MAP killing efficiency of macrophage fractions. Percentage of an initial MAP inoculum killed after infection for 5 days in macrophages isolated from HAV vaccinated (diamonds) or Sham vaccinated (squares) calves taken immediately prior to HAV boost (week -5) up to 36 weeks post challenge. Values given are averages of bovine IFN-? stimulated and unstimulated preparations performed in duplicate. Significance between groups is indicated as * P < 0.05, ** P < 0.01, *** P < 0.001.