isotype switching occur in the B cell development pathway?

Ig heavy chain isotype switching occurs in T-dependent responses during B cell activation. Signup and view all the answers

What initiates the generation of point mutations in the variable region of expressed immunoglobulin genes?

Point mutations in the variable region are initiated by the activation-induced cytidine deaminase (AID). Signup and view all the answers