Species-specific dissociation into single cells of live sea urchin embryos by Fab against membrane components of Paracentrotus lividus and Arbacia lixula.

The species and stage specificities of membrane components active in promoting reaggregation of cells dissociated from embryos of the two Mediterranean sea urchin species Paracentrotus lividus and Arbacia lixula have been examined. Membrane proteins extracted with butanol either from purified membranes or from dissociated cells without significant reduction of viability promoted reaggregation of both the homologous and heterologous species. Extracts from plutei and blastulae were equally effective in promoting reaggregation of blastula cells. By contrast, Fab's prepared from IgG raised against these extracts or purified membranes are strictly species specific because they prevent reaggregation of cells and actively dissociate live embryos of only the homologous species. No corresponding stage specificity of the Fab was observed: Fab against extracts from blastula embryos also caused dissociation of plutei. Antigenic analysis of the extracts by the Ouchterlony test revealed the presence of components specific for each species as well as others common to both.