Caracterização da infecção da linhagem de macrófagos caninos (DH82) por duas espécies de Leishmania: Leishmania amazonensis e Leishmania chagasi

Abstract

Canine leishmaniasis occurs in many countries from both Old and New World. Latin America presents an estimated incidence of millions case of infected dogs, reaching up to 75% of the population in endemic areas. Canine infection by Leishmania chagasi species is the most common, even though the dog may be infected by other Leishmania species, and reports of this fact are ever more often. Most studies use murine macrophages as a model of studying leishmaniasis in vitro. In this study, we characterize the infection of canine DH82 macrophages cell line by L. amazonensis and L. chagasi in order to propose a possible in vitro canine model. Our results demonstrated that the canine DH82 macrophages cell line interacts with promastigotes of both Leishmania species, however L. amazonensis interact more than L. chagasi. Furthermore, we have observed that L. amazonensis is more infective to canine DH82 macrophages than L. chagasi. Specific antibody opsonization facilitates interaction and increases the survival rates of L. chagasi when compared to non-opsonized L. chagasi. The analysis of interaction and infection profile of DH82 and RAW 264.7 macrophages cell lines by L. amazonensis and L. chagasi showed to be similar. Expression analysis of MHC II and CD80 on canine macrophage DH82 surface showed that these cells have a basal expression and that none of the Leishmania species modulate the expression of MHCII, but basal expression of CD80 seems to be increased in the presence of L. amazonensis. In LPS- stimulated cells was observed an increase of CD80 and MHCII expression, however, the parasites do not appear to modulate the expression of both molecules in LPS-stimulated cells. NO and ROS detection in canine DH82 macrophages showed that these cells have basal levels of NO and ROS, and that, after stimulation with LPS, there is an increase of it. The detection of NO and ROS in L. amazonenis or L. chagasi infected macrophages, showed that none of the species induced NO or ROS on basal or LPS-stimulated cells. Despite the differences found among our proposed experimental model and others described in the literature, canine DH82 macrophage cell line may be a possible canine experimental model of infection by Leishmania.