375 JPP 2005, 57: 375–381 ß 2005 The Authors Received July 7, 2004 Accepted November 24, 2004 DOI 10.1211/0022357055579 ISSN 0022-3573 Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceara ´ , Brazil, Cel Nunes de Melo, 1127, 60430–270, Fortaleza-Ceara ´ -Brasil V. B. M. Alencar, N. M. N. Alencar, G. A. C. Brito, R. A. Ribeiro Mestrado em Cie ˆ ncias Fisiolo ´ gicas, Universidade Estadual do Ceara ´, Fortaleza, Brasil M. S. Assreuy, A. V. P. Meireles, M. R. L. Mota BioMol-Lab – Departamento de Bioquı ´mica, Universidade Federal do Ceara ´ , Brazil, C.P. 6043, 60.455-970, Fortaleza-Ceara ´ -Brasil B. S. Cavada, J. B. Cajazeiras, K. S. Araga ˜o, L. I. M. M. Silva BioMol-Lab, Faculdade de Medicina, Universidade Federal do Ceara ´ , Sobral, Brazil, Av. Geraldo Rangel, 62041-180 Sobral-Ce, Brazil V. P. T. Pinto BioMar-Lab, Departamento de Engenharia de Pesca, Universidade Federal do Ceara ´, Brasil, C.P. 6043, 60.455-970, Fortaleza-Ceara ´ -Brasil A. H. Sampaio, C. S. Nagano Laboratoire de Chimie Biologique et Unite ´ Mixte de Recherche N 0 8576 du CNRS, Universite ´ des Sciences et Technologies de Lille, 59655, Villeneuve d’Ascq, France H. Debray Correspondence: B. S. Cavada, BioMol-Lab/UFC. C.P. 6043, 60.455-970, Fortaleza-Ceara ´- Brasil. E-mail: bscavada@ufc.br Funding and acknowledgement: This work was supported by grants from Conselho Nacional de Desenvolvimento Cientı ´fico e Tecnolo ´ gico (CNPq), Coordenac ¸a ˜o de Aperfeic ¸ oamento de Pessoal de Nı ´vel Superior (CAPES), Financiadora de Estudos e Projetos (FINEP), International Foundation for Science (IFS), and Fundac ¸a ˜o Cearense de Amparo a ` Pesquisa (FUNCAP). R. A. Ribeiro, A. H. Sampaio and B. S. Cavavada are senior investigators from CNPq/Brazil. Lectin of Pisum arvense seeds induces in-vivo and in-vitro neutrophil migration V. B. M. Alencar, A. M. S. Assreuy, N. M. N. Alencar, A. V. P. Meireles, M. R. L. Mota, K. S. Araga ˜ o, J. B. Cajazeiras, C. S. Nagano, G. A. C. Brito, L. I. M. M. Silva, V. P. T. Pinto, A. H. Sampaio, H. Debray, B. S. Cavada and R. A. Ribeiro Abstract PAL is a glucose/mannose-specific lectin isolated from Pisum arvense seeds. Previously, we demon- strated the capacity of other leguminous lectins to induce oedema formation and neutrophil stimulation. To investigate the potential pro-inflammatory activity of PAL, we have studied its ability to induce neutrophil migration into peritoneal cavities of rats and neutrophil chemotaxis in-vitro. The role of resident cells and sugar residues on PAL activity was analysed. PAL or saline (control) were administered intraperitoneally to rats, and total and differential leucocyte (macrophages, neutro- phils and mast cells) counts were performed. The role of resident cells on the PAL effect was evaluated using three strategies: reducing the total resident cell population by lavage of rat cavities with saline; increasing macrophage population by treating animals with thioglycolate; and deplet- ing mast cell population by subchronic treatment of rats with compound 48/80. PAL induced in-vitro and in-vivo neutrophil migration. In-vivo, PAL (50, 100, 200 and 300 g) significantly (P < 0.05) and dose-dependently increased neutrophil migration by 600, 740, 900 and 940%, respectively, showing maximal effect 4 h after injection. PAL induced mononuclear cell migration. The neutrophil stimu- latory effect of PAL was potentiated in animals treated with both thioglycolate and compound 48/ 80. The indirect lectin chemotactic effect was shown in rats injected with supernatant from cultured macrophages stimulated by PAL. In conclusion, PAL was shown to exhibit in-vivo and in-vitro pro- inflammatory activity. The in-vivo effect seemed to occur by a dual mechanism that was indepen- dent, but also dependent, on resident cells. Introduction Neutrophil migration from the blood into affected tissues is the hallmark of acute inflam- matory reactions. The recruitment of these cells involves a complex and multi-mediated process which is possible by intercellular signalling (McEver 1992). This mechanism involves interaction of endothelial cells and neutrophils via recognition between lectins and adhesion molecules expressed on these cell surfaces (Rabinowich 1996; Kieda 1998). Constitutively, cells express adhesion molecules (Kieda 1998), but under inflammatory processes or other pathologic conditions these molecules are over expressed (Barnes & Adcock 1997). It seems clear that this over expression is mediated by pro-inflammatory cytokines released by resident cells (macrophages, mast cells and endothelial cells), acti- vated by bacterial products (lipopolysaccharide), pathogen proteins and cytokines (Hogan & Schwartz 1997; Ishii et al 1997). After activation, a coordinated expression of multiple inflammatory genes takes place, including cytokines and neutrophil chemoattractants, such as interleukin 8 (IL-8), macrophage inflammatory protein-1 and -2 (MIP-1, MIP-2), cytokine-induced neutrophil chemoattractant (CINC), eotaxin, enzymes and adhesion molecules (Driscoll et al 1993; Barnes & Adcock 1997; Ishii et al 1997). Lectins are (glyco)proteins of non-immune origin that interact reversibly and specifically with carbohydrates (Peumans & van Damme 1995). They are widely distributed in nature, and amongst the plant kingdom. The legume lectins are a large