Implicações da esplenectomia e do transplante autógeno de baço na resposta imunológica contra Listeria monocytogenes e Escherichia coli em camundongos

Abstract

The splenectomy is a common proceeding in cases of abdominal traumas. In these cases the autogenous transplant of the spleen is the only alternative that preserves the functions of this organ. It has been reported that the incident of sepse for E. coli is larger in splenectomized animals. Meantime, in the infection by L. monocytogenes splenectomized individuals are better able to control the progression of the infection in comparison to individuals who have the spleen intact. In this work we evaluated the effect of splenectomy and of the autogenous transplant of the spleen on the capacity of BALB/c mice to control the infection by L. monocytogenes and E. coli. We evaluated the infection through the technique of bacteria CFU in the liver. The IFN- in liver and spleen was evaluated by ELISA, and the nitric oxide by the Griess method. Our results confirm that splenectomized animals (SP) present a lower number (P <0.05) of L. monocytogenes and larger number (P <0.05) of E. coli in the liver in comparison to the unsplenectomized control animals (CT). The animals that received the autogenous transplant of the spleen in the retroperitoneum (RP) or in the greater omentum (GO) showed a bacteria count in the liver similar to the CT group for both infections. SP animals infected by L. monocytogenes or E. coli presented a greater production of IFN- and NO in the liver in comparison to other groups studied. In the infection with L. monocytogenes SP mice had more accumulation of mononuclear cells in the liver, while in the infection with E. coli areas of tecidual necrosis were observed in the liver, although having a lower number of inflammatory cells, as well as low levels of IgM in the serum in comparison with the CT, RP, or GO groups. These results suggest that in the infection with E. coli the humoral immunity has an important function in the control of the infection. The production of IFNby splenic cells in both infections was similar in the transplanted groups in comparison to that in the CT group, suggesting that the fragments introduced behave in a way similar to the original organ. The realization of the autogenous transplant of spleen is able to reverse the effect of the splenectomy in the two infections studied, independent of the site used for the implantation.