Lymphoid precursor cells adhere to two different sites on fibronectin

Area of Science:

• Cell Biology
• Immunology
• Biochemistry

Background:

• Cell adhesion to fibronectin is crucial for various biological processes.
• Lymphoid cell differentiation involves dynamic changes in cell surface molecules.
• Fibronectin receptors mediate cell interactions with the extracellular matrix.

Purpose of the Study:

• To investigate the fibronectin receptors expressed by precursor lymphoid cell lines at different differentiation stages.
• To determine if distinct fibronectin-binding domains are recognized by these cells.
• To explore the role of these receptors in B cell maturation and lymphopoiesis.

Main Methods:

• Utilized precursor lymphoid cell lines (Ba F3 and PD 31) with defined differentiation states.
• Employed in vitro adhesion assays to fibronectin and its specific domains.
• Used affinity chromatography with fibronectin domains and antibody precipitation to characterize receptors.

Main Results:

• Ba F3 cells, in germline configuration, bind to the arg-gly-asp domain of fibronectin via a specific receptor.
• B-committed PD 31 cells, undergoing immunoglobulin light-chain gene rearrangement, bind to a different fibronectin domain associated with heparin binding.
• Antibody against a known fibronectin receptor inhibited adhesion and precipitated distinct receptor components (140/70 kD for Ba F3, 140/120 kD for PD 31).

Conclusions:

• Precursor lymphoid cells express distinct fibronectin receptors mediating substrate adhesion.
• Differential expression of fibronectin receptors correlates with B cell differentiation stages.
• These receptors likely play a significant role in normal lymphopoiesis, as evidenced by shared properties with normal lymphoid precursors.