Cloning and Expression of Com1 and OmpH Genes of Coxiella burnetii in Periplasmic Compartment of Escherichia coli with the Aim of Recombinant Subunit Vaccine Production

<em>Coxiella burnetii</em>is an obligate and gram-negative bacteria causing query fever (Q fever) disease, despite the importance of Q fever, there is no universal vaccine against this disease. Therefore, application of the recombinant subunit vaccines which use <em>Com1</em> and <em>OmpH</em> as immunogenic proteins can be useful in this regard. To perform the current project, <em>Com1</em> and <em>OmpH</em> genes were amplified by polymerase chain reaction (PCR) method, then, the PCR products were purified by DNA precipitation technique. In order to clone, first, both genes along with the pET-22b(+) vector were digested by <em>NcoI</em> and <em>XhoI</em> enzymes and then, <em>Com1</em> and <em>OmpH</em> genes were ligated in linear vectors by T4 DNA ligase. The recombinant vectors were transformed in BL21 (DE3) strain of <em>Escherichia coli</em> and expression was induced by 1 mM Isopropyl β-D-1-thiogalactopyranoside. Expression of <em>Com1</em> and <em>OmpH</em> was investigated using 12% Sodium dodecyl sulfate polyacrylamide gel electrophoresis. Finally, both proteins were purified by Ni-NTA columns and consequently confirmed by western blotting. The results of assessing 1% agarose gel showed that PCR amplification, DNA precipitation, and digestion of both genes were successfully performed.Theresults of colony PCRs and sequencing revealed that <em>Com1</em> and <em>OmpH</em> were correctly cloned in pET-22b(+) vector. Finally, the results of expression, purification, and western blotting of both proteins showed thatBL21 (DE3) strain of <em>Escherichia coli</em>could be able to express <em>Com1</em> and <em>OmpH</em> proteins<strong>.</strong> Based on the collected data, it seems that <em>Escherichia coli</em> as an affordable and simple host can be applied to express <em>Com1</em> and <em>OmpH</em> genes. It should be mentioned that products of the present project can be examined as recombinant subunit vaccines against Q fever.