Evidence for the emergence of a type-1-like immune response in intestinal mucosa of calves recovering from cryptosporidiosis.

This study was undertaken to characterize the mucosal response to Cryptosporidium parvum in infected calves that had recovered from diarrhea. Flow cytometric surface phenotypes of lamina propria lymphocyte (LPL) suspensions from infected calves and age-matched controls revealed the presence of a significantly larger proportion of CD25+ LPL in infected calves than in controls. Freshly isolated LPL from infected calves expressed more iNOS and interferon (IFN)-gamma than did controls. Infected calves excreted IgG1 and IgG2 isotype antibodies to C. parvum p23 by the end of the experiment. Moreover, immunohistochemistry of ileal sections revealed the presence of IgG1+ and IgG2+ B lymphocytes in the villi and IgG1+ but not IgG2+ B lymphocytes in continuous Peyer's patch nodules. These data are consistent with the emergence of a type-1-like mucosal immune response in terminal ileal mucosa as calves recover from cryptosporidiosis.