Development of B lymphocytes

1
Development of B lymphocytes

• Parham, Chapter 4

2
B cell development
Fig. 4.2
3
antigen-independent
pre-B cell
immature B cell
mature B cell
stem cell
(
m
chain )
(IgM )
(IgM

, IgD )
antigen-dependent
IgM
isotype switching
IgG
IgE
IgA
4
Pre-B cell pre-B cell receptor m surrogate
light chain
5
B cell development in bone marrow
Bone marrow stromal cells
6
Ig gene rearrangements allelic exclusion
Fig. 4.6
7
Sequential L chain gene segment rearrangements
8
Immunoglobulin gene expression during B cell
development
9
Selection of immature B cells
Fig. 4.13
10
Receptor editing
11
B-1 cells vs. B-2 cells
12
B-1 cells vs. B-2 cells (contd)
13
X-linked agammaglobulinemia

• Recurrent infections of extracellular bacteria
• Recessive, X-linked
• Defect in Brutons tyrosine kinase
• Nearly complete absence of circulating
  immunoglobulins
• Reduced number of pre-B cells in bone marrow,
  lack of mature B cells
• Normal thymus and normal number of T cells

14
Circulation of naïve B cells
Fig. 4.15
15
Further development of mature B cells
16
Effect of specific antigen on B cell migration
and differentiation
Fig. 4.16
17
Histology of the lymph node cortex
18
B cell life cycle
days - weeks
Naïve B cell
Ag
5 days
IgM
paracortex
medulla
months
bone marrow
IgG
isotype switching
germinal center
memory B cell
19
B cell tumors
20
Burkitts lymphoma