Molecular and immunological characterization of Mycobacterium tuberculosis CFP-10, an immunodiagnostic antigen missing in Mycobacterium bovis BCG

• Published in: Journal of clinical microbiology Vol. 38; no. 9; pp. 3285 - 3290
• Main Authors: DILLON, D. C, ALDERSON, M. R, DAY, C. H, BEMENT, T, CAMPOS-NETO, A, SKEIKY, Y. A. W, VEDVICK, T, BADARO, R, REED, S. G, HOUGHTON, R
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01.09.2000
• Subjects: Adolescent; Adult; Amino Acid Sequence; Antibodies, Bacterial - blood; Antigens, Bacterial - chemistry; Antigens, Bacterial - genetics; Antigens, Bacterial - immunology; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - immunology; Bacterial Proteins - isolation & purification; Bacteriological methods and techniques used in bacteriology; Bacteriology; Biological and medical sciences; CFP-10 protein; culture filtrate protein 10; Enzyme-Linked Immunosorbent Assay; Female; Fundamental and applied biological sciences. Psychology; Humans; Immunoblotting; lhp gene; Lymphocyte Activation; Male; Microbiology; Molecular Sequence Data; Mycobacteriology and Aerobic Actinomycetes; Mycobacterium bovis; Mycobacterium bovis - genetics; Mycobacterium bovis - immunology; Mycobacterium tuberculosis; Mycobacterium tuberculosis - genetics; Mycobacterium tuberculosis - immunology; Recombinant Proteins - chemistry; Recombinant Proteins - immunology; Tuberculosis, Pulmonary - diagnosis; Tuberculosis, Pulmonary - microbiology; Human; Identification; Species specificity; Serology; Mycobacterial infection; Enzyme immunoassay; Infection; Antigen; Tuberculosis; Mycobacterium tuberculosis; Mycobacteriales; Bacteriosis; Mycobacteriaceae; Bacteria; Actinomycetes; Diagnosis; ELISA assay
• ISSN: 0095-1137; 1098-660X
• DOI: 10.1128/jcm.38.9.3285-3290.2000

In order to identify antigens that may be used in the serodiagnosis of active tuberculosis (TB), we screened a Mycobacterium tuberculosis genomic expression library with a pool of sera from patients diagnosed with active pulmonary TB. The sera used lacked reactivity with a recombinant form of the M. tuberculosis 38-kDa antigen (r38kDa), and the goal was to identify antigens that might complement r38kDa in a serodiagnostic assay. Utilizing this strategy, we identified a gene, previously designated lhp, which encodes a 100-amino-acid protein referred to as culture filtrate protein 10 (CFP-10). The lhp gene is located directly upstream of esat-6, within a region missing in M. bovis BCG. Immunoblot analysis demonstrated that CFP-10 is present in M. tuberculosis CFP, indicating that it is likely a secreted or shed antigen. Purified recombinant CFP-10 (rCFP-10) was shown to be capable of detecting specific antibody in a percentage of TB patients that lack reactivity with r38kDa, most notably in smear-negative cases, where sensitivity was increased from 21% for r38kDa alone to 40% with the inclusion of rCFP-10. In smear-positive patient sera, sensitivity was increased from 49% for r38kDa alone to 58% with the inclusion of rCFP-10. In addition, rCFP-10 was shown to be a potent T-cell antigen, eliciting proliferative responses and gamma interferon production from peripheral blood mononuclear cells in 70% of purified protein derivative-positive individuals without evident disease. The responses to this antigen argue for the inclusion of rCFP-10 in a polyvalent serodiagnostic test for detection of active TB infection. rCFP-10 could also contribute to the development of a recombinant T-cell diagnostic test capable of detecting exposure to M. tuberculosis.