(333o) Rapid Screen Of Highly Efficient Vaccine Candidates By Immunoproteomics And Cross Immunoproteomics

Diseases caused by microorganisms can be controlled by vaccines, which require neutralizing antigens. Therefore, it is very important to identify highly efficient immunogens for immuneprevention.

By combining immunoproteomics and bacterial challenge after immunization, we developed a rapid method for screening protected antigens of pathogenic bacteria in aquaculture. Our approach may be divided into three consecutive steps. First, dominant immunogens of outer membrane proteins are screened by immunoproteomics. Second, proteins with the ability to induce production of neutralizing antibodies are identified from the immunogens by virulent bacterium challenge following vaccination. Third, vaccine candidates are determined by evaluation of neutralizing abilities. Information on the candidates has been obtained for further gene cloning by mass spectrometry. Our results indicate that highly efficient protected antigens were identified from the outer membrane proteome of Aeromonas hydrophila, in which an immunogen showed 71.4% protective ability with multivalent functions to A. hydrophila and Aeromonas sobria.

Moreover, a cross immunoproteomics was developed with the use of homogeneous and heterogeneous antibodies as the primary ones, which were prepared from bacterium as an antigen in Western blotting and other bacteria, respectively. These spots recognized by both homogeneous and heterogeneous antibodies were cross-protective antigens and identified with mass spectrometry. Their genes were cloned and expressed. The purified recombinant proteins were applied for investigation of cross-protective immunity in fish and mice. Two highly efficient vaccine candidates determined in V. parahaemolyticus outer membrane proteins could be against infections by not V. parahaemolyticus, but also V. alginolyticus, Aeromonas hydrophila and Pseudomonas aeruginosa, which indicates that two outer membrane proteins show universal function against bacteria.

In summary, the methodologies developed in the current study is high throughout and hence approached rapid, highly efficient and accuracy aims, which will play active role in immune prevention for microbiological diseases. This work was sponsored by grants from National Basic Research Program of China (2006CB101807) and ?863? project (2006AA09Z43Z).