A Candidate Oral Vaccine to Helicobacter pylori Fusion Protein of HspA and CtxB.
Heat-shock protein A subunit(HspA), an effective immunogen may stimulate the immunoresponse in human body against challenge of H.pylori. The B subunit of cholera toxin (CtxB) has been proved to be a potent mucosal immunogen, actas an adjuvant for vaccine targeted for delivery to the mucosal-associated lymphoid tissue. A recombinant plasmid expressing bivalent antigen of HspA and CtxB subunit was constructed as follows. hspA and ctxB gene was amplified by PCR. The DNA products of hspA and ctxB were inserted in the prokaryotic expression vector pET-22b( ), respectively, and then the resulted recombinant plasmid expressinga fusion protein named HCT was transformed into the E.coli strain BL-21(DE3). hct gene was measured to be 708 base pairs long, and the fusion protein encoding a polypeptide of 236 amino acid residues, corresponded to a calculated molecular masses of 30 kD. Western blot analysis of the recombinant protein HCT confirmed that it could be specifically recognized by the serum of H.pylori-infected patients. HspA and HCT labelled (125)I were orally administered into the stomach of mice, respectively, and the radioactivity of (125)I in serum of each mouse was assayed at intervals 15 min, 30 min, 60 min, 90 min and 120 min. The result indicated that there were high radioactivity counts in the groups of HCT than that of HspA(P 0.001). This result suggests that the CtxB may enhance the volume of HspA absorbed from the intestine of mice, therefore the recombinant fusion protein HCT may be an effective oral vaccine for prevention and treatment against the infection of H.pylori.
Li
Ming-Feng
MF
Shanghai Institute of Biochemistry, the Chinese Academy of Sciences, Shanghai 200031, China. xfwu@sunm.shcnc.ac.cn
He
Zhi-Yong
ZY
Ling
Zheng
Z
Wang
Jiao-Yang
JY
Sheng
Xu-Dong
XD
Yang
Guan-Zhen
GZ
Wu
Xiang-Fu
XF