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

PARACOCCIDIOIDES BRASILIENSIS INHIBITS HUMAN DENDRITIC CELLS
MATURATION AND EICOSANOIDS PRODUCTION
REGINALDO KELLER FERNANDES (PG) (1), LUCIANE ALARCÃO DIAS-
MELICIO (2), MARJORIE DE ASSIS GOLIM (3), TATIANA FERNANDA
BACHIEGA (1), DANIELA RAMOS RODRIGUES (1), HELANDERSON DE
ALMEIDA BALDERRAMAS (1), ÂNGELA MARIA VICTORIANO DE CAMPOS
SOARES (1).
(1) Departamento de Microbiologia e Imunologia, Instituto de Biociências de
Botucatu, UNESP – Univ Estadual Paulista, Brasil; (2) Departamento de
Patologia, Faculdade de Medicina de Botucatu, UNESP – Univ Estadual
Paulista, Brasil; (3) Hemocentro, Faculdade de Medicina de Botucatu, UNESP
– Univ Estadual Paulista, Brasil.
Introduction: The dimorphic fungus Paracoccidioides brasiliensis (Pb) is the
etiologic agent of paracoccidioidomycosis, a systemic mycosis that is endemic
in Latin America. Dendritic cells (DCs) are believed to be critical in the detection
of pathogens and the initiation of the host response to microbial invasion. Many
mediators secreted by these cells, by an autocrine manner, can modulate their
functions. Among these mediators, the eicosanoids such as prostaglandins and
leukotrienes have become the focus of investigation in last years. Interactions of
human DCs with P. brasiliensis and their consequences in relation to the
functions of these cells, such as maturation, migration and cytokine production
are poorly understood. In this context, we sought to evaluate the maturation of
human of DCs and the production of PGE2 and LTB4 in response to high and
low virulent strains of the fungus. Methods and Results: Human DCs were
obtained from differentiation of monocytes cultured in the presence of GM-CSF
(80ng/mL) and IL-4 (80ng/mL) for 7 days. Flow cytometry assays identified
these cells as CD14 - /CD1a high /CD83 low , confirming the phenotype of immature
dendritic cells (iDCs). After, iDCs were incubated with LPS or challenged with
high and low virulent strain of the fungus, Pb 18 and Pb 265, respectively,
during 1h, 2h, 4h, 8h, 12h, 18h, 24h or 48h, followed by measurement of PGE2
and LTB4 levels using competitive ELISA Kits. The results showed that control
cells produced substantial concentrations of PGE2 and LTB4. Incubation with
LPS resulted in PGE2 increase (mainly at 18, 24 e 48h) but not in LTB4.
Differently, the inhibition of PGE2 and LTB4 release was detected after