Veterinary Parasitology 205 (2014) 417–423 Contents lists available at ScienceDirect Veterinary Parasitology jo u r nal homep age: www.elsevier.com/locate/vetpar Alteration of sFAS and sFAS ligand expression during canine visceral leishmaniosis Juliana Perosso, Kathlenn Liezbeth Oliveira Silva, Stefáni Íris de Souza Ferreira, Saulo Vinícius Avanc¸ o, Paulo Sérgio Patto dos Santos, Flávia de Rezende Eugênio, Breno Fernando Martins de Almeida, Valéria Marc¸ al Felix de Lima ∗ Department of Clinical Care, Surgery and Animal Reproduction, Laboratory of Cellular Immunology, School of Veterinary Science of the São Paulo State University (Faculdade de Medicina Veterinária da Universidade Estadual Paulista “Júlio de Mesquita Filho”, FMVA/UNESP), Rua Clóvis Pestana, 793, Arac¸ atuba, São Paulo, CEP 16050-680, Brazil a r t i c l e i n f o Article history: Received 1 January 2014 Received in revised form 2 September 2014 Accepted 7 September 2014 Keywords: Cell death FAS-associated death domain protein FAS ligand protein Leishmania infantum Leishmaniosis TRAIL (TNF-related apoptosis-inducing ligand) a b s t r a c t Visceral leishmaniosis (VL) is caused by intracellular parasites of the genus Leishmania that affect humans and several animal species. Dogs are one of the main urban reservoirs of Leish- mania infantum and play a central role in the transmission cycle to humans via sandflies. CD3+ cells apoptosis is involved in the immune response in VL. Dysregulation of apopto- sis has been implicated in various disease states. An important regulator of apoptosis is the FAS-FAS-associated death domain protein (cluster of differentiation 95 – CD95) and FASL-FAS ligand protein (cluster of differentiation 178 – CD178) system involved in the down-regulation of immune reactions and in T cell-mediated cytotoxicity. FAS is a mem- ber of the tumor necrosis factor (TNF) receptor super family, which can be expressed in transmembrane or soluble forms. The soluble levels of FAS (sFAS), FASL (sFASL) and active Caspase-3, this last related to apoptotic cascade, were investigated in the spleen of 19 symp- tomatic dogs presenting moderate VL and 6 healthy dogs, determined by ELISA assay. The splenic parasite load was determined by real-time PCR monitoring of amplification of the intergenic internal transcribed spacer (ITS1) gene of parasite rRNA. sFAS levels were lower (p < 0.05). sFASL and active Caspase-3 levels were higher (p < 0.05) in dogs with VL compared with controls. Negative correlation was observed between parasite burden and sFASL lev- els. The increase in sFASL could be related to the mechanism involved in the elimination of the parasite. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Leishmaniosis occur in more than 100 countries, from warm temperate through subtropical to tropical climates (Ashford et al., 1992). Visceral leishmaniosis (VL) is a severe ∗ Corresponding author. Tel.: +55 18 3636 1422. E-mail address: vmflima@fmva.unesp.br (V.M.F. de Lima). chronic disease that is potentially fatal to humans, caused by different species of the genus Leishmania (Desjeux, 2004). Brazil is currently facing the expansion and urban- ization of VL. The transmission cycle, which previously occurred in sylvatic and rural areas, is also currently developing in urban centers, creating favorable condi- tions for the emergence and reemergence of diseases (Desjeux, 2004). In association with these factors, environ- mental and climate changes are occurring, the vector is http://dx.doi.org/10.1016/j.vetpar.2014.09.006 0304-4017/© 2014 Elsevier B.V. All rights reserved.