Persistent Cryptosporidium infection in congenitally athymic (nude) mice

Area of Science:

• Immunology
• Parasitology
• Gastroenterology

Background:

• Cryptosporidium infections can cause significant gastrointestinal distress.
• The role of the host immune system, particularly T cells, in controlling Cryptosporidium is not fully understood.
• Nude mice (nu/nu) are immunodeficient due to a lack of T lymphocytes, serving as a model to study T cell-dependent immunity.

Purpose of the Study:

• To investigate the role of T cells in the host immune response to experimental Cryptosporidium infection.
• To characterize the intestinal pathology associated with persistent versus transient Cryptosporidium infections in immunodeficient and immunocompetent mice.

Main Methods:

• Experimental infection of nude (nu/nu) BALB/c mice and their immunocompetent littermates (nu/+) with Cryptosporidium sp. at 6 days of age.
• Clinical observation for diarrhea and mortality.
• Histopathological examination of small and large intestines at 11 and 56 days post-infection.

Main Results:

• Nude mice developed persistent Cryptosporidium infections with diarrhea and occasional death, while white mice showed transient infections.
• Both nude and white mice exhibited villus atrophy and crypt hyperplasia in the small intestine at 11 days.
• Persistently infected nude mice displayed additional large intestinal lesions, including mucosal hyperplasia and crypt abscesses, by 56 days.

Conclusions:

• T cells are essential for the resolution of Cryptosporidium infections in mice.
• T cells are not required for the development of intestinal epithelial damage (villus atrophy, crypt hyperplasia) in cryptosporidiosis.
• Both nude and immunocompetent mice showed increased resistance to infection with age.