Tuberculosis (TB) remains to be a major
infectious disease throughout the world. However, the current
vaccine for TB has variable protective efficacy, and there is no commercially available serodiagnostic test for this disease with acceptable sensitivity and specificity for routine laboratory use. One of the potential strategies in developing a new diagnostic method and in improving the TB
vaccine involves the identification of novel antigenic candidates. This paper aims to identify systematically the novel antigenic
proteins with the greatest potential as protective or diagnostic
antigens by using the differential response of Mycobacterium tuberculosis
proteins to serum from TB patients and healthy individuals. Approximately 87% of the open reading frames of M.
tuberculosis were successfully cloned into
IPTG-inducible expression vectors. The clone sets were expressed in Escherichia coli, purified under denatured conditions, and tested for antigenicity using a mixture of sera from 15 TB patients. Out of the 3480
proteins screened, 249
proteins had significant reactions with the serum samples. Among the 249
proteins, 20
proteins were identified as most reactive. Compared with the commercial test kits, 3 novel
antigens from the top 20
proteins, namely, Rv1987, Rv3807c, and Rv3887c, provided better sensitivity and accuracy. These newly identified antigenic
proteins may be used as candidates for serodiagnostic application and
vaccine development. Overall, this study's findings may serve as an essential reference for developing new TB diagnostic methods and more effective
tuberculosis vaccines.