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Enhanced mononuclear phagocytic activity during Trypanosoma cruzi infection in mice
Abstract:
It has been shown that Trypanosoma cruzi-infected mice develop a nonspecific resistance to challenge with an unrelated microorganism, namely, Listeria monocytogenes. This increased resistance to Listeria was observed on the 4th day of trypanosoma infection and persisted for at least 25 days. It was associated with an increased mononuclear phagocytic activity, as revealed by carbon clearance experiments. The possibility that macrophages of the infected host become activated by a process which appears to depend upon some form of specific interaction between the immune lymphoid cells and the infecting organisms, as has been demonstrated with other infectious agents, is discussed.
Insights
Trypanosoma cruzi infection in mice enhances resistance to Listeria monocytogenes. This nonspecific immunity, observed from day 4 to 25, correlates with increased macrophage activity.
Area of Science:
- Immunology
- Infectious Diseases
- Parasitology
Background:
- Trypanosoma cruzi infection can alter host immune responses.
- Nonspecific resistance to secondary infections is a known phenomenon in some parasitic diseases.
Purpose of the Study:
- To investigate the development of nonspecific resistance in Trypanosoma cruzi-infected mice against Listeria monocytogenes.
- To explore the underlying mechanisms of this enhanced resistance, focusing on phagocytic activity.
Main Methods:
- Induction of Trypanosoma cruzi infection in a mouse model.
- Challenge infection with Listeria monocytogenes at various time points post-T. cruzi infection.
- Assessment of host survival and bacterial load.
- Measurement of mononuclear phagocytic activity using carbon clearance assays.
Main Results:
- Trypanosoma cruzi-infected mice exhibited significantly increased resistance to Listeria monocytogenes challenge.
- This enhanced resistance was detectable by the 4th day of infection and persisted for at least 25 days.
- Carbon clearance experiments indicated heightened mononuclear phagocytic activity in infected mice.
Conclusions:
- Trypanosoma cruzi infection confers a period of enhanced, nonspecific resistance against unrelated bacterial infections like Listeria monocytogenes.
- The observed resistance is associated with activated mononuclear phagocytes, suggesting a role for macrophages in this phenomenon.
- Further investigation into the specific immune interactions driving macrophage activation is warranted.