Cell Development

Question 1

Describe the stages of B cell development

Answer 1

maturation - beings in bone marrow and ends in periphery (still naive)
differentiation - begins when a B cell recognizes its specific Ag, ends with the generation of Ag-specific plasma cells and memory B cells

Question 2

Discern the diff markers of B cell development

Answer 2

PRO(genitor) - B cell: most immature form
PRE(cursor) - B cell: V(D)J recombination of both chains is complete and begins to express IgM/D
Immature B cell - develops central tolerance and goes through receptor editing (last chance to citational B cell - leave bone marrow to blood then to spleen
mature B cell - expresses both IgM/D, can’t undergo further V(D)J rearrangement, STILL naive

Question 3

What are the 3 stages of B cell activation?

Answer 3

occurs in secondary lymphoid tissue

1) antigen binding - binding to B cell receptor (binding to antigen)
2) costimulation - T cells stimulate (binding to T cell is TCR and CD40L) (binding on the B cell side if MHC II and CD40)
3) cytokine help - cytokines are used to fully activate

Question 4

Differentiate between primary follicle, secondary follicle, and germinal center

Answer 4

primary follicle - don’t have a germinal center. an antigen is sent towards the area with the T-cells, the t-cell will be dragged back to the primary follicle and stimulation will cause the expansion and replication of the primary follicle, becoming a secondary follicle
secondary follicle - don’t have a germinal center
germinal center - this is where hypermutation, affinity maturation and isotype switching happen

Question 5

What’s the importance and function of plasma cells and memory B cells?

Answer 5

memory B cells response much faster the second time you seen an Ag
2 kids of plasma cells
short lived: 6-10 days, low affinity, stems straight from naive B cells
long lived: months, stems from germinal center, typically in bone marrow, lymph node medulla, or red pulp (secretes IgG, IgA, IgE)

Question 6

Understand the different antibody functions

Answer 6

Aid with clearance and or destruction of antigen
naturalization (blocked attachment, blocked endocytosis, blocked uncoating)
classical complement activation
opsonization (coating of antigen with host protein to trigger phagocytosis)
antibody dependent cell mediated cytotoxicity (occurs when the Ab-coated substance above is too large to be ingested by phagocytosis)