Mycobacterium avium subsp. paratuberculosis antigens induce cellular immune responses in cattle

Mycobacterium avium subspecies paratuberculosis (MAP) causes chronic progressive granulomatous enteritis leading to diarrhea, weight loss, and eventual death in ruminants. Commercially available vaccines provide only partial protection against MAP infection and can interfere with the use of current diagnostic tests for bovine tuberculosis in cattle. In the current study, we characterized immune responses in calves to vaccines containing either MAP fusion protein particles (MAP antigens Ag85A202-347-SOD1-72 -Ag85B173-330-74F1-148+669-786 as a fusion), recombinant MAP (rMAP) fusion protein or commercially available Silirum(R) vaccine. Thirty-two Holstein-Friesian cattle, 2-3 months old were sourced from a commercial farm with no history of JD. Prior to the trial, the cattle (n = 32) tested negative for reactivity to protein purified derivative from Mycobacterum avium (PPDA) (Prionics, Schlieren-Zurich, Switzerland) in the whole-blood interferon-g (IFN-g) assay were selected from a larger group of animals (n = 45). Thirty-two calves were divided randomly into 4 vaccine groups of 8 animals. The cattle were grazed on pasture in a separate paddock during the trial. RNA was prepared from the antigen-stimulated leukocytes before vaccination (week 0) and after vaccination (weeks 6, 9 and 12 of the study) and analyzed using PlexSet-24 consisting of probes specific to 21 immune response genes and 3 reference genes