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Interferon-gamma and interleukin 4 gene expression in cows infected with Mycobacterium paratuberculosis
R W Sweeney1, D E Jones, P Habecker
1Department of Clinical Studies-New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square 19348, USA.
Objective:
To determine whether clinical progression of paratuberculosis in cattle was associated with alterations in cytokine gene expression in affected tissues.
Animals:
5 uninfected adult Holstein cows, 7 adult Holstein cows naturally infected with Mycobacterium paratuberculosis that did not have clinical signs of disease, and 4 adult Holstein cows naturally infected with M paratuberculosis that had progressive clinical signs of infection.
Procedure:
Samples of ileum and cecal lymph nodes were obtained from each animal at the time of slaughter. A reverse transcriptase-competitive polymerase chain reaction assay was used to determine mRNA expression of interferon-gamma (IFN-gamma) and interleukin 4 in each sample.
Results:
Interferon-gamma gene expression was significantly higher in ileum and cecal lymph node samples from subclinically infected cows than from clinically infected cows.
Conclusions And Clinical Relevance:
Progression of paratuberculosis to clinical stages is associated with reduced expression of IFN-gamma at site of infection. If immune response to M paratuberculosis can be manipulated so that IFN-gamma expression is increased, resistance to infection in cattle might be enhanced.