Design and immunological properties of Helicobacter pylori glycoconjugates based on a truncated lipopolysaccharide lacking Lewis antigen and comprising an ¦Á-1,6-glucan chain

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• 作者：Eleonora Altman^a ; ^{Eleonora.altman@nrc-cnrc.gc.ca} ; Vandana Chandan^a ; Blair A. Harrison^a ; Roberto Veloso-Pita^b ; ¹ ; Jianjun Li^a ; Rhonda KuoLee^a ; Wangxue Chen^a ; Vicente Vé ; rez-Bencomo^b ; Regional Helicobacter pylori Study Group ^c ; ²
• 关键词：Helicobacter pylori ; Conjugate vaccine ; LPS ; Bactericidal assay
• 刊名：Vaccine
• 出版年：2012
• 出版时间：26 November, 2012
• 年：2012
• 卷：30
• 期：50
• 页码：7332-7341
• 全文大小：1009 K

文摘

To investigate the vaccine potential of H. pylori lipopolysaccharide (LPS), truncated LPS of H. pylori strain 26695 HP0826::Kan lacking O-chain polysaccharide and comprising an extended ¦Á-1,6-linked glucan chain was conjugated to tetanus toxoid (TT) or bovine serum albumin (BSA). Two approaches were used for delipidation or partial delipidation of H. pylori LPS: (1) mild hydrolysis resulting in delipidated LPS (dLPS) and (2) treatment with anhydrous hydrazine resulting in removal of O-linked fatty acids (LPS-OH). Both LPS-OH and dLPS were covalently linked through a 2-keto-3-deoxy-octulosonic acid (Kdo) residue to a diamino group-containing spacer, followed by conjugation to thiolated TT or BSA to give conjugates LPS-OH-TT, dLPS-BSA and dLPS-TT, respectively. The LPS-OH-TT, dLPS-BSA and dLPS-TT conjugates were immunogenic in both rabbits and mice, inducing strong and specific IgG responses against homologous and heterologous strains of H. pylori. Moreover, the rabbit post-immune sera showed cross-reactivity against clinical isolates of H. pylori in a whole-cell indirect ELISA, which was further confirmed by indirect immunofluorescent microscopy. A tenfold stronger IgG immune response to the immunizing antigen was generated in mice and rabbits that received dLPS-containing conjugate. The post-immune sera of rabbits immunized with LPS-OH-TT, dLPS-BSA or dLPS-TT displayed significant bactericidal activity against mutant and wild-type ¦Á-1,6-glucan-expressing strains and selected clinical isolates of H. pylori. Finally, partial protection against H. pylori challenge was demonstrated in mice vaccinated with dLPS-TT conjugate adjuvanted with cholera toxin. In summary, this study shows that glycoconjugates based on delipidated or partially delipidated LPS from H. pylori 26695 HP0826::Kan mutant induce broadly cross-reactive functional antibodies in immunized animals and should be considered for further vaccine development and testing.