Arginase activity and levels of PGE-2 in lymph node in canine visceral leishmaniasis

• Grant number: 13/14478-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): September 01, 2013
• Effective date (End): August 31, 2014
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: Valéria Marçal Felix de Lima
• Grantee: Ricardo Gardim de Oliveira
• Host Institution: Faculdade de Medicina Veterinária (FMVA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

Visceral Leishmaniasis is a chronic disease and often fatal if left untreated. According to the Department of Epidemiological Surveillance of the State of São Paulo the disease is expanding with a high mortality rate and the Araçatuba region has the largest number of cases in the state. Dogs have epidemiological importance in endemic areas because they are the domestic reservoir of visceral leishmaniasis, also the infected dog is a potent transmitter of the parasite to humans through the sandfly vector (Lutzomyia longipalpis), and because the canine disease is more prevalent than the human disease, canine cases usually precede human cases. The progression of canine infection is accompanied by a failure of cellular immunity to apoptosis of T lymphocytes and production of cytokines which suppress the microbicidal function of macrophages. The suppression of T cells is well documented, however the mechanisms that lead to failure in the immune response are poorly understood. An important element in the regulation of immune responses is arginase 1, an enzyme that appears impaired function of T cells, and production of NO by macrophages. Furthermore arginase activity is stimulated by PGE-2. In experimental models infected by Leishmania donovani the increased production of PGE2 impaired T cell function but no study has evaluated whether suppression of cellular responses in dogs with canine visceral leishmaniasis is related to these molecules. Thus intends to verify if the naturally infected dogs immune cellular immunity failure is related to the increased of PGE2 production and L-arginine metabolism. (AU)