FIG. 2.

DNA-35 protects against virulent M. avium infection. Mice (n = 5) were immunized with DNA-35Cyt, DNA-35Sec or DNA-Neg, three times at biweekly intervals. Six weeks after the last injection, mice were infected i.v. with 10⁶ M. avium serovar 8. Other mice received BCG (5 × 10⁴ CFU of live BCG i.v.) or M. avium (MAC primed; 10⁵ CFU i.v.) followed by antibiotic treatment or were not immunized. Results represent the mean CFU ± SEM of five mice per group tested separately in the spleen (A) and liver (B). The differences between the following groups of mice were significant by Mann-Whitney test: DNA-35 and DNA-Neg in the spleen and liver at all time points tested (P < 0.01); DNA-35 and BCG in the spleen at week 4 (P < 0.05); MAC primed and DNA-Neg in the spleen and liver from week 4 onward (P < 0.01); and DNA-35 and MAC primed in the spleen (P < 0.01). These data are representative of two similar experiments.