Identification of Rv2041c, a Novel Immunogenic Antigen from Mycobacterium tuberculosis with Serodiagnostic Potential

Abstract

Novel immunogenic antigens are continually required for the improvement of diagnostic techniques for Mycobacterium tuberculosis infection. Some proteins with serodiagnostic value are not expressed under normal culture conditions, but may be induced under specific conditions such as gradual oxygen depletion and low pH, and from inside macrophages. Using a customized amplification library, we previously found that Rv2041c from M. tuberculosis H37Rv was highly expressed in vitro under conditions of low pH and hypoxia. In this study, recombinant (r)Rv2041c was produced in Escherichia coli to examine its role in immune responses. Increased Rv2041c expression in vitro during dormancy and during infection in human macrophages was confirmed by Western blotting and reverse transcription polymerase chain reaction, respectively. Interestingly, positive antibody responses to rRv2041c were detected only in those patients with active tuberculosis (TB) and in mice infected with M. tuberculosis H37Rv. Finally, Rv2041c was used successfully in the serodiagnosis of active M. tuberculosis infection in Korean patients in conjunction with other M. tuberculosis proteins, including Ag85 complex, 38 kDa, rESAT‐6, rHSP‐X and rCFP‐10. Our Rv2041c–ELISA had comparable diagnostic sensitivity and equivalent specificity to the use of an M. tuberculosis H37Rv cellular extract. In addition, seven of 46 serum samples collected from TB patients (15.28%) showed positive antibody responses to Rv2041c, but not to the other proteins. These results suggest that Rv2041c can be used to increase assay sensitivity alongside well‐known antigens for the serodiagnosis of M. tuberculosis infection.

ATP-binding cassette (ABC) import systems of Mycobacterium tuberculosis : target for drug and vaccine development

“…Further, the treatment of this ABC importer component with lymphocytes from latent and active TB mice raised up the secretion of IFN-γ and TNF-α. In addition, it was reported that Rv2041c gives positive antibody response with Mtb infected mice as well as active TB patients [53]. It was also established that this protein provides the highest sensitivity similar to previously used serological antigens (CFP-10, ESAT-6, HSP-X, Ag85 complex, and PstS1) against active Mtb infection.…”

“…Further, treatment of Rv2041c protein with lymphocytes from latent and active TB mice raised up the secretion of IFN-γ and TNF-α. Moreover, they indicated positive antibody responses to Rv2041c only in active TB patients and Mtb infected mice [53]. Proof of concept for this approach has also been seen in other bacterial species, as the mutant of exsA (component of ABC transporter) in Brucella abortus reflected immunity in mice against virulent B. abortus challenged with mice immunized with commercial vaccine [88].…”

“…Rv2041c treatment with macrophages and lymphocytes shows elevated expression of pro-inflammatory cytokines and raised up secretion of IFN-γ and TNF-α, respectively [52] . Rv2041c gives positive antibody responses and high level of sensitivity with Mtb infected mice [53] Metal importers Iron importers (IrtA/Rv1348, IrtB/Rv1349, FecB2/Rv0265c, and FecB/Rv3044) SBP: FecB2(Rv0265c) TMD: Remains to be identify NBD: Remains to be identify…”

Biochemical Characterization of an In-House Coccidioides Antigen: Perspectives for the Immunodiagnosis of Coccidioidomycosis

“…Western blotting is often used to confirm whether experimental protein antigens can be used to diagnose patients suffering from other diseases [ 16 ]. The reaction with our antigen using this technique was positive for all sera from coccidioidomycosis patients, which demonstrates that the in-house antigen affords a high sensitivity of this immunological assay.…”

Coccidioidomycosis in armadillo hunters from the state of Ceará, Brazil

“…Therefore, tests for this mycosis should be performed on patients from endemic areas who report, even for a short period, symptoms of pneumonia (Kwok et al 2009). Clinical diagnosis of coccidioidomycosis can be difficult (Kim et al 2009), particularly in regions that are endemic for tuberculosis, such as CE, making laboratory analysis mandatory.…”