It has been suggested that the development of humoral immune responses against Mycobacterium avium subsp. paratuberculosis (MAP), which causes Johne’s disease in ruminants, is correlated with the stage of infection and the age of the animal. In this study, antibody responses in cattle against MAP stress-associated recombinant proteins were assessed longitudinally by ELISA during the first 30 weeks after MAP infection. An increase in the levels of antibodies against five recombinant antigen preparations (MAP1027c, MAP1339, MAP1588c, MAP1589c, and MAP2411) was seen in MAP-infected calves (n = 16) but not in control calves (n = 3) over the period examined. Antibody responses were recorded as early as two weeks post-inoculation, and 87.5% of the infected cattle responded to at least one of the five immunogenic antigens within the first 30 weeks of infection. However, changes in the antibody levels in MAP-inoculated cattle showed great individual variability; three distinct types of antibody response profile, ‘persistent response’, ‘peak response’, and ‘no response’ were observed. The results suggest that these stress-associated proteins were expressed in vivo in MAP-infected cattle at a relatively early stage after infection and therefore stimulated the host’s immune system. We have also provided some evidence that humoral immunity occurs at an early stage of Johne’s disease and can be detected using appropriate antigens such as MAP stress-associated proteins.
(Bacterial and Parasitic Disease Research Division)
Kawaji S. et al. (2012) Vet. Immunol. Immunopathol. 150:101-111