Cytokine Gene Expression in Holstein-Friesian and Jersey Calves Infected with Mycobacterium avium subsp. paratuberculosis

Breed susceptibility to bovine Johne’s disease has been implied suggesting that Jersey cattle are more susceptible to disease as compared to Holstein-Friesian. A sixty-day experimental in vivo infection study was carried out by surgically infecting Holstein-Friesian and Jersey calves with the etiological agent of Johne’s disease, Mycobacterium avium subsp. paratuberculosis (Map). Breed-specific comparison of expression of key cytokine transcripts in the ileocecal lymph nodes of Map-infected and uninfected calves by real-time PCR did not indicate any significant differences. The expression of IFN-γ transcript was found to be significantly different for the treatment groups in both breeds with a higher expression level in infected than in control animals but there was no indication this differed between breeds. These data indicate that there are no breed-specific differences in the expression of key cytokine transcripts at sixty days post Map-infection and warrants long-term infection studies to analyze breed-specific immune response and in defining breed susceptibility.