Rapid immunodiagnostic assays for Mycobacterium Tuberculosis infection

Roba M Talaat,Gamal S Radwan,Kalied Bassiouny,Saleh A Saleh,Abdelaziz A Mosaad

doi:10.4236/health.2010.23025

Abstract

Purpose: There is a need for a continued effort to develop rapid immunodiagnostic assays for tuberculosis (TB) infection with greater sensitivity and specificity that can be used in the field and in the laboratory and that can be formatted for use with multiple species. This would help to obtain definitive early diagnosis of TB. The present study was developed to determine the role of using early secreted antigenic target-6 (ESAT-6) in immunodiagnosis of Mycobacterium tuberculosis. Methods: Serum samples were obtained from TB infected patients and normal healthy controls. Two rapid immunodiagnostic assays (Enzyme-linked immunosorbent assay (ELISA) and Immunoblotting) were performed. Results: The sensitivity of immunoblotting assay was 100%; however, ESAT-6 antigen was not able to discriminate between patients and normal controls. Application of direct ELISA using ESAT-6 antigen yielded 97.6% sensitivity and 75% specificity for the diagnosis of TB infection. Conclusion: In conclusion, the detection of antibodies against ESAT-6 antigen in the sera of TB patients by direct ELISA could be used as a preliminary assay for diagnosis of human M. tuberculosis infection. A combination of the ELISA with either radiological or microscopic examination is required to overcome the low specificity of the assay for negative results.

Highlights

Tuberculosis (TB) is a global health problem with onethird of the world’s population latently infected with Mycobacterium tuberculosis (MTB) and about 8 million cases of active disease occurring each year [1,2]
early secreted antigenic target-6 (ESAT-6) was subjected to SDS-PAGE followed by Comassie brilliant blue staining
On screening of the TB infected sera, the immunoblotting assay sensitivity was 100% as all TB infected patients reacted with ESAT-6

Summary

Introduction

Tuberculosis (TB) is a global health problem with onethird of the world’s population latently infected with Mycobacterium tuberculosis (MTB) and about 8 million cases of active disease occurring each year [1,2]. Due to the increasing numbers of persons with MTB in the last years, the worldwide dissemination of HIV infection, the strongest risk factor for MTB development, and the continual migration of people from areas with a high incidence of TB to highly industrialized countries, MTB is considered a global emergency [3,4,5,6]. Identification and treatment of persons with latent MTB infection who are at high risk of progressing to active disease, may contribute to TB control [7]

Objectives

Methods

Conclusion