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

IMMUNOPATHOLOGY OF MURINE CHROMOBLASTOMYCOSIS MODELS
RAFFAEL JÚNIO ARAÚJO DE CASTRO 1 ; KARINA SMIDT SIMON 1 ; ISAQUE
MEDEIROS SIQUEIRA 1 ; LUIZA CHAVES DE MIRANDA LEONHARDT 1 ; ANA
CAMILA OLIVEIRA SOUZA 1 ; ANAMÉLIA LORENZETTI BOCCA 1 .
1 Department of Cell Biology, University of Brasília - UnB.
Introduction: Chromoblastomycosis (CBM) is a chronic, suppurative,
granulomatous mycosis of the skin and subcutaneous tissues, whose main
etiologic agent is the dimorphic fungus Fonsecaea pedrosoi. However, the
literature lacks of a suitable animal model for the disease. With this in mind, the
current study was carried out aiming the immunopathology characterization of
experimental CBM, caused by the fungus F. pedrosoi in different murine strains.
Methods and Results: The ATCC 46428 strain of F. pedrosoi was cultivated
for 15 days under shaking and then filtered to obtain fungal propagules for
infection and its total soluble proteins (chromo-g). For a comparative study
between the current murine models of the disease, BALB/C, C57BL/6 and B10A
mice were infected subcutaneously with 10 6 fungal cells in its footpads.
Morphometric analysis of the footpads was performed in every 5 days post
infection. Every 15 days the animals were sacrificed and their footpad tissue
collected for CFU and histopathological analysis, as well as extraction of serum
for cytokine and nitric oxide quantification. Lymph node cells were collected
from draining popliteal lymph node for immunophenotyping and in vitro
lymphoproliferative response assays. All mice strains developed edema,
fibrosis, necrosis and suppurative granulomatous lesions in the footpad just like
those found in humans, showing also the presence of muriform cells, the
parasitic form of the fungus. The highest values of fungal burden were given 15
days post infection, showing gradual reduction up to 60 days post infection,
when the cure was reached. BALB/C mice showed an efficient recruitment and
proliferation of T lymphocytes after stimulation with F. pedrosoi and its secreted
proteins.
Conclusion: Taken together our previous data suggest that all strains, specially
BALB/C and C57BL/6 or in a less degree B10A, showed a similar
immunological and histopathological profile to that found in CBM patients,
although it appears to have a greater participation of cellular immunity, which
can explain the acute aspects of the disease in current murine models.
Support: CNPq and FAP-DF.