XI International Meeting on Paracoccidioidomycosis

XI International Meeting on Paracoccidioidomycosis

Resume:117-1

Poster (Painel)

117-1	Paracoccidioides brasiliensis-induced migration of respiratory dendritic cells and subsequent antigen presentation in the lung draining lymph node
Authors:	Suelen Silvana dos Santos (USP - Universidade de São Paulo) ; Karen Spadari Ferreira (UNIFESP - Universidade Federal de São Paulo - Campus Diadema) ; Sandro Rogério de Almeida (USP - Universidade de São Paulo)

Abstract

Paracoccidioidomycosis (PCM) is a systemic mycosis caused by Paracoccidioides brasiliensis (Pb), which mainly affects the lungs. They are one of the few organs that are in constant and intense interaction with the environment and the immune system. The great challenge for the pulmonary immune system is to discriminate what is harmful and react accordingly. Dendritic cells (DCs) are "professionals" antigen-presenting cells and they can do the antigen processing. They can also do the presentation of peptides to T lymphocytes and are ideal for maintaining this delicate balance between tolerance and an effector immune response. Knowing the importance of these cells in the immune system and that the infection by (Pb) preferentially attacks the lungs, cells from bronchoalveolar lavage (BAL), after experimental infection with yeasts of (Pb), were analyzed. We observed a significant increase of DCs in BAL after 24 hours of intratracheal infection with yeast cells of (Pb). The characterization of these cells showed that DCs expressed CD11c, MHC-II and DEC205. In order to verify the ability of migration of DCs, they were differentiated from bone marrow cells and pulsed with yeasts of (Pb), they were also labeled with CFSE and injected intratracheally into mice. As a negative control, we used PBS and DCs that were not pulsed with the fungus. The results showed that after 12 hours of infection, the DCs (CFSE+/CD11c+), migrated to the thoracic lymph nodes. However, the quantity of these cells decreases slightly after 24 hours of infection. Furthermore, we observed no DCs in regional lymph nodes when we analyzed the control groups. Thus, the lung cells were also labeled in vivo by injecting the CFSE dye intratracheally with yeasts of (Pb). We found that after 12 hours, pulmonary DCs of the animals infected with the fungus migrated to regional lymph nodes. These results indicate that the fungus Paracoccidioides brasiliensis was able to activate DCs, inducing their migration to regional lymph nodes, and inducing a response in that organ by T cells as evidenced by preferential production of IL-10.

Keyword: Paracoccidioidomycosis, Paracoccidioides brasiliensis, Dendritic cells

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