Johne's disease affects ruminants causing an economic burden to dairy, meat and wool industries. Vaccination against Mycobacterium avium subspecies paratuberculosis (Map), which causes
Johne's disease, is a primary intervention for disease control in livestock. Previously, a comprehensive, multi-institutional
vaccine trial for
Johne's disease was conducted to test the efficacy of live attenuated Map strains. Here, we report the humoral and cell-mediated immune responses from kid goats enrolled in that trial. Both vaccinated and unvaccinated animals showed IFN-γ stimulation and proliferation of T cell subpopulations on challenge with Map. CD4+, CD25+ and γδ cells from cultured PBMCs in the vaccinated goats showed significantly greater proliferation responses on stimulation with Map
antigens. The increase in CD44+ and decrease in CD62L+ cells suggest that
vaccine administration reduced the inflammatory responses associated with Map
infection. Overall, a stronger antibody response was observed in the infected goats as compared to vaccinated goats. Two independent experimental approaches were used to identify differences in the antibody responses of vaccinated and unvaccinated goats. The first approach involved screening a phage expression library with pooled serum from infected goats, identifying previously reported Map
antigens, including MAP_1272c and MAP_1569. However, three specific
antigens detected only by vaccinated goats were also identified in the library screens. A second approach using dot blot analysis identified two additional differentially reacting
proteins in the vaccinated goats (MAP_4106 and MAP_4141). These immunological results, combined with the microbiological and pathological findings obtained previously, provide a more complete picture of
Johne's disease control in goats vaccinated against Map.