Exposed immunogenic loops of BauA and Omp۳۴ displayed on the loopless C-lobe of the TbpB surface lipoprotein of Neisseria meningitidis trigger antibodies against Acinetobacter baumannii in a murine model

Background and Aim : The complexity of treating Acinetobacter baumannii infections due to the emergence of resistant strains has led researchers to design different types of vaccines. Omp۳۴ is one of several pathogens of Acinetobacter baumannii that its important role in the pathogenesis and survival of this bacterium has been proven. According to studies and understanding the important role of protein BauA (Baumannii Acinetobactin Utilization), which is produced under iron deficiency conditions and is required for the transfer of acinetobactin (iron-containing siderophore) to bacterial cells, makes it necessary to use BauA and Omp۳۴ to make vaccines.Methods : A new hybrid antigen approach was used in which the superficial epitopes of the TbpA receptor protein of Neisseria meningitidis were displayed on the C-lobe derivative of the TbpB surface lipoprotein, named the loopless C-lobe (LCL). The nucleotide sequences of the immunogenic loops were amplified and cloned into the LCL. After designing specific primers from the desired genes and regions and gene amplification, for replication, the amplified fragment was treated with a vector in the desired enzymatic digestion reaction. Then, using ligase enzyme, the digested fragment was SOE-PCR into the LCL at the designated position, and the resulting fragment was inserted into the expression vector. The recombinant proteins were expressed and purified using a Ni-NTA column. After the immunization of the laboratory animal, the production of antibodies against the recombinant proteins was assessed by indirect ELISA. The hybrid antigens were used to immunized mice followed by challenge experiments with a clinical isolate of A.baumannii (ABI۰۲۲). Results : Mice immunized with the hybrid antigen of the BauA loop۷ (BauAL۷P۳) and Omp۳۴ loop ۳ (Omp۳۴L۳P۱) brought protection against A. baumannii infection. Conclusion : The findings support the use of multiantigens to induce broadly reactive antibody responses against heterologous A. baumannii strains.

کلیدواژه ها:

Immunogenicity. ، Vaccine. ، BauA. ، Omp۳۴. ، Acinetobacter baumanni. ، Hybrid antigen