Kinetics of mucosal ileal gamma-interferon response during cryptosporidiosis in immunocompetent neonatal mice.

The kinetics of serum and ileal interferon-gamma (IFN-gamma) content were determined during recovery from cryptosporidiosis in NMRI suckling mice. A total of 60 mice aged 4 days were inoculated by intragastric gavage with 10(4) cryptosporidia (n = 30) or phosphate-buffered saline (n = 30). Six animals per group were killed on days 0, 3, 6, 9 and 13 postinoculation. Blood samples and ileum were collected. Experimental infection was followed by a rise in parasite load in the ileum starting on day 3 postinfection, which peaked at day 6 postinoculation. Ileal IFN-gamma levels increased rapidly in parasitized mice from day 3 to day 6, then fell rapidly. These levels were significantly higher than the control values (day 3 P < 0.05, days 6 and 9 P < 0.001). IFN-gamma secretion began before parasite excretion, but the curves of these two parameters correlated positively. Recovery from cryptosporidiosis in immunocompetent neonatal mice is thus associated with an early and marked increase in ileal IFN-gamma content.