CONSTRUCTION OF AN ORAL VACCINE OF HELICOBACTER PYLORI UREASE SUBUNIT B WITH ATTENUATED SALMONELLA TYPHIMURIUM AS VECTOR / 解放军医学杂志

ABSTRACT

In order to construct a recombinant attenuated Salmonella typhimurium expressing Helicobacter pylori (H. pylori) urease subunit B(UreB), UreB gene fragment amplified by PCR was cloned into the prokaryotic expression vector pTC01 after sequencing, then transformed into attenuated Salmonella typhimurium SL3261 to acquire SL3261/pTC01-UreB. The expression of H. pylori UreB in SL3261 was detected by Western blot. Tewelve weeks after oral immunization of mice with this vaccine, anti-UreB IgA antibodies in mouse intestinal fluid and IgG antibodies in serum were determined by ELISA. IFN-? and IL-10 contents in the supernatant of spleen cell culture were also assessed by ELISA. The results showed that 61kD protein was expressed in SL3261/pTC01-UreB that could be recognized by anti-H. pylori UreB antiserum by Western-blot. The multiple oral immunizations with SL3261/pTC01-UreB could induce significantly H. pylori-specific mucosal IgA response as well as serum IgG responses. Moreover, there was significant increase of IFN-? and IL-10 contents in the supernatant of spleen cell culture in SL3261/pTC01-UreB group. These results suggested that the attenuated Salmonella typhimurium expressing H. pylori UreB may be used as oral vaccine against H. pylori infection. Its effect against H. pylori infection also needs to be further evaluated in animal models.