immunology of infectious and parasitic diseases - XXXVII Congress ...

FAS/FASL AND TRAIL CAUSE APOPTOSIS OF T CELL CD4 AND CD8 IN
CANINE NATURALLY INFECTED VISCERAL LEISHMANIASIS
KATHLENN LIEZBETH OLIVEIRA SILVA (PG) 1 ; BRUNA BRITO OLIVEIRA
(IC) 1 ; JULIANA PEROSSO (PG) 1 ; LARISSA MARTINS MELO (PG) 1 ; VALÉRIA
MARÇAL FÉLIX DE LIMA 1 .
1-Laboratory of cellular immunology, Faculty of Veterinary Medicine – FMVA –
UNESP - “Júlio de Mesquita Filho” - Araçatuba/SP
Introduction: Visceral leishmaniasis (VL) is an emerging disease caused by L.
chagasi in Brazil. The dogs are the main reservoirs urban of the disease. In
symptomatic dogs the VL is characterized by immunosuppression of cellular
immune response with the parasites wide dissemination, mainly in the spleen,
liver and bone marrow, and T cell apoptosis was observed. The molecules
involved in the apoptosis are the FAS/FASL and TRAIL. However, the role of
these receptors in canine visceral leishmaniasis is not yet clear. The objective
of this research was to evaluate the rate of apoptosis in CD4 and CD8 T cell
from spleen and peripheral blood of dogs infected by L. chagasi, investigate the
expression of cell surface molecules FAS / FASL and TRAIL, as well as to
identify whether apoptosis is dependent cell contact. Methods and Results:
Mononuclear cells from spleen and peripheral blood of 15 dogs with VL and 5
healthy dogs were used to assess the rate of apoptosis in T lymphocytes CD4
and CD8 and the expression the FAS/FASL and TRAIL. The cell staining for
CD4 and CD8 was performed using monoclonal antibodies conjugated to
fluorochromes; apoptosis was measured using the kit Guava Nexin ® Assay.
The FAS, FAS-L and TRAIL were measured using monoclonal antibodies
conjugated to fluorochromes. To check if the apoptosis in T cell is dependent on
cell contact, macrophages were infected with 5x10 6 promastigotes of L. chagasi
at the bottom of a culture plate and the upper part comprises a transwell was
added cell from healthy dogs and apoptosis rate measured. Data were acquired
in the cytometer EasyCyteMini and analyzed with the Cytosoft ® software. The
results were compared using the Mann-Whitney test, with significance level of
5%. It was observed a increased of apoptosis in CD4+ and CD8+ T cell from
spleen and peripheral blood of infected dog compared to healthy. The FAS
increase in CD4+ T cell from peripheral blood and also increase CD8 T cell from
spleen in infected dog, while FAS-L and TRAIL decrease in CD4 and CD8 T cell
from PBMC and spleen from infected dogs compared to healthy ones. The data
from transwell plate suggests that the apoptosis in CD4+T cell depends on cell
contact. Conclusions: The FAS and FASL in T cell from infected dogs are
involved in the apoptosis; this knowledge may allow future therapeutic
interventions in order to reduce the depletion of lymphocytes, thereby
increasing the ability of defense.
Financial Support: FAPESP