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

EVALUATION OF THE IMMUNE RESPONSE AGAINST BRUCELLA
ABORTUS IN SPLENECTOMIZED MICE
ALICE BELLEIGOLI REZENDE (1) ; NÁIRA NEVES NETO (1) ; CAROLINA DE
SOUZA MIRANDA (1) , MARCELA MOTA (1) ; POLLYANNA AMARAL
SALVADOR (1) ; GILSON COSTA MACEDO (1) ; HENRIQUE COUTO TEIXEIRA (1)
(1) Laboratório de Imunologia, Departamento de Parasitologia, Microbiologia e
Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Juiz de
Fora, Juiz de Fora – MG, Brasil
Introduction: The spleen plays an important role in immune function. However,
the influence of the spleen in control and progression of intracellular bacterial
infections remains unclear. Brucellosis is a zoonosis caused by the facultative
intracellular bacteria of the genus Brucella. According to World Health
Organization, thousands of new cases of human brucellosis are diagnosed
each year worldwide. In Brazil, bovine brucellosis is endemic throughout the
country, compromising the quality of cattle and causing a large annual loss for
the Brazilian economy. Brucella abortus has a tropism for the spleen and
induces an immune response mediated by cytokines such as IFN- and TNF-α.
The objective of this work was to investigate the immune response against
Brucella abortus in splenectomized mice.
Methods and Results: C57Bl/6 mice were divided into a sham-operated
control group (SH) and splenectomized group (SP). Thirty days after surgery,
animals were intraperitoneally infected with 10 6 bacteria/mouse of Brucella
abortus (S2308). Twenty one days after infection, B. abortus colony-forming
units (CFU) were evaluated in macerated liver. Cytokine production (IFN-, IL-
12, TNF-α, IL-6 and IL-10) was analyzed in liver by ELISA. A higher number of
B. abortus CFU was observed in liver of splenectomized mice (Ln = 3.8 ± 0.1) in
comparison to the sham-operated group (Ln = 3.4 ± 0.1). IFN- and IL-12
production was lower in liver of SP mice (600.3 ± 75.9 pg/ml and 1303 ± 99.3
pg/ml, respectively). In addition, SH animals presented a greater production of
TNF-α, IL-6 and IL-10 in liver in comparison to the splenectomized group
(p