FIG. 1.

Antibody responses to M. bovis culture filtrate (experiment 3). Mean antibody responses of animals vaccinated with high-dose CFP–IL-2 (▴), low-dose CFP–IL-2 (■), BCG (●), or adjuvant alone (⧫) and challenged with virulent M. bovis at 13 weeks after the initial vaccination (n = 11 for the high-dose CFP–IL-2 and adjuvant groups, n = 10 for the BCG group, and n = 4 for the low-dose CFP–IL-2 group) are shown. Data are expressed as absorbance indices and SE. ∗, means were significantly greater than the means of the BCG and adjuvant control groups (P < 0.05). V, vaccination; C, challenge.