BACKGROUND Dialyzable leukocyte extracts (DLEs) contain molecules smaller than 10 kDa with biological activity in receptor
organisms. Primarily, they participate in the regulation of the Th1 immune response, which is essential for the control of several
intracellular infections, such as toxoplasmosis. This disease is associated with congenital infection, encephalitis or systemic
infections in immunocompromised individuals. The clinical course of this infection fundamentally depends on a well-regulated
immune response and timely treatment with the appropriate drugs.
OBJECTIVE The aim of this study was to evaluate the effect of treatment with a leukocyte extract, derived from crocodile lymphoid tissue,
on the histopathology and brain parasite load in NIH mice that had been infected with cysts of
Toxoplasma gondii
(ME-49 strain).
METHODS The treatment was applied during the acute and chronic stages of the infection. Histopathological changes were
evaluated in the ileum, liver and spleen at one, four and eight weeks after infection and in the brain at week 8. The parasite load
was evaluated by counting the cysts of
T. gondii found in the brain.
FINDINGS Compared to the control mouse group, the mice infected with
T. gondii and under treatment with DLE showed less
tissue damage, mainly at the intestinal, splenic and hepatic levels. In addition, a greater percentage of survival was observed, and
there was a considerable reduction in the parasite load in the brain.
CONCLUSIONS The results suggest that DLE derived from crocodile is a potential adjunctive therapy in the conventional
treatment of toxoplasmosis.
