Chapter 10

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Chapter 10
B-Cell Development
Dr. Capers
Kindt • Goldsby • Osborne
Kuby IMMUNOLOGY
Sixth Edition
Chapter 11
B-Cell Generation, Activation,
and Differentiation
Copyright © 2007 by W. H. Freeman and Company
Development of B cells

In many vertebrates, including humans and mice, B
cells generate in bone marrow
 Antigen-independent phase
 Ig-gene rearrangement to create antigen-specificity
 In the fetus, this happens in the liver

Immature B cell bearing IgM on membrane leaves
bone marrow
 Matures to express both IgM and IgD with single antigen
specificity
 NAÏVE B cells – have not encountered antigen

Encounter antigen in secondary lymphoid tissue
 Differentiate into plasma cells and memory cells
 Class switching
B cell development starts
in bone marrow and
completes in periphery
B cell development








Hematopoietic Stem Cell can develop into Common
Lymphoid Progenitor cell (CLP)
CLP can develop into Pro-B cell
Pro-B cell develops into Pre-B cell
Pre-B cell develops into immature B cell
Immature B cells leave bone marrow
Travels to spleen where it matures
Mature B cell leaves spleen
○ Expressing high IgD and some IgM on surface
Migrate to lymphoid follicles
○
Class switching occurs after contact with antigen

Bone marrow
 Pro-B cell → precursor
B cell
 Stromal cell in bone
marrow secrete IL-7
that help development
into immature B cells

Pro-B Cell
○ Heavy chain rearrangement

Pre-B cell
○ Light chain rearrangement

Immature B cell
○ Is now committed to antigenic specificity and
produces IgM
○ B cell not fully functional, must first express
both IgM AND IgD on membrane

In mice, 90% of B cells produced
everyday die without ever leaving bone
marrow
○ Negative selection due to cells that express
auto-antibodies against self antigen in the
marrow
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