Protective effect of purified outer membrane proteins of Salmonella enteric serovar Typhimurium against salmonellosis in mice

This study was designed to investigate the protective effect of non porin outer membrane proteins (OMPs) of Salmonella typhimurium against salmonellosis. Salmonella typhimurium isolated and microscopic
examination, some biochemical tests and API 20E identification had been carried out , the isolated previously from stool of infants suffering from diahrria then the outer membrane non porin proteins (OMPs) of this bacterium was extracted and analyzed by Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE). Results of protein profile of the S. typhimurium outer membrane revealed that bands with molecular weight ranged between (20-150) kDa were present. Purification by ion exchange chromatography on DEAE- cellulose and gel filtration chromatography on Sephacryl S- 200 was carried out to obtain purified non porin proteins with molecular weight 49 kDa. some immunological parameters (total and absolute count of leucocytes, phagocytic index, total gamma globuline percentage and histopathological changes of 49 kDa OMPs were evaluated. For this purpose twenty albino mice divided into four groups before subjection to various treatments. Results of immunological parameters were as follows: Group IV showed a significant increase in total count of leucocytes(6200 cells/cu.mm.blood), neutrophils (2554 cells/cu.mm.blood), monocytes(372 cells/cu.mm.blood ) and lymphocyte (3174 cells/cu.mm.blood) as well as a significant increase in phagocytic index (50.600% cells/cu.mm.blood) and total gamma globulin percentage (19.0%).
The Results of histopathological study exhibited that sections of spleen, intestine and liver of mice infected with Salmonella typhimurium showed mild degeneration and lost their structure appearance in the spleen, mild atrophy of villi in the intestine and degeneration of necrosis of hepatocytes cells in the liver. While sections of spleen, intestine and liver of mice treated with 49 kDa OMPs and infected with Salmonella typhimurium led to near normal appearance of spleen tissue, and intestinal villi but normal appearance in the liver.