Development of B lymphocytes

What happens in phase 1?

Generation of diverse B cell receptors in bone marrow

What is phase 1 known as

Repertoire assembly

What happens in Phase 2

Alteration, elimination, or inactivation of autoreactive B cell receptors

What is phase 2 known as

Negative selection

What happens in phase 3

A fraction of immature B cells are promoted to become mature in the secondary lymphatic tissue

What is phase 3 known as

Positive selection

What is the first step in B cell development starting with an early pro B cell?

Rearrangement of heavy chain

After cell forms pre-B cell-receptor, and passes _____ checkpoint, what is the next step ?

Passing the 1st checkpoint, the cell will go through Light chain rearrangement.

What happens if no Pre-B cell-receptor is made, what happens to the cell? What checkpoint did it not pass?

Apoptosis. It did not pass the 1st checkpoint.

After B cell goes through light chain rearrangement, it must pass checkpoint ____ by containing a functional B-Cell-Receptor/having quality light chain rearrangement

B cell passes Checkpoint 2 if it has a BCR and Ig-alpha + Ig-beta

What happens if the B cell does not have quality light chain rearrangement or has no BCR? What checkpoint is it not passing?

It is not passing checkpoint 2 and it is going to go through apoptosis

If the cell passes both checkpoints, what is the cell now?

Immature B cell

When can non-productive rearrangement occur?

If the open reading frame is disrupted by frame shit for stop codon insertion.

If a cell passes checkpoint 1, it will go through what?

Light chain rearrangement

B cells that leave the bone marrow and enter circulation express ____ (Ig) on their surface

IgM

B cells that enter a primary lymphoid follicle express both ____ and ____ (Igs) on their surface

IgM and IgD

Self reactive B cells are selected against before leaving the bone marrow. What is this called. (Two terms_

Negative selection and central tolerance

Some self-reactive B cells can be rescued by receptor editing. This requires the cell to reexpress _____ and re-do _____

Re-express RAG genes and re-do light chain rearrangement

Autoreactive B cells that do leave the bone marrow are typically contained by ________.

Peripheral tolerance

What is peripheral tolerance?

Induction of the cells into a state of nonresponsivness “anergy”

Interactions with _____ and ______ drives the maturation of immature B cells

Follicular dendritic cells and cytokines.