Submitted to: Infection and Immunity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/1996
Publication Date: N/A
Interpretive Summary: Cryptosporidium is an intestinal parasite of domestic animals which also infects humans with impaired immune systems. Molecular biological techniques were applied to cells of the immune system from infected and control calves to determine the type of cells responding to the infection. A study of the cell surface molecules and of the cytokine molecules secreted by these cells identified changes in the cell populations during infection. An understanding of the immune response of calves to this disease is expected to improve the quality of care given to domestic livestock and to better control this opportunistic infection with human patients with AIDS.
Technical Abstract: The objective of this study was to identify disease related changes in lymphocyte populations within ileal mucosa of calves with cryptosporidiosis. Groups of 5 neonatal calves were orally infected at days of age with 100 million oocyts and maintained in enteric pathogen free conditions until clinical disease was established, or until the animals had recovered from disease. Age matched uninfected calves were used for comparison. Ileal mucosal lymphocytes were collected, quantitated and phenotyped to determine whether changes in lymphocyte composition occurred in infected animals. We observed significantly larger numbers of intraepithelial CD8+ T lymphocytes in ileal mucosa from acutely infected calves compared with control animals. In addition, a proportion of intraepithelial CD4+ T cells from acutely infected calves coexpressed CD25, compared with the absence of coexpressed CD25 on CD4+ T cells from control calves. Ex vivo reverse transcriptase PCR of RNA from intaepithelial lymphocytes from control calves showed a cytokine expression pattern consisting of TNF-alpha and IFN-gamma, while intraepithelial lymphocytes from calves with cryptosporidiosis expressed IFN-gamma, but not TNF-alpha. Together, the results indicate changes occur in the ileal intraepithelial lymphocyte population coincident with C. parvum induced enteric disease.