Lecture 8

Question 1

Where do B-1 B cells and B-2 B cells come from?

Answer 1

1: self-renewing and usually found in the peritoneal/pleural cavities
2: from bone marrow
- follicular and marginal zone

Question 2

Where are B-1 B cells antigen-activated? What are the differences of B-1 B cells from B-2 B cells

Answer 2

microbiota in the gut
- limited V segment, less junctional diversity, no TdT

Question 3

Where are MZ B cells found? What differentiates them from FO B cells?

Answer 3

• spleen and lymph nodes
• respond rapidly to blood-borne microbes and differentiate into short-lived IgM secreting plasma cells
• express IgM in the absence of IgD, express high levels of CD21

Question 4

What differentiates FO B cells from MZ B cells?

Answer 4

• express both IgM and D
• migrate between secondary lymph organs and reside in the follicles
• make Th dependent Ab responses to protein antigens
• make high-affinity Abs and memory B cells

Question 5

What kinds of self-Ag can a b cell come in contact with in the bone marrow?

Answer 5

• soluble and membrane bound
• monovalent or multivalent

Question 6

What happens if the immature B cell binds to self Ag?

Answer 6

receptor editing (continues somatic recomb where it left off)

Question 7

What happens if a BCR gets tested with a monovalent self-antigen?

Answer 7

no cross-linking, no signalling– can leave the bone marrow but becomes anergic

Question 8

what is central tolerance?

Answer 8

screening process for self-reactivity and eliminating self-reactive cells in the bone marrow

Question 9

What would happen if bacterial pathogen infected the bone marrow?

Answer 9

B cells that recognized the antigen would undergo apoptosis

Question 10

What is the structure of the spleen?

Answer 10

red pulp, white pulp separated by the marginal zone

Question 11

What is the periarteriolar lymphoid sheath? PALS

Answer 11

zone for the T cells

Question 12

How does an immature B cell become mature?

Answer 12

In the spleen: the immature B cell goes through transitional stage– differentiate between FO B and MZ B
- peripheral tolerance: B cell gets exposed to other self Ag in the PALS
- if it still survives: CXCL13 expression and enter follicle (mature FO B cell)

Question 13

What is BAFF?

Answer 13

B cell activator factor– required for the B cell to stay alive

Question 14

What do FDCs produce?

Answer 14

BAFF, CXCL13