ADHESIVE HIERARCHY INVOLVING THE CELL-ADHESION MOLECULES L1, CD24, AND ALPHA-6 INTEGRIN IN MURINE NEUROBLASTOMA N2A CELLS

The aggregation rate of resuspended neuroblastoma N2A cells depends on the density of the cells in culture prior to their resuspension: isol ated, fast growing cells have a weak tendency to aggregate whereas con fluent, slowly growing cells reaggregate very strongly, L1 antibody 55 7 strongly inhibited the slow aggregation of isolated, fast growing ce lls but not the reaggregation of confluent cells, CD24 (nectadrin) ant ibodies did not affect the aggregation of isolated or confluent cells bat stimulated the aggregation of subconfluent cells, In all stages ag gregation was not inhibited when antibody 557 was used together with C D24 antibodies at 37 degrees C in the presence of divalent cations, EA -1 antibody to alpha 6 integrin chain stimulated the aggregation of su bconfluent cells but inhibited the reaggregation of confluent cells, T herefore, L1 appears to be an early recognition molecule mediating wea k primary adhesion, CD24 appears to participate in activating secondar y adhesion mechanisms during primary adhesion, possibly in cooperation with L1, and alpha 6 integrin seems to serve as a secondary, strong a dhesion molecule that in early adhesion phases also mediates the activ ation of itself or of other adhesion mechanisms, These results indicat e that neural cells might employ a strategy of adhesion cascade in est ablishing stable contacts. (C) 1995 Academic Press, Inc.