Heparin-induced aggregation of lymphoid cells

Area of Science:

• Cell biology
• Biochemistry
• Immunology

Background:

• Cell-to-cell adhesion is fundamental for tissue formation and immune responses.
• Understanding the molecular mechanisms of cell aggregation is key to various biological processes.

Purpose of the Study:

• To investigate the role of carbohydrates in mediating cell-to-cell adhesion.
• To identify specific carbohydrates that induce cell aggregation and characterize their binding interactions.

Main Methods:

• Cell aggregation assay using a Coulter Counter to monitor cell loss.
• Binding experiments with radiolabeled heparin (3H-heparin).
• Investigation of environmental factors (pH, ionic strength) on heparin binding and aggregation.

Main Results:

• Heparin and dextran sulfate were the only carbohydrates to induce cell aggregation in lymphoid cells.
• Heparin-induced aggregation was observed in mouse splenocytes and lymphoid cell lines (P388, YAA-CI), but not in fibroblastic cell lines.
• YAA-CI cells bound significant amounts of heparin, indicating a specific interaction.
• Binding affinity (Kd) and aggregation were sensitive to pH and ionic strength, suggesting an ionic interaction.

Conclusions:

• Heparin and dextran sulfate mediate cell aggregation in lymphoid cells through ionic interactions with the cell surface.
• The binding of heparin to YAA-CI cells is specific and influenced by physiological conditions.
• These findings highlight the importance of carbohydrate-protein interactions in cell adhesion.