Early stages of B cells
development are dependent on bone marrow stromal cells and achieve maturity in
peripheral lymphoid organs
Stromal cells:
(1) Provide specific contacts
with B cell progenitors: Adhesion molecule VCAM-1 and CAMs on stromaè promote
the binding of the receptor tyrosine kinase Kit (CD117) on B cell to stem-cell
factor (SCF: stromal membrane bound cytokine) è induces
proliferation
(2) Provide soluble factors that control lymphocyte proliferation and
further development
: IL7 to IL7 receptor (in mice), chemokine CXCL12, steroid hormones (limit production of B
cells)