CHARACTERIZATION OF AN IL-6-LIKE MOLECULE FROM AN ECHINODERM (ASTERIAS-FORBESI)

Our previous studies have demonstrated the presence of two of the thre e vertebrate inflammatory cytokines in invertebrates, namely, interleu kin (IL)-1 and tumour necrosis factor (TNF), We studied the coelomic f luid of the echinoderm, Asterias forbesi, to determine whether it cont ained the third inflammatory cytokine, IL-6, Coelomic fluids were conc entrated and then fractionated by a combination of gel sieve chromatog raphy and preparative isoelectric focusing, The M(r) observed for the invertebrate IL-6-like molecule was approximate to 30 000 and the pI w as 5.5, Western blot analysis using a polyclonal rabbit antiserum to h uman IL-6 detected a band at approximate to 30 000 Da, The invertebrat e IL-6 was inhibited by an antiserum to human IL-6 when used in the B9 assay Finally, the coelomocytes were found to be capable of releasing the IL-6-like molecule as early as 12 h following stimulation by LPS, These results, together with our other data, show that echinoderms po ssess correlates of all three vertebrate inflammatory cytokines. (C) 1 996 Academic Press Limited