In vitro binding and survival assays of Leishmania parasites to peripherical blood monocytes and monocyte-derived macrophages isolated from dogs naturally and experimentally infected with Leishmania (Leishmania) chagasi.
BACKGROUND
There are a few works considering the characterization of canine monocyte-derived macrophages as well as a standardized procedure for isolation, culture, and infection of these cells with Leishmania. We have performed several modifications in order to improve the canine monocyte-derived macrophage cultures. In addition, we have done a comparative study between monocytes and monocyte-derived macrophages from dogs naturally and experimentally infected with L. chagasi.


RESULTS
In the presence of exogenous serum, opsonized Leishmania promastigotes binds better to monocytes/macrophages than without serum. Otherwise, this binding occurs due to the strict correlation between the opsonized biologic particles with the third receptor of the complement (CR3-CD11b/CD18). In fact, our assays with CD11b confirmed the importance of this receptor for canine cells and the L. chagasi experimental system. Moreover, monocytes obtained from naturally infected dogs have shown a higher number of monocytes bounded to promastigotes. The experimental results regarding survival have shown that promastigote forms of opsonized L. chagasi were more infective, because we found higher numbers of promastigotes bound to the different cells. As a consequence, after forty-eight hours of binding, higher numbers of amastigotes appeared inside monocyte-macrophages.


CONCLUSIONS
These studies have given support to continue comparative studies involving canine monocytes, monocyte-derived macrophages and peritoneal macrophages. Since we have standardized the canine cell culture, we are looking forward to determining the phenotypic properties of these cells before and after L. chagasi infection using flow cytometry.
Sampaio
Weverton M
WM
Departamento de Patologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil. godsamp2003@yahoo.com.br
Moura
Eliane P
EP
Arruda
Felipe C S
FC
Ribeiro
Raul R
RR
Alves
Cíntia F
CF
Melo
Ferdinan A
FA
Fernandes
Ana Paula S M
AP
Michalick
Marilene S M
MS
Melo
Maria N
MN
Tafuri
Washington L
WL
Tafuri
Wagner L
WL
D000818:Animals; D004283:Dog Diseases / Q000378:metabolism / Q000469:parasitology*; D004285:Dogs; D005260:Female; D005434:Flow Cytometry / Q000662:veterinary; D018314:Leishmania infantum / Q000378:metabolism*; D007898:Leishmaniasis, Visceral / Q000469:parasitology / Q000662:veterinary*; D008264:Macrophages / Q000378:metabolism / Q000469:parasitology; D017737:Macrophages, Peritoneal / Q000378:metabolism / Q000469:parasitology; D008297:Male; D009000:Monocytes / Q000378:metabolism / Q000469:parasitology*; D016019:Survival Analysis