FIG. 2.

Residual virulence of B. melitensis Rev.1 strains (A) and B. abortus S19 strains (B). Spleen infection of CD-1 mice after subcutaneous injection of B. melitensis Rev.1 (■) and Rev.1ΔP39 (▵) and B. abortus S19 (•) and S19ΔP39 (◊). Shown are individual results (symbols), mean time courses (lines), and RT₅₀ (horizontal bars, with confidence limits, for mice receiving parent [black bars] and mutant [white bars] strains). Numbers in parentheses are numbers of negative mice out of eight receiving parent strains (bold numbers) and mutant strains (lightface numbers).