Leishmaniasis triggers changes in monocyte subsets in dogs. (VET2P.1048)

Abstract

Abstract Peripheral blood monocytes are the largest group of circulating progenitor cells. Its functions have been revealed through the study of their subpopulations, especially in humans and mice in pathological processes. In Brazil, the parasite L. infantum is the cause of the canine visceral leishmaniasis. This study aimed to characterize subpopulations of peripheral blood monocytes from uninfected or L. infantum naturally infected dogs and compare their phenotypical and functional aspects. Blood samples were collected from uninfected and infected dogs, labeled by antibodies against different surface markers and analyzed by flow cytometry. It was observed two distinct populations according to CD14 expression: a population CD14High, constituting about 90% of the monocytes showing basophilic and horseshoe-shaped nucleus with greater phagocytic capacity, and another CD14Low, constituting about 10% of monocytes, showing less basophilic and kidney-shaped nucleus. The analysis of the other molecules showed different levels of expression between the two populations. In dogs with visceral leishmaniasis no difference in frequency was observed between populations, however there is an increase of CD14+ cells in infected dogs. We also noticed marked reduction of the expression of molecules related to the activation of monocytes, especially in the group of symptomatic dogs, indicating a possible inhibition on the capacity of these cells to control the disease.