title: Isolation of specific peptides from Mycobacterium paratuberculosis protoplasm and their use in an enzyme-linked immunosorbent assay for the detection of paratuberculosis (Johne's disease) in cattle.
abstract: An antigen was isolated from the protoplasm of Mycobacterium 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. Five of 44 noninfected animals were also 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 both 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.
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology / Q000302:isolation & purification*; D001426:Bacterial Proteins / Q000302:isolation & purification*; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis*; D003168:Complement Fixation Tests / Q000662:veterinary; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D009161:Mycobacterium / Q000276:immunology*; D010283:Paratuberculosis / Q000175:diagnosis*; D010455:Peptides / Q000302:isolation & purification*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D010455:Peptides