ISOLATION OF SPECIFIC PEPTIDES FROM MYCOBACTERIUM-PARATUBERCULOSIS PROTOPLASM AND THEIR USE IN AN ENZYME-LINKED IMMUNOSORBENT-ASSAY FOR THE DETECTION OF PARA-TUBERCULOSIS (JOHNES DISEASE) IN CATTLE

  • 1 January 1983
    • journal article
    • research article
    • Vol. 44  (12) , 2229-2236
Abstract
An antigen was isolated from the protoplasm of M. paratuberculosis by a combination of gel filtration, ion exchange and affinity chromatography. The purified antigen constituted 7.8% of the total protein in the protoplasm. The specificity and sensitivity of the enzyme-linked immunosorbent assay (ELISA) for paratuberculosis, using the purified antigen, were evaluated with sera from 104 cattle which were examined (surveyed) for M. paratuberculosis infection by fecal cultural technique. The ELISA was positive in 50 of 60 infected animals. Of 44 noninfected animals, 5 were test-positive. When a crude protoplasmic extract was used as antigen in the ELISA, sera from 37 infected and from 18 noninfected animals were test-positive. Cross-reactions were encountered in complement-fixation test and the ELISA between crude or partially purified M. paratuberculosis antigens and antisera to Nocardia asteroides, M. avium, M. phlei and M. fortuitum. The purified antigen gave no complement-fixation reaction with any of these antisera. In the ELISA, cross-reaction was not found when purified antigen was used and the sera were screened at 1:40 dilution.