PROPERTIES OF SEA-URCHIN CELOMOCYTE AGGLUTININS

We examined some biological activities of a 200-kDa glycoprotein, refe rred to as Paracentrotus lividus vitellogenin, contained both in the c oelomic fluid and in a subpopulation of coelomocytes called <<colourle ss spherula cells>>. Cell-free coelomic fluid, coelomocyte lysate and supernatant obtained after coelomocyte washings were assayed for hemag glutinating activity. All samples agglutinated rabbit erythrocytes in a calcium-dependent way. The comparison between the electrophoretic pa tterns of erythrocyte lysates, before and after incubation with the co elomic fluid, revealed that a 200-kDa band was obtained from membranes of agglutinated erythrocytes. In addition, polyclonal antibodies agai nst 200-kDa glycoprotein from sea urchin embryos used in Western blot analysis recognized the 200-kDa glycoprotein only when erythrocyte lys ates previously incubated with coelomic fluids were assayed. These res ults suggest that the 200-kDa glycoprotein could be an agglutinin, pre sent in the coelomic fluid and released by coelomocytes during stress conditions.