Arginase activity in lymph node in canine visceral Leishmaniasis

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 the 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 an impaired function of T cells, and production of NO by macrophages. Thus intends to verify if the naturally infected increase of parasite load is correlated with arginase activity. (AU)