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