H. HogenEsch, 2004
Development of B lymphocytes
Parham, Chapter 4
H. HogenEsch, 2004
B cell development
Fig. 4.2
H. HogenEsch, 2004
antigen-independent
stem cell pre-B cell(chain +)
immature B cell(IgM +)
mature B cell(IgM , IgD +)
IgG
IgAIgE
IgM
antigen-dependent
isotype switching
H. HogenEsch, 2004
Pre-B cell pre-B cell receptor = + surrogate light
chain
H. HogenEsch, 2004
B cell development in bone marrow
Bone marrow stromal cells
H. HogenEsch, 2004
Ig gene rearrangements – allelic exclusion
Fig. 4.6
H. HogenEsch, 2004
Sequential L chain gene segment rearrangements
H. HogenEsch, 2004
Immunoglobulin gene expression during B cell development
H. HogenEsch, 2004
Selection of immature B cells
Fig. 4.13
H. HogenEsch, 2004
Receptor editing
H. HogenEsch, 2004
B-1 cells vs. B-2 cells
H. HogenEsch, 2004
B-1 cells vs. B-2 cells (cont’d)
H. HogenEsch, 2004
X-linked agammaglobulinemia• Recurrent infections of extracellular bacteria
• Recessive, X-linked
• Defect in Bruton’s 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
H. HogenEsch, 2004
Circulation of naïve B cells
Fig. 4.15
H. HogenEsch, 2004
Further development of mature B cells
H. HogenEsch, 2004
Effect of specific antigen on B cell migration and differentiation
Fig. 4.16
H. HogenEsch, 2004
Histology of the lymph node cortex
M = mantle zoneGC = germinal center
• D = dark zone • L = light zone
H. HogenEsch, 2004
B cell life cycle
IgM
Naïve B cell
Ag
isotype switchinggerminalcenter
apoptosis
medulla
paracortex
bone marrow
IgG
memoryB cell
days - weeks
apoptosis
5 days
months
H. HogenEsch, 2004
B cell tumors
H. HogenEsch, 2004
Burkitt’s lymphoma