Co-Expression of <i>hbha</i> and <i>mtb32C</i> Genes from <i>Mycobacterium tuberculosis</i> H37Rv in a Prokaryotic System

Abstract

Background: Heparin-binding hemagglutinin (HBHA) protein is a surface adhesin that mediates the attachment of Mycobacterium tuberculosis to host cells by its own unique, carboxyl-terminal region. The methylated HBHA has a specific motif with a lysine-, alanine-, and proline-rich domain. More recently, it has been shown that HBHA protein has potential activity in stimulating immune responses, and is a promising new candidate for diagnostic applications besides a protective antigen against tuberculosis. Objectives: The aim of this study was to isolate a mycobacterial latency gene (hbha), and subsequently produce its protein as a new antigen for the Interferon-Gamma Release Assay test (IGRAs). Methods: In the present work, hbha and mtb32C genes were isolated from the Mycobacterium tuberculosis H37Rv genome using the polymerase chain reaction (PCR) method. The PCR products and pet21+ vector were digested with specific restriction enzymes and then submitted to the ligation procedure. Escherichia coli BL21-CodonPlus (DE3) competent cells were transformed with the recombinant mtb32C-hbha -pet21+ vector. Expression of recombinant protein (Mtb32C-HBHA) was confirmed with Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) and western blot methods. Results: Detection of a 500-bp gene and sequencing of recombinant pet-mtb32C-hbha vector, all confirmed the accuracy of the cloning procedure. A 36-KDa band of Mtb32C-HBHA protein was also detected by western blotting. Conclusions: In this study, expression of Mtb32C-HBHA protein was successfully done, in the prokaryotic system. Further studies are needed to evaluate the efficacy of recombinant Mtb32C-HBHA protein in diagnosis of latent tuberculosis.