| The efficiency of any live bacterial vector vaccine hinges on its ability to present sufficient foreign antigen to the human immune system to initiate the desired protective immune response(s). However, synthesis of sufficient levels of heterologous antigen can result in an increase in metabolic burden with an accompanying decrease in the fitness of the live vector, which can ultimately lower desired immune responses to both live vector and heterologous antigen.The E. coli a -hemolysin(HlyA) secretion system is the prototypicl and best characterized type I secretion system. The structure and function of the components of the HlyA secretion apparatus, HlyB, HlyD and TolC have been studied in great detail. The application of a -hemolysin(HlyA) secretion system is a way of minimizing metabolic burden of some live bacterial vector vaccines, as well as enhancing the fitness and immunogenicity of some live bacterial vector. The functional characteristics of this secretion system enable it to be used in a variety of different applications.In this work, the ?coli J96 chromosomal hly determinant was obtained by PCR. A series of a-hemolysin secretion system recombinant plasmids have been constructed on the basis of pQE30 with foreign antigen genes and hly determinant. It was convinced that the secretion plasmid vector has been successfully obtained by DNA sequencing, SDS gel electrophoresis and Western blot. It has been found that the functions of these recombinant plasmids are not as efficient as those which have been reported. Several bacteria (including Salmonella enterica, Shigella, Vibrio cholerae, andListeria monocytogenes)vill be used as live bacterial vector of the a-hemolysin secretion system recombinant plasmid in the coming years, and the selection of the suitable promoter for the recombinant will be the emphasis of our research works as well as the optimal length of HlyAs.
|
PDF Full Text Request