Immunoproteomics Of Outer Membrane Proteins Of Salmonella Serotype Paratyphi A CMCC 50973

Typhoid is a acute systemic infection, including Typhoid caused primarily by Salmonella serotype Typhi and Paratyphoid caused by Salmonella serotypes Paratyphi A, B and C. Salmonella serotype Paratyphi A as a pathogen of Paratyphoid A are restricted to humans, especially children and young men, spreads by the fecal-oral route, and its infectious dose is 10~3 to 10~9 organisms. At present, there are estimated to be 22 million cases of Typhoid (including Paratyphoid) and more than 200,000 resulting deaths annually. In our country, the prevalent rate of Paratyphoid has an improving trend since 1996. Because the increasingly prevalent antibiotic-resistant forms and multiple-drug resistant forms of bacilli, Paratyphi A are more difficult and expensive to treat, many sufferer whose disease couldn't be eradicated become carrier. Therefore, a safety and effective vaccine for Paratyphi A need be developed and exploited.Immunoproteomic, as a branch of proteomics, could be successfully applied in the discovery of proteins with strong immunoreaction. By the 2-DE gels of pathogen proteins in combination with Western Blotting is respected method to found drug target and vaccine (because these proteins can cause immune response in host). Salmonella enterica is a group of Gram-negative enteric bacilli, which outer membrane proteins plays an important role both in bacterial pathogenesis and as a source of antigens. Because the membrane proteins (especially the outer membrane proteins) of bacteria can induce a good immune response in human beings, the role of proteins in conferring immunity to shigellosis is at best speculative. Considering outer membrane proteins of Salmonella enterica function as a dynamic interface between the cell and its surroundings, it is possible to develop new antigens from them. Thus, surface proteins of pathogen are very important in vaccine research. In this work , outer membrane proteins were extracted and performed two-dimensional electrophoresis of different pH gradient, reference map of OMPs were established and analyzed by software. 80 spots were cut out of the Coomassie-stained gel and in-gel digested. Sixty-one spots were identified successfully by MALDI-TOF-MS which represent 30 protein entries. The comparison between experimental and theoretical pI/MW distribution and their cellular role were analyzed. Furthermore, immunoproteomic techniques were used to research outer membrane proteins of Salmonella serotype Paratyphi A, the 2-DE gels of outer membrane proteins were electroblotted onto PVDF. By using the sera of convalescence, Western Blotting was performed with proteins of different components. Total 45 spots with immunoreactivity were detected in PVDF, 42 spots representing 23 antigens were identified. Analyzing their cellular localizations by PSORT (www.psort.org), 13 proteins were predicted in the outer membrane, 3 proteins were predicted in the cytoplasm, 1 protein was undefined, and 6 proteins had unknown cellular localization. These proteins are expected to become the candidates of drug target or vaccine.