Elements of angiotensin system are involved in leeches and mollusks immuneresponse modulation

We present immunocytochemical, biochemical and cellular evidences for the p resence of a renin-angiotensin system (RAS) in coelomocytes of invertebrate s (leech, Theromyzon tessulatum and mollusk Mytilus edulis). Leech coelomoc ytes are immunoreactive to polyclonal antisera raised against the T. tessul atum angiotensin-converting enzyme (ACE) and leech brain angiotensin Il (AI I) and a commercial anti-ATI receptor. Biochemically, renin, ACE- and ATI-l ike receptor were identified in the leech immune cells. We further demonstr ate that leech All (10(-6) M) alone does not initiate nitric oxide (NO) rel ease in invertebrate immunocytes but does only after pre-exposing, the cell s to IL-1 (15.9 +/- 2.6 nM; P < 0.005 vs. 1.1 nM when All is added alone). Similar results were, obtained with human leukocytes (14.5 +/- 2.7 nM; P < 0.005 IL-1 + AII vs. 0.9 nM when All is added alone). Then, an immunocytoch emical study performed at the structural and ultrastructural levels confirm ed the presence in same immune cells all the molecules of the renin-angiote nsin system (RAS) in leeches as epitopes to IL-1-like protein and IL-1-like receptor. This is the first report in invertebrates and of a co-action bet ween cytokines like substances and neuropeptides in an immune process and t he involvement of the RAS in modulation of the immune response. (C) 2001 El sevier Science BY All rights reserved.