Mao Xuhu

Fusion expression and immunogenicity of Bordetella pertussis PTS1-FHA protein: implications for the vaccine development

Mutants of pertussis toxin (PT) S1 subunit and filamentous hemagglutinin (FHA) type I immunodominant domain from Bordetella pertussis (B. pertussis) are considered to be effective candidate antigens for acellular pertussis vaccines; however, the substantial progress is hampered in part for the lack of a suitable in vitro expression system. In this paper, the gene sequences of a S1 mutant C180-R9K/E129G (mS1) and a truncated peptide named Fs from FHA type I immunodominant domain were linked together and constructed to pET22b expression vector as a fusion gene; after inducing with IPTG, it was highly expressed in E. coli BL21 (DE3) as inclusion body. The fusion protein FsmS1 was purified from cell lysates and refolded successfully. The result of Western blotting indicate that it was able to react with both anti-S1 and anti-FHA McAbs; antiserum produced from New Zealand white rabbits immunized with this protein was able to recognize both native PT and FHA antigens as determined by western blotting. These data have provided a novel feasible method to produce PT S1 subunit and FHA type I immunodominant domain in large scale in vitro, which is implicated for the development of multivalent subunit vaccines candidate against B. pertussis infection.

An efficient method to produce recombinant bacterial effector Tir coupled cytoskeleton protein (TCCP) complexed with host protein insulin receptor tyrosine kinase substrate (IRTKS)

An important pathogenic process in enterohemorrhagic Escherichia coli (EHEC) associated diseases is the formation of attaching and effacing (A/E) lesions, which are a typical pathological change in host cells. The classical pathway for A/E lesion formation requires the participation of proteins from both bacteria and host cells, namely intimin, translocated intimin receptor (Tir), insulin receptor tyrosine kinase substrate (IRTKS), Tir coupled cytoskeleton protein (TCCP), ARP3/2, and N-WASP. The interaction between IRTKS and TCCP is mediated by the binding of the SH3 domain of IRTKS (SH3IRTKS) to the proline rich repeat (PRR) domain of TCCP, which is important for the induction of A/E lesions. The inability to efficiently produce the purified target complex has hindered the structural determination of these protein complexes. Here, we report an effective method for the generation of a complex consisting of SH3IRTKS with three PRRTCCP domains. Two recombinant fragments, TCCP3R and TCCP5R, as well as SH3IRTKS, were successfully expressed in soluble form and purified. In addition, methods were established to prepare two different protein complexes, SH3IRTKS-TCCP3R and SH3IRTKS-TCCP5R. These methods are a good foundation for future studies on the crystal structure of TCCP-IRTKS. Meanwhile, recombinant TCCP was shown to directly bind to IRTKS in vitro, which provides additional evidence for the interaction between these two molecules.