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Updated: Jun 13, 2026
In Vivo Infection with Leishmania amazonensis to Evaluate Parasite Virulence in Mice
Published on: February 20, 2020
Immunopathological studies of Leishmania amazonensis infection in resistant and in susceptible mice
Flávia de Oliveira Cardoso1, Celeste da Silva Freitas de Souza, Verônica Gonçalves Mendes
1Laboratório de Imunomodulação e Protozoologia, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro, Brazil.
Abstract:
Leishmania amazonensis infection was studied in mice to evaluate the evolution of leishmaniasis. The association of different methods, such as lesion kinetics, limiting dilution analysis, and immunohistochemistry, established different levels of susceptibility and resistance. Mice were arranged in 3 groups: susceptible (C57BL/10 and CBA), relatively resistant (DBA/2), and resistant (C3H.He). The histopathological analysis of primary lesions and draining lymph nodes showed a predominance of eosinophils and mast cells in the initial phase of infection in all mice. However, the most susceptible mice presented a greater number of amastigotes and higher tissue damage. The immunoglobulin analysis showed that susceptible mice produced high levels of antibodies, whereas resistant and relatively resistant mice exhibited low production of antibodies. Resistant mice showed parasite persistency in the skin and lymph nodes, suggesting that the infection in these mice can be sustained through the infection of cells such as dendritic cells, fibroblasts, and other cells present in these organs.
Insights
This study reveals varying mouse susceptibility to Leishmania amazonensis infection. Resistant mice harbor persistent parasites, suggesting novel infection pathways in leishmaniasis.
Area of Science:
- Immunology
- Parasitology
- Infectious Diseases
Background:
- Leishmania amazonensis causes leishmaniasis, a neglected tropical disease.
- Understanding host-parasite interactions is crucial for developing effective treatments.
Purpose of the Study:
- To evaluate the evolution of Leishmania amazonensis infection in mice with different genetic susceptibilities.
- To characterize host immune responses and parasite persistence in susceptible and resistant mouse models.
Main Methods:
- Mice were categorized into susceptible (C57BL/10, CBA), relatively resistant (DBA/2), and resistant (C3H.He) groups.
- Lesion kinetics, limiting dilution analysis, and immunohistochemistry were employed to assess infection.
- Histopathological and immunoglobulin analyses were performed on primary lesions and lymph nodes.
Main Results:
- Susceptible mice exhibited higher parasite loads, significant tissue damage, and elevated antibody production.
- All mouse groups initially showed eosinophils and mast cells in lesions.
- Resistant mice displayed parasite persistence in skin and lymph nodes, indicating infection of dendritic cells and fibroblasts.
Conclusions:
- Host genetic background dictates susceptibility to Leishmania amazonensis.
- Resistant mice may sustain infection via persistent parasites in dendritic cells and fibroblasts.
- Further research into these cellular reservoirs is warranted for leishmaniasis treatment strategies.
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