BCG ΔPtpA or BCG (ΔPtpA + PtpA Δ1-20) infection significantly decreased the size and weight of the xenograft tumor as compared with that of WT BCG, BCG (ΔPtpA + PtpA) and BCG (ΔPtpA + D126A) groups at 9 and 12 days after injection (Fig. 10a–c). This evidence concerns the gene PTPA and infection.