A novel monoclonal antibody against carbohydrates of L1 cell adhesion molecule causes an influx of calcium in cultured cortical neurons.

We have studied the function of carbohydrates of the L1 molecule, a member of the immunoglobulin superfamily of adhesion molecules, using a novel monoclonal antibody, mAb-L1(2E12), against L1 molecule. This antibody was specific for the 200 kDa component of mouse L1 molecule and its epitope was N-linked for complex-type oligosaccharides. The mAb-L1(2E12) was found to induce a rise in intracellular Ca2+ concentration ([Ca2+]i) in cultured mouse embryonic cortical neurons. The rise in [Ca2+]i was dependent on the concentrations of mAb-L1(2E12). The rise seemed to be due to an influx of extracellular Ca2+ as EGTA treatment abolished it. Both cadmium and nifedipine blocked the effect of mAb-L1(2E12), suggesting the Ca2+ influx was through voltage-operated Ca2+ channels, particularly L-type Ca2+ channels. These results provide an important insight for understanding the mechanisms by which oligosaccharides of the L1 molecule influence various functions of neural cells.