Lobomycosis is a chronic, granulomatous, fungal infection of the skin and
subcutaneous caused by the fungus Lacazia loboi. This mycosis occurs predominantly in
Amazon region and affect all populations groups. Histologically, there is a chronic
inflammatory reaction characterized by the intense fibroplastia and histiocytosis, abundant
number of macrophages, multinucleated giant cells and presence of large numbers of yeast.
Macrophages are phagocytic cells that participate in the recognition and response to
pathogens through phagocytosis, antigen presentation to T lymphocytes and cytokine
production. Langerhans cells (LC) are a group of dendritic cells (DC) derived from bone
marrow, which are located mainly in the suprabasal layer of the epidermis. Studies on hostfungal
interaction in Jorge Lobo's disease are scarce. Therefore, this study constitutes an
important step towards a better understanding of L. loboi biology and pathogenesis, enabling
in vitro culture of this organism endemic in Amazon region and study of their antigenic
properties, as well as new therapeutic approaches. The objective of this study was to analyze
the in vitro interaction between non-activated peritoneal macrophages and/or Langerhans cells
isolated from BALB/c mice and L. loboi, calculating infection, phagocytosis and cellular
fusion rates; also measuring the production of TNF, IL-4, IL-6, IL-10 and IL-12. Results
showed that L. loboi is phagocytosed by macrophages but not by LC. Phagocytosis and
infection rates in the interaction between macrophages and L. loboi was similar to interaction
between macrophages, Langerhans cells and L. loboi at all times analyzed. The mean number
of yeast cell per macrophage was almost equal among interactions and over time, with mean
variation from 1.2 to 1.6 yeast/macrophages. No giant cells formation in coculture studied. No
significant difference occurred in IL-4, Il-2 and IL-10 production between interactions
studied. TNF levels decrease in interaction between macrophages and L. loboi while adding
LC induces increased production of TNF-α, especially after 48 hours. LC negatively modulate
IL-6 production by macrophage and L. loboi also inhibits this production by macrophages
alone or cocultured with LC. L. loboi stimulated significantly IL-12 production by
macrophages co-cultured with LC, but not for LC alone or macrophages.
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