Intracellular replication of parental B. abortus 2308, virB10 mutants, and virB10 complemented mutant strains in HeLa cells. (A) B. abortus 2308 (○), B. abortus virB10::Kan (▴), and B. abortus virB10::Gm (●). (B) B. abortus 2308 (○), B. abortus 2308 virB10::Kan(pVK8.3) (▴), B. abortus 2308 virB10::Gm(pBBR-virB10) (●), and B. abortus 2308 virB10::Kan(pBBR-virB10) (□). Each value is the mean ± standard deviation of two independent experiments performed in duplicate. ∗, P < 0.05; ∗∗, P < 0.01 (compared with strain 2308). Statistical analysis was performed with a t test.