Objective:To compare the efficiency and characteristics of different carrier proteins and signal sequences in delivering antigens into Escherichia coli outer membrane vesicles (OMVs). Methods:The fusion protein F1V, which consisted of the main protective antigen of Yersinia pestis F1 and LcrV, was expressed using the carrier proteins such as cytolysin A (ClyA), outer membrane protein A (OmpA), or β-lactamases (Bla) signal sequence as a carrier protein. The expression, localization, and content of F1V protein in OMVs were compared and analyzed. Results:All three delivery methods successfully incorporated F1V protein into OMVs and localized it on the surface of OMVs. Notably, when OmpA was used as the carrier protein, the F1V fusion protein constituted up to 30% of the total protein in OMVs. The highest yield of OMVs, reaching 4.2 mg/L, was achieved when Bla signal sequence was used as the carrier.Conclusions:There is a significant difference in the efficiency of different carrier proteins in delivering the F1V antigen into OMVs of Escherichia coli. Considering both the yield of OMVs and the proportion of antigen in the total protein of OMVs, the carrier Bla signal sequence demonstrated the highest efficiency in delivering F1V into OMVs, showing a potential for the future development of OMVs-based plague vaccines.

Objective:To compare the efficiency and characteristics of different carrier proteins and signal sequences in delivering antigens into Escherichia coli outer membrane vesicles (OMVs). Methods:The fusion protein F1V, which consisted of the main protective antigen of Yersinia pestis F1 and LcrV, was expressed using the carrier proteins such as cytolysin A (ClyA), outer membrane protein A (OmpA), or β-lactamases (Bla) signal sequence as a carrier protein. The expression, localization, and content of F1V protein in OMVs were compared and analyzed. Results:All three delivery methods successfully incorporated F1V protein into OMVs and localized it on the surface of OMVs. Notably, when OmpA was used as the carrier protein, the F1V fusion protein constituted up to 30% of the total protein in OMVs. The highest yield of OMVs, reaching 4.2 mg/L, was achieved when Bla signal sequence was used as the carrier.Conclusions:There is a significant difference in the efficiency of different carrier proteins in delivering the F1V antigen into OMVs of Escherichia coli. Considering both the yield of OMVs and the proportion of antigen in the total protein of OMVs, the carrier Bla signal sequence demonstrated the highest efficiency in delivering F1V into OMVs, showing a potential for the future development of OMVs-based plague vaccines.