RESUMO
Mice genetically selected for high (H) and low (L) antibody production (Selection IV-A) were used as murine experimental model. The aim of the present work was to evaluate the macrophagic activity and to characterize the immune response in Mycobacterium bovis-AN5 infected mice (3X10(7) bacteria). The response profile previously observed in such strains was not similar to that obtained during M. bovis infection; however, it corroborated works carried out using Selection I, which is very similar to Selection IV-A regarding infection by M. tuberculosis and Bacillus Calmette-Guérin (BCG). Considering bacterial recovery, L IV-A mice showed higher control of the infectious process in the lungs than in the spleen, whereas H IV-A mice presented more resistance in the spleen. With respect to macrophagic activity, hydrogen peroxide (H2O2) was probably not involved in the infection control since there was an inhibition in the production of this metabolite. Nitric oxide (NO) and TNF-alpha production seemed to be important in the control of bacterial replication and varied according to the strain, period and organ. Evaluation of the antibody production indicated that the multi-specific effect commonly observed in these strains was not the same in the response to M. bovis. Antibody concentrations were higher in L IV-A than in H IV-A mice at the beginning of the infection, being similar afterwards. Such data were compared with delayed-type hypersensitivity (DTH), which was more intense in H IV-A than in L IV-A mice, indicating that antibody production is independent of the capability to trigger DTH reactions and that cellular and humoral responses to M. bovis antigens show a polygenic control and an independent quantitative genetic regulation. Differences were observed among organs and metabolites, suggesting that different mechanisms play an important role in this infection in natural heterogeneous populations, indicating that NO, TNF-alpha and Th1 cytokines are involved in the infection control.
RESUMO
Visceral leishmaniasis is a zoonotic disease caused by parasites of the Leishmania genus. Dog is the major source of infection to man, especially in urban areas. The authors report a case of visceral leishmaniasis in a pit bull female dog from Bocaina, São Paulo, Brazil. The animal presented clinical signs compatible with leishmaniasis, including skin lesions in the body and partial damage of the external ears. The indirect fluorescent antibody test (IFAT) demonstrated a titer of 1280, and promastigote forms of Leishmania sp were isolated by the culture of bone marrow puncture. Cytological analysis of the lymph node and smear of the bone marrow puncture revealed macrophages containing amastigote forms of Leishmania sp in their inner region. The test of Polymerase Chain Reaction (PCR) utilized the primers LINR4 and LIN19, which amplify 720 base pairs, specific for Leishmania sp. The authors discuss the importance of techniques for a quick and precise diagnosis to this serious zoonosis with great impact in animal and public health.