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Genetic resistance to Trypanosoma congolense infections in mice
Abstract:
The mechanisms of genetic resistance or "trypanotolerance" to infection with Trypanosoma congolense were investigated in two strains of mice. One strain C57BL, is outstandingly resistant to most stabilates of T. congolense and can survive for over 80 days, whereas CFLP, in common with most other strains, generally succumbs in less than 20 days. Evaluation of several pathophysiological and immunological parameters showed that after infection both strains initially developed similar levels of parasitemia, anemia, biochemical derangement, and immunosuppression. The most outstanding difference was after day 8 postinfection, when the susceptible strain (CFLP) sustained high levels of parasitemia (10(9) trypanosomes per ml) until death 2 to 4 days later, whereas the resistant strain (C57BL) showed a marked decrease to less than 10(6) trypanosomes per ml by day 10 postinfection. Clear evidence that this was associated with the presence of trypanocidal antibody in the resistant mice was provided by the results of an infectivity neutralization test on serum collected from each strain at 10 days postinfection. Chronically infected C57BL mice showed declining waves of parasitemia and a slow restoration of most hematological and biochemical indexes to near normal levels by 80 days postinfection, although at this stage they remained immunosuppressed.
Insights
Genetic resistance to Trypanosoma congolense infection, or trypanotolerance, was studied in mice. Resistant mice controlled parasite levels and produced antibodies, unlike susceptible mice.
Area of Science:
- Immunology
- Genetics
- Parasitology
Background:
- Trypanosomiasis is a significant disease in livestock and humans.
- Genetic factors influence host resistance to Trypanosoma congolense infection.
- Understanding trypanotolerance mechanisms is crucial for disease control.
Purpose of the Study:
- To investigate the mechanisms of genetic resistance (trypanotolerance) to Trypanosoma congolense in mice.
- To compare pathophysiological and immunological responses between resistant (C57BL) and susceptible (CFLP) mouse strains.
Main Methods:
- Infection of C57BL and CFLP mice with Trypanosoma congolense.
- Monitoring of parasitemia, anemia, and biochemical parameters.
- Immunological assessment using infectivity neutralization tests on serum.
Main Results:
- Both strains initially showed similar parasitemia, anemia, and immunosuppression.
- Resistant C57BL mice exhibited a significant decrease in parasitemia by day 10 postinfection.
- Susceptible CFLP mice maintained high parasitemia, leading to death within 20 days.
- Trypanocidal antibodies were detected in resistant C57BL mice serum.
- Chronically infected C57BL mice showed partial recovery but remained immunosuppressed.
Conclusions:
- Genetic resistance to Trypanosoma congolense in C57BL mice is associated with the development of trypanocidal antibodies.
- Trypanotolerance involves controlling parasite levels and mounting an effective immune response.
- Further research into these mechanisms could inform strategies for combating trypanosomiasis.