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Published on: June 5, 2012
Concomitant immunity to Schistosoma mansoni in mice
Abdel-Moneim Salim1, Abdel-Rahman Al-Humiany
1Department of Medical Microbilogy, Taif University, Turaba, Saudi Arabia.
Objective:
The aim of the present study was to confirm observations on the concomitant immunity to Schistosoma mansoni in mice and assess its effects on the resistance of mice to a challenge infection.
Methods:
Cercariae from infected Biomphalaria glabrata were used to infect mice. Twenty mice were infected with a single dose of S. mansoni cercariae. The animals were randomly divided into two groups: experimental group (Group A) and control group (Group B). Group A mice were challenged with the same number of cercariae six weeks after the primary infection. Perfusion of all mice was done 9 weeks after infection in order to obtain worm burdens in relation to their initial cercarial dose. The livers of all mice were obtained for parasitological and pathological assessments.
Results:
Our results showed that all the exposed animals became infected with S. mansoni. After a challenge infection, Group A mice had a 54.66% worm reduction rate, 41.45% liver egg reduction rate, and 51.76% granuloma size reduction rate compared to their respective controls. This study shows that mice with persistent adult S. mansoni infection are able to mount a very strong regulatory response to a challenge infection. It is concluded that concomitant immunity does occur in mice.
Conclusion:
These results describe novel imaging methods that permit visualization of live schistosomes within their living hosts and may help to elucidate mechanisms of infection and also be of value not only for epidemiological investigations, but also in designing government control programs for schistosomiasis.
Insights
Mice infected with Schistosoma mansoni develop concomitant immunity, significantly reducing worm burden, liver eggs, and granuloma size upon re-exposure. This confirms a strong host regulatory response to persistent parasitic infection.
Area of Science:
- Immunology
- Parasitology
- Infectious Diseases
Background:
- Schistosomiasis is a major parasitic disease caused by Schistosoma mansoni.
- Concomitant immunity describes the host's ability to resist new infections while harboring existing ones.
Purpose of the Study:
- To confirm concomitant immunity in mice infected with Schistosoma mansoni.
- To evaluate the impact of this immunity on resistance to a secondary challenge infection.
Main Methods:
- Mice were infected with S. mansoni cercariae and divided into experimental (challenged) and control groups.
- Worm burdens, liver egg counts, and granuloma sizes were assessed 9 weeks post-infection.
- Parasitological and pathological evaluations were performed on mouse livers.
Main Results:
- Mice with persistent S. mansoni infection exhibited a significant reduction in worm burden (54.66%), liver eggs (41.45%), and granuloma size (51.76%) after challenge.
- This demonstrates a robust regulatory immune response in mice with ongoing S. mansoni infection.
- The findings confirm the occurrence of concomitant immunity in this model.
Conclusions:
- Concomitant immunity effectively limits new Schistosoma mansoni infections in mice.
- This phenomenon is crucial for understanding host-parasite dynamics in schistosomiasis.
- Further research may utilize these findings for schistosomiasis control strategies.
