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Schistosoma mansoni: unisexual infections sensitized mice for granuloma formation around intravenously injected eggs
A W Cheever1, F A Lewis, T A Wynn
1Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-0425, USA.
Abstract:
Mice carrying unisexual infection with male or female Schistosoma mansoni for 9 weeks developed accelerated and augmented reactions to S. mansoni eggs injected intravenously. The size of circumoval granulomas observed in the lungs of unisexually infected mice did not differ significantly from the reactions seen in bisexually infected mice. Tissue eosinophilia in the granulomas was also augmented similarly over that in naive mice by unisexual or bisexual infection. The cross-reactivity between worm and egg antigens is relevant to the development of acute toxemic schistosomiasis mansoni and, perhaps, to the consideration of antigens to be used for vaccination against S. mansoni infection.
Insights
Mice infected with only male or female Schistosoma mansoni showed stronger immune responses to S. mansoni eggs. This suggests cross-reactivity between worm and egg antigens is key in schistosomiasis mansoni.
Area of Science:
- Immunology
- Parasitology
- Pathology
Background:
- Schistosoma mansoni infection causes significant morbidity.
- The immune response to S. mansoni eggs is central to pathogenesis.
- Unisexual infections are less common but can provide insights into immune responses.
Purpose of the Study:
- To investigate the impact of unisexual Schistosoma mansoni infection on host immune responses to S. mansoni eggs.
- To compare granuloma formation and eosinophil infiltration in unisexually and bisexually infected mice.
Main Methods:
- Mice were infected with either male or female S. mansoni for 9 weeks.
- Intravenous injection of S. mansoni eggs was used to elicit egg-specific immune responses.
- Lung granuloma size and tissue eosinophilia were quantified.
Main Results:
- Unisexual S. mansoni infection accelerated and augmented host reactions to intravenously injected S. mansoni eggs.
- Granuloma size in the lungs of unisexually infected mice was comparable to bisexually infected mice.
- Tissue eosinophilia within granulomas was similarly augmented in both unisexually and bisexually infected mice compared to naive controls.
Conclusions:
- Cross-reactivity between S. mansoni worm and egg antigens influences host immune responses.
- These findings are relevant to understanding acute toxemic schistosomiasis mansoni.
- The study suggests potential considerations for developing S. mansoni vaccines based on antigen cross-reactivity.