Cloning of ompA gene from Acinetobacter baumannii into the eukaryotic expression vector pBudCE4.1 as DNA vaccine

Antibiotic resistant features of Acinetobacter baumannii is partly due to the decreased outer membrane proteins (OMPs) permeability. The OmpA is one of the most conserved proteins among A. baumannii with a considerable antigenic potential to stimulate the multidimensional immune system responses. The present study was aimed to clone the ompA gene into the eukaryotic expression vector with potential as DNA vaccine. The ompA gene of A. baumannii was amplified using polymerase chain reaction (PCR). The target DNA was cloned and sub-cloned into the pTZ57R/T and pBudCE4.1 vectors, respectively. The recombinant vectors containing ompA were then validated using colony PCR, vector sequencing and double-digestion strategies. The pBudCE4.1-ompA recombinant plasmid was transfected into the human dermal fibroblast cells (HDF) and presence of ompA transcript and protein was evaluated using reverse transcribed-PCR (RT-PCR) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Our finding from colony PCR, sequencing and enzyme double digestion result confirmed that target gene has been successfully inserted into the pTZ57RT and pBudCE4.1. The presence of an expected band (1112 bp) in RT-PCR as wells as a 38 kDa band during SDS-PAGE showed that the recombinant pBudCE4.1-ompA construct was efficiently transfected into the HDF cells and expressed. Altogether, our observation demonstrated that the recombinant pBudCE4.1-ompA construct was successfully produced although further experiments are needed.