BIOL 5500 - B Cell Development, Activation and Differentiation

Which checkpoint is checking if the heavy chain was rearranged correctly and the presence of the pre-B-cell receptor is there?

First Checkpoint

Which checkpoint checks if the light chain rearrangement is working and there is a B cell receptor?

Second Checkpoint

What happens if a B cell fails a checkpoint?

Apoptosis

Survival of what cell depends first on the productive rearrangement of the heavy chain?

Pro-B Cells

How many successive attempts can be made at successful rearrangement of the kappa chain?

Five

What cell undergoes negative selection?

Immature B Cell

If what ligates the immature B cell’s IgM and it continues to rearrange light-chain genes?

Self Antigen

What allows the immune B cell more chances to make a non-autoreactive BCR?

Receptor Editing

Receptor Editing doesn’t work work on what chain because of allelic exclusion?

Heavy

True or False: An autoreactive heavy chain makes it through the first checkpoint

True

If new receptors are still self reactive and no further rearrangements are possible, what happens to the immature B Cell?

Apoptosis

To survive and mature, immature B cells must enter what?

Lymphoid Follicles

Interaction with what provides the required maturation and survival signals (positive selection)?

Follicular Dendritic Cells (FDC)

What is the limiting factor in the follicule?

Space

How does antigen get noticed by B cells for activation?

Antigens get taken up by macrophages

What on FDC bind intact virus particles and retain them at the cell surface?

CR1 and CR2

B cells become more activated when their receptors are what by antigens?

Cross-Linked

Signaling cascade is initiated from what domains in Iga and IgB?

ITAM

BCR triggering is greatly enhanced by what?

B cell co-receptor

What makes up the B cell-co receptor?

CD19/CR2/CD81

The B cell co-receptor works best with what, brining together complement receptors and BCR?

Complement-labeled antigens

What requires T cell help for production of antibodies?

T-dependent antigens

What is on T cells for T-dependent B cell activation?

CD40 Ligand

What is on B cells for T-dependent B cell activation?

CD40

CD40/CD40 ligand interaction stimulates the production of what for isotype switching and affinity maturation?

AID

To obtain T cell help, B cell must take up antigen through BCR, process and present peptide antigens via what?

MHC Class II

In T-independent antigens, which one involves a combination of BCR and TLR signals to activate B Cells?

TI-1

In T-independent antigens, which one involves repetitive carbohydrate antigens present at high density on a pathogen surface, leads to extensive BCR cross-linking?

TI-2

TI-1 antigens require contribution from what?

TLR Signaling

In the T cell and B cell activation relay, the T cells gets activated first by what, then help to activate the B cells?

Dendritic Cell

What differentiated B cell migrates to medullary cords or to bone marrow?

Plasma Cells

What differentiated B cell has no cell surface immunoglobulin or MHC Class II?

Plasma Cells

What differentiated B cell is entirely devoted to antibody production?

Plasma Cell

What differentiated B cell are maintained and circulate through the body, ready to rapidly respond upon re-exposure to pathogen?

Memory B cells

What are the sites where somatic hypermutation, affinity maturation, and isotype switching occurs?

Germinal Centers

Where are geminal Centers?

Secondary Follicle

Which cell has the only roll of high-rate Ig Secretion?

Plasma Cell