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The course of Hymenolepis nana infections in thymus-deficient mice
Abstract:
The kinetics of infection with Hymenolepis nana was examined in normal thymus-deficient mice. Following inoculation with 5 cyticercoids, the number of adult lumen-dwelling H. nana in congenitally thymus-deficient (nude) mice ultimately was at least 75 times the maximum infection intensity of normal thymus-bearing mice or thymus-reconstituted nude mice. Similar results were obtained following inoculation of H. nana eggs into nude mice; although thymus-bearing mice eliminated their infections, nude mice harbored more than 1,000 adult worms throughout the 7 weeks of the experiments. These data show that in mice, immunity is not generated against H. nana in the absence of thymus function. The data also confirm and establish the requirement of cysticercoid development in the intestinal mucosa for stimulation of a protective immune response against H. nana.
Insights
Thymus function is crucial for developing immunity against Hymenolepis nana (tapeworm) infections in mice. Without a thymus, mice cannot mount an effective immune response, leading to severe tapeworm burdens.
Area of Science:
- Immunology
- Parasitology
- Infectious Diseases
Background:
- Hymenolepis nana is a common tapeworm with a complex life cycle.
- The role of the thymus in immunity against H. nana is not fully understood.
Purpose of the Study:
- To investigate the role of thymus-dependent immunity in H. nana infections.
- To determine if thymus deficiency affects the development of protective immunity against H. nana.
Main Methods:
- Infection kinetics of H. nana were studied in congenitally thymus-deficient (nude) mice and compared to normal thymus-bearing mice.
- Mice were inoculated with H. nana cysticercoids or eggs.
- Parasite burdens were quantified over a 7-week period.
Main Results:
- Thymus-deficient mice exhibited significantly higher H. nana burdens (at least 75 times greater) compared to normal or reconstituted mice.
- Thymus-bearing mice were able to eliminate H. nana infections, while nude mice maintained heavy infections.
- Cysticercoid development in the intestinal mucosa was confirmed as a requirement for stimulating an immune response.
Conclusions:
- Thymus function is essential for generating protective immunity against H. nana in mice.
- The development of H. nana cysticercoids in the intestinal mucosa is critical for eliciting an effective immune response.
- Immunity against H. nana is thymus-dependent.