Nitric oxide production by coelomocytes of Asterias forbesi

Vertebrate mononuclear phagocytes produce a plethora of molecules involved in host defense. Among the most potent are the reactive oxygen and nitrogen intermediates. Coelomocytes from invertebrates subserve many of the same f unctions. In order to determine whether invertebrate phagocytes employ reac tive nitrogen intermediates, we investigated the effect of various nonspeci fic stimulators and invertebrate interleukin (IL)-1 alpha- and beta-like mo lecules on nitric oxide (NO) production. Elevated NO release by stimulated coelomocytes was seen after 24 h. Incubation of stimulated coelomocytes in the presence of arginine analogs inhibited NO release. When invertebrate IL -l-like molecules were added to the coelomocytes, they stimulated the relea se of NO. Western blot analysis using a polyclonal rabbit antiserum to muri ne NO synthase detected a band at approximate to 125 kDa. These data indica te that coelomocytes are capable of producing and releasing NO and that NO is a chemical mediator that has been conserved as a host defense weapon of phagocytes through evolutionary time. (C) 2000 Elsevier Science Ltd. All ri ghts reserved.