title: The echinoid immune system revisited.
authors.forename: E L
authors.initials: EL
authors.lastname: Cooper
mesh_terms: D000818:Animals; D004447:Echinodermata / Q000276:immunology*; D007156:Immunologic Memory; D008954:Models, Biological; D012617:Sea Urchins / Q000276:immunology; D014184:Transplantation, Homologous