title: Isolation and characterization of sea star factor.
abstract: Sea star factor (SSF) harvested from the echinoderm Asterias forbesi celomocytes is a potent inhibitor of the primary immune response to T-dependent antigens and also suppresses concanavalin-A-induced mitogenesis. We have isolated and purified a basic protein from this source which has a molecular weight of approximately 38, 000 daltons and is responsible for these biological activities. After complete reduction, SSF was shown to be composed of a single pair of heavy and light chains. Preincubation of spleen cells with concanavalin A does not inhibit binding of SSF; however, specific binding can be inhibited by preincubation with unlabeled SSF. These data suggest that the binding site for SSF is not the same as that for concanavalin A.
mesh_terms: D000478:Alkylation; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001665:Binding Sites; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D007128:Immunoglobulin Fragments / Q000032:analysis / Q000302:isolation & purification*; D007143:Immunoglobulin Heavy Chains / Q000032:analysis / Q000302:isolation & purification; D007147:Immunoglobulin Light Chains / Q000032:analysis / Q000302:isolation & purification; D008970:Molecular Weight; D013048:Specimen Handling; D013215:Starfish / Q000276:immunology*
chemical_list: D000596:Amino Acids; D007128:Immunoglobulin Fragments; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains