| 摘要 |
<p>A recombinant attenuated microbial pathogen (I) comprises >= 1 heterologous nucleic acid molecule (NAM) encoding a Helicobacter (HB) antigen, where the pathogen is capable of expressing the NAM or capable of causing the expression of the NAM in the target cell. Also claimed is a method for identifying HB antigens which raise a protective immune response in a mammalian host by: (a) providing an expression gene bank of HB in an attenuated pathogen, and (b) screening the clones of the gene bank for their ability to confer protective immunity against a HB infection in a mammalian host. The pathogen is an enterobacterial cell, especially a Salmonella cell (preferably a Salmonella aro mutant cell) and the H. antigen is urease, an urease subunit, its immunologically reactive fragment or a peptide mimotope; or a secretory polypeptide from Helicobacter or its immunologically reactive fragment or a peptide mimotope, preferably selected from antigens AlpA and AlpB. The nucleic acid molecule encoding a Helicobacter antigen is capable to be expressed phase variably and is under control of an expression signal which is substantially inactive in the pathogen and which is capable to be activated by a nucleic acid reorganisation caused by a nucleic acid reorganisation mechanism in the pathogen.</p> |
