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

Leishmania amazonensis INCREASES ECTONUCLEOTIDASES
EXPRESSION IN LYMPH NODE DENDRITIC CELLS AND T REG CELLS
POPULATIONS IN LESION SITES
AMANDA BRAGA DE FIGUEIREDO; PRISCILA MARTINS DE SOUZA, TIAGO
DONATELLI SERAFIM; LUÍS CARLOS CROCCO AFONSO
Laboratório de Imunoparasitologia, Departamento de Ciências Biológicas, ICEB
/ NUPEB, Universidade Federal de Ouro Preto. Ouro Preto, Minas Gerais,
Brazil.
Introduction: Leishmania infections can result in a wide spectrum of clinical
manifestations, and the outcome of disease is determined by parasite species
and the host immune response. Dendritic cells (DC) play an essential role in the
modulation of immune response and T reg cells are important in
immunosuppressive response, including during Leishmania infection.
Extracellular-ATP exhibits pro-inflammatory properties whereas adenosine is an
important anti-inflammatory mediator. Our objective was to investigate the DC
activation, the ectonucleotidases expression in these cells and the generation of
T reg cells after Leishmania infection. Methods and Results: C57BL/6J mice
were inoculated on ears with 1 x 10 5 CFSE-labelled metacyclic promastigotes of
L. amazonensis, L. braziliensis or L. major. Draining lymph nodes and ears
were isolated after 20 h, 1 and 3 weeks and cells were stained and analyzed by
flow cytometry. After 20 h of infection with L. amazonensis, L. braziliensis or L.
major, approximately 12% of lymph node cells were found to be CD11c + and of
these CD11c + cells 10% were infected. The expression of MHCII, CD86 and
CD40 was significantly higher in lymph node infected-DC, regardless of the
strain of Leishmania used. Interestingly, the infection increases
ectonucleotidases expression in DC and at least 50% of infected cells coexpressed
CD39 and CD73, independent of the parasite species used. L.
amazonensis, L. braziliensis and L. major decrease the percentage of T reg
cells (CD4+CD25+Foxp3+ cells) in draining lymph nodes after 1 or 3 weeks of
infection, but only L. amazonensis increases the percentage of these cells in
lesion sites after 3 weeks of infection. Conclusion: In conclusion, L.
amazonensis increases ectonucleotidases expression in lymph node DC and T
reg cells populations in lesion sites.