Identification of the argT mutants and the results of invasion assays. (A) Identification of the argT deletion mutant. (B) Identification of the ArgT over-expression strain. The confirmed argT mutant strains and the wild-type strain were used for competitive invasion assays in HeLa cells (C) and BALB/c mice (D), respectively. The results show that the competitive index of the argT deletion mutant in the cell invasion assay was the same as the control, while the competitive index of the ArgT over-expression strain in the two kinds of invasion assays were both significantly lower (*, P < 0.05) than the control.