Application of an O-Linked Glycosylation System in Yersinia enterocolitica Serotype O:9 to Generate a New Candidate Vaccine against Brucella abortus

Abstract

Brucellosis is a major zoonotic public health threat worldwide, causing veterinary morbidity and major economic losses in endemic regions. However, no efficacious brucellosis vaccine is yet available, and live attenuated vaccines commonly used in animals can cause human infection. N- and O-linked glycosylation systems have been successfully developed and exploited for the production of successful bioconjugate vaccines. Here, we applied an O-linked glycosylation system to a low-pathogenicity bacterium, Yersinia enterocolitica serotype O:9 (Y. enterocolitica O:9), which has repeating units of O-antigen polysaccharide (OPS) identical to that of Brucella abortus (B. abortus), to develop a bioconjugate vaccine against Brucella. The glycoprotein we produced was recognized by both anti-B. abortus and anti-Y. enterocolitica O:9 monoclonal antibodies. Three doses of bioconjugate vaccine-elicited B. abortus OPS-specific serum IgG in mice, significantly reducing bacterial loads in the spleen following infection with the B. abortus hypovirulent smooth strain A19. This candidate vaccine mitigated B. abortus infection and prevented severe tissue damage, thereby protecting against lethal challenge with A19. Overall, the results indicated that the bioconjugate vaccine elicited a strong immune response and provided significant protection against brucellosis. The described vaccine preparation strategy is safe and avoids large-scale culture of the highly pathogenic B. abortus.

Production of a Promising Biosynthetic Self‐Assembled Nanoconjugate Vaccine against Klebsiella Pneumoniae Serotype O2 in a General Escherichia Coli Host

“…However, we found that the protection effect of the CTB‐based conjugate vaccines for O2 serotype of K. pneumoniae is not satisfactory as expected (Figure S4 , Supporting Information), [ 16 ] which might attribute to the weaker immunogenicity of its simple disaccharide repeat structure. In order to enhance immune response to this kind of polysaccharide antigens, a fully biosynthetic NP formed from proteinaceous monomers was used.…”

“…In previous studies, we successfully produced glycoconjugate vaccines in some attenuated pathogens. [ 16 ] The next step required a general host with low‐cost, ease of culture propagation, and scalability. The laboratory E. coli strain became a possibility.…”

“…After confirming the synthesis of heterologous K. pneumoniae serotype O2 polysaccharide in E. coli (Figure 1B ; and Figure S1 , Supporting Information), we hijacked this heterogeneous lipopolysaccharide (LPS) synthesis system to make bioconjugate vaccines bearing O2 polysaccharides by introducing the glycosyltransferase PglL, as we have demonstrated previously. [ 16 ] However, a relatively low efficiency of protein glycosylation was observed in E. coli W3110△ waaL strain (Figure S2 , Supporting Information). To improve the production of glycoproteins, we further knocked out of the remaining OPS synthesis related genes (five genes from wbbH to wbbL ), and named this modified host W3110△ waaL △ wbbH‐L (Figure S3 , Supporting Information).…”

Screening of potential vaccine candidates against pathogenic Brucella spp. using compositive reverse vaccinology

“…A limitation in this study is the selection of hypovirulent strain B. abortus S19 as challenge strain for protection experiments [ 43 , 71 , 72 ]. B. abortus S19 was originally isolated as a virulent strain from a Jersey cow in 1923 and was found to become attenuated after being kept in the laboratory at room temperature for more than a year [ 41 , 42 ].…”

Expression of Bordetella pertussis Antigens Fused to Different Vectors and Their Effectiveness as Vaccines

“…The most widely used one is cholera toxin B subunit (CTB) [ 11 ], which acts as a well-known mucosal adjuvant [ 12 , 13 ]. Moreover, both protein and bacterial polysaccharide antigens can be displayed on the CTB via fusion expression or glycosylation, which significantly improves the antigen-specific immune response evoked by the antigens [ 14 , 15 , 16 , 17 ]. Another AB5 family member is shiga toxin B subunit (StxB), which is also used as a carrier for immune enhancement.…”