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

ACTIVATION PROFILE OF HUMAN DOUBLE-NEGATIVE T CELLS
STIMULATED IN VITRO BY VACCINIA VIRUS AND APEU VIRUS
FERNANDA NOBRE AMARAL VILLANI(1); THAÍS ELOI DA SILVA(1); ERNA
GEESSIEN KROON(2); JAQUELLINE GERMANO DE OLIVEIRA(1); PAULO
CESAR PEREGRINO FERREIRA(2); RODRIGO CORRÊA-OLIVEIRA(1).
(1)Centro de Pesquisas René Rachou, Fiocruz, Belo Horizonte - MG;
(2)Laboratório de Vírus, Departamento de Microbiologia, ICB, UFMG, Belo
Horizonte - MG.
E-mail: fernanda.villani@cpqrr.fiocruz.br
Introduction: In the last 30 years we have seen a marked appearance of
emerging viral diseases, with approximately 100 new viruses identified, some
being related to major epidemics in humans. Among them the Apeu virus
(APEUV), a Orthobunyavirus of group C, has been described in human
infections. In addition to emerging viruses, the reemergence of pathogenic
viruses with high dissemination rate as the Poxvirus is a reality. Zoonotic human
infections caused by Vaccinia virus (VACV), a Orthopoxvirus, in Brazil reached
worldwide recognition. Most researchers that study antiviral immune response
mechanisms target the classical cell populations, such as CD4 + T lymphocytes
(T helper), CD8 + T lymphocytes (cytotoxic) and NK cells (natural killer).
Although these cells certainly have key functions in the immune response to
viral infections, other cell populations can also play an important role. Recently
it was shown that monkeys infected with immunodeficiency virus SIV, similar to
HIV, do not develop clinical disease (AIDS) and that the CD4 - CD8 - T cell
population (double-negative-DN) was responsible for compensating at least
partially, the function of CD4 + cell depleted in this disease. This suggests that
the DN T cells play an important role in the antiviral immune response. The aim
of this work was to evaluate the activation profile of DN T cells expressing
alpha-beta (αβ TCR) or gamma-delta T-cell receptors ( TCR) from healthy
humans.
Methods and Results: The peripheral blood mononuclear cells were isolated
from four donors and exposed to UV-inactivated APEUV and VACV (WR
isolate). The expression of surface markers (CD4, CD8, αβ TCR and TCR)
and the intracellular cytokines (IL-1β. IL-6, IL-10, IL-17A, IFN-α, IFN-β, IFN-
and TNF-α) were assessed by flow cytometry. We observed a higher frequency
of αβ DN T cells expressing IL-10, IFN-α and TNF-α in VACV stimulated cells
as compared to non-stimulated cells. IFN- expression was higher in VACVstimulated
DN T cells compared to non-stimulated cells. We did not observe
differences in the expression of these markers in cells stimulated with APEUV.
Conclusion: These results show that DN T cells from healthy humans are
highly activated in vitro by VACV and suggests an important role of these cells