REGULAR ARTICLE Inflamed adult pharynx tissues and swimming larva of Ciona intestinalis share CiTNFα-producing cells Nicolò Parrinello & Aiti Vizzini & Giuseppina Salerno & Maria Antonietta Sanfratello & Matteo Cammarata & Vincenzo Arizza & Mirella Vazzana & Daniela Parrinello Received: 15 February 2010 / Accepted: 6 May 2010 / Published online: 20 June 2010 # Springer-Verlag 2010 Abstract In situ hybridisation and immunohistochemistry analyses have shown that the Ciona intestinalis tumour necrosis factor alpha gene (CiTNFα), which has been previously cloned and sequenced, is expressed either during the inflammatory pharynx response to lipopolysaccharide (LPS) or during the swimming larval phase of development. Granulocytes with large granules and compartment/morula cells are CiTNFα-producing cells in both inflamed pharynx and larvae. Pharynx vessel endothelium also takes part in the inflammatory response. Haemocyte nodules in the vessel lumen or associated with the endothelium suggest the involvement of CiTNFα in recruiting lymphocyte-like cells and promoting the differentiation of inflammatory haemo- cytes. Specific antibodies against a CiTNFα peptide have identified a 43-kDa cell-bound form of the protein. Observa- tions of pharynx histological sections (at 4 and 8 h post-LPS inoculation) from naive and medium-inoculated ascidians have confirmed the CiTNFα-positive tissue response. Larval histological sections and whole-mount preparations have revealed that CiTNFα is expressed by trunk mesenchyme, preoral lobe and tunic cells, indicating CiTNFα-expressing cell immigration events and an ontogenetic role. Keywords Tumour necrosis factor . Pharynx . Inflammation . Haemocytes . Larval development . Innate immunity . Evolution . Ascicia, Ciona intestinalis (Tunicata) Introduction The Ciona intestinalis inflammatory response involves both a cellular and humoral component. Following lipopolysac- charide (LPS) challenge or inoculation of a foreign agent into the ascidian body wall, several inflammatory events are initiated, including haemocyte recruitment into the inflamed tissue (Parrinello 1981; Parrinello et al. 1984; Parrinello and Patricolo 1984), tissue damage (Parrinello et al. 1984, 1990), encapsulation (Parrinello and Patricolo 1984; De Leo et al. 1997), enhancement of serum haemolymph lectins with human interleukin-1α epitopes (Parrinello et al. 2007), proPO system activity (Cammarata et al. 2008) and upregulation of FACIT-type IX-like collagen (Vizzini et al. 2008) and Ciona intestinalis tumour necrosis factor-α (CiTNFα; Parrinello et al. 2008). The vertebrate TNFα cytokine is a type II transmem- brane protein with an extracellular homotrimeric C-terminal domain that shares several conserved features with compo- nents of the TNF superfamily (Magor and Magor 2001; Bodmer et al. 2002). Following LPS stimulation, the membrane form is cleaved and mature TNFα is secreted by a variety of immune cells. TNFα participates in a number of inflammatory responses, including the recruit- ment and activation of inflammatory cells, and plays a pivotal role in cell proliferation, differentiation, cytotoxicity and apoptosis and in the remodelling of the extracellular matrix and the regulation of cell adhesion molecule and integrin expression (Akira et al. 1990; Idriss and Naismith 2000; Goetz et al. 2004; Ordás et al. 2007; Wride and Sanders 1995). Members of the TNF superfamily have also been found to be critically involved in mouse and chicken development (Wride and Sanders 1995), which forms the basis of the “ontogenic inflammation” model (Kohchi et al. 1991, 1994). This work was supported by a research grant from the Italian Ministry of University and Scientific Research (PRIN 2006 to N. Parrinello). N. Parrinello (*) : A. Vizzini : G. Salerno : M. A. Sanfratello : M. Cammarata : V. Arizza : M. Vazzana : D. Parrinello Department of Animal Biology, Laboratory of Marine Immunobiology, University of Palermo, Via Archirafi 18, 90123 Palermo, Italy e-mail: nicpar@unipa.it Cell Tissue Res (2010) 341:299–311 DOI 10.1007/s00441-010-0993-5