Use of Recombinant ESAT-6:CFP-10 Fusion Protein for Differentiation of Infections of Cattle by Mycobacterium bovis and by M. avium subsp. avium and M. avium subsp. paratuberculosis

• Published in: Clinical and Diagnostic Laboratory Immunology Vol. 11; no. 4; pp. 729 - 735
• Main Authors: Waters, W.R, Nonnecke, B.J, Palmer, M.V, Robbe-Austermann, S, Bannantine, J.P, Stabel, J.R, Whipple, D.L, Payeur, J.B, Estes, D.M, Pitzer, J.E, Minion, F.C
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01.07.2004
• Subjects: Amino Acid Sequence; Animals; Antigens, Bacterial - genetics; Antigens, Bacterial - immunology; bacterial antigens; Bacterial Proteins - genetics; Bacterial Proteins - immunology; Base Sequence; biosynthesis; bovine tuberculosis; Cattle; cattle diseases; Cattle Diseases - diagnosis; Cattle Diseases - immunology; culture filtrate protein 10; Diagnosis, Differential; differential diagnosis; disease diagnosis; early secretory antigenic target 6; immune response; Interferon-gamma - immunology; interferons; leukocytes; Leukocytes - immunology; Microbial Immunology; Molecular Sequence Data; Mycobacterium avium - immunology; Mycobacterium avium avium; Mycobacterium avium paratuberculosis; Mycobacterium avium subsp. avium; Mycobacterium avium subsp. paratuberculosis; Mycobacterium bovis; Mycobacterium bovis - immunology; nitric oxide; paratuberculosis; purified protein derivative; recombinant antigens; recombinant fusion proteins; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - immunology; serodiagnosis; tuberculin; Tuberculosis, Bovine - diagnosis; Tuberculosis, Bovine - immunology; tumor necrosis factor-alpha; Tumor Necrosis Factor-alpha - immunology
• ISSN: 1098-6588; 1556-6811; 1071-412X; 1098-6588; 1556-679X
• DOI: 10.1128/CDLI.11.4.729-735.2004

Immunological diagnosis of Mycobacterium bovis infection of cattle is often confounded by cross-reactive responses resulting from exposure to other mycobacterial species, especially Mycobacterium avium. Early secretory antigenic target 6 (ESAT-6) and culture filtrate protein 10 (CFP-10) are dominant gamma interferon (IFN-γ)-inducing antigens of tuberculous mycobacteria, and they are absent from many environmental nontuberculous mycobacteria. Because M. avium exposure is the primary confounding factor in the diagnosis of M. bovis-infected animals, in vitro responses to a recombinant ESAT-6:CFP-10 (rESAT-6:CFP-10) fusion protein by blood leukocytes from cattle naturally exposed to M. avium or experimentally challenged with Mycobacterium avium subsp. avium or Mycobacterium avium subsp. paratuberculosis were compared to responses by M. bovis-infected cattle. Responses to heterogeneous mycobacterial antigens (i.e., purified protein derivatives [PPDs] and whole-cell sonicates [WCSs]) were also evaluated. Tumor necrosis factor alpha (TNF-α), IFN-γ, and nitric oxide responses by M. bovis-infected cattle to rESAT-6:CFP-10 exceeded (P < 0.05) the corresponding responses by cattle naturally sensitized to M. avium. Experimental infection with M. bovis, M. avium, or M. avium subsp. paratuberculosis induced significant (P < 0.05) IFN-γ and nitric oxide production to WCS and PPD antigens, regardless of the mycobacterial species used for the preparation of the antigen. Responses to homologous crude antigens generally exceeded responses to heterologous antigens. Nitric oxide and IFN-γ responses to rESAT-6:CFP-10 by blood leukocytes from M. bovis-infected calves exceeded (P < 0.05) the corresponding responses of noninfected, M. avium-infected, and M. avium subsp. paratuberculosis-infected calves. Despite the reported potential for secretion of immunogenic ESAT-6 and CFP-10 proteins by M. avium and M. avium subsp. paratuberculosis, it appears that use of the rESAT-6:CFP-10 fusion protein will be useful for the detection of tuberculous cattle in herds with pre-existing sensitization to M. avium and/or M. avium subsp. paratuberculosis.