Nectadrin, the heat-stable antigen, is a cell adhesion molecule

Area of Science:

• Cell Biology
• Immunology
• Glycobiology

Background:

• Nectadrin is a cell surface glycoprotein recognized by monoclonal antibody 79.
• It is immunologically identical to the heat-stable antigen (HSA).
• Nectadrin has a small polypeptide core and high carbohydrate content.

Purpose of the Study:

• To investigate the function of nectadrin.
• To determine if nectadrin acts as a cell adhesion molecule.
• To characterize the molecular forms and aggregation properties of nectadrin.

Main Methods:

• Immunocytological studies on B-lymphocytes, neuroblastoma, and cerebellar cells.
• Inhibition assays using purified nectadrin and monoclonal antibodies.
• Purification and characterization of nectadrin from a mouse lymphoma cell line.
• Aggregation assays with latex beads coated with purified nectadrin.

Main Results:

• Nectadrin is preferentially expressed at sites of cell-cell contact.
• Monoclonal antibody 79 and purified nectadrin inhibited B-lymphocyte aggregation by 70%.
• Nectadrin exists in two forms (40-60 kD and 23-30 kD), with the larger form more potent in mediating aggregation.
• Nectadrin exhibits self-binding properties, suggesting a role in cell adhesion mediated by its glycan structures.

Conclusions:

• Nectadrin functions as a cell adhesion molecule, potentially through its extensive glycan structures.
• It is a novel type of self-binding molecule involved in cell-cell interactions.
• The different molecular forms of nectadrin may have distinct roles in adhesion processes.