Fig. 7. Effect of the mxiH mutation on secretion of effector proteins and invasion of HeLa cells. (A) Immunoblot analysis of secreted proteins from M94, spa47^–, mxiH^–, mxiH^– harboring pKT001 (mxiH^–/mxiH) or the S325 strain by addition of Congo red (0.003% final concentration) with antibodies specific for IpaB, IpaC and IpaD. S325 is a mxiA::Tn5 mutant used for negative control of Ipa secretion. WC, CS and PS denote the whole-cell lysate, Congo red-induced supernatant and supernatant in PBS, respectively. (B) Band pattern on a 10% SDS–polyacrylamide gel of secreted proteins from M94, spa47^–, mxiH^–, mxiH^– harboring pKT001 (mxiH^–/mxiH) or the S325 strain by addition of Congo red. The gel was silver stained. (C) Invasiveness of the mxiH mutant (mxiH^–) or the mxiH mutant harboring pKT001 (mxiH^–/mxiH) in HeLa cells by the gentamicin protection assay.