Assay for antibodies to mycobacterium paratuberculosis

Abstract

A method of detecting an immune response to a paratuberculosis-specific antigen, comprising incubating a sample from a subject with the paratuberculosis-specific antigen and detecting the presence of an antibody in the sample as an indication of an immune response to the paratuberculosis-specific antigen. The antigen may be obtained from a novel M. paratuberculosis strain JTC303. The antigen may be obtained from the JTC303 culture filtrate. Also provided are antibodies to the paratuberculosis-specific antigen, and a diagnostic kit for the detection of an immune response to a paratuberculosis-specific antigen in a mammal.

1 . An isolated  M. paratuberculosis  strain JTC303, deposited as PTA-7788 with the American Type Culture Collection on Aug. 15, 2006. 
     
     
         2 . A mutant of the  M. paratuberculosis  strain JTC303 of  claim 1 , which is capable of producing a paratuberculosis-specific antigen. 
     
     
         3 . An antigen isolated from the  M. paratuberculosis  strain JTC303 of  claim 1  or the mutant of  claim 2 . 
     
     
         4 . The antigen of  claim 3 , in culture filtrate. 
     
     
         5 . An isolated antibody that binds to the antigen of  claim 3  or  4 . 
     
     
         6 . The antibody of  claim 5  wherein the antibody binds to an antigen from the  M. paratuberculosis  strain JTC303 culture filtrate. 
     
     
         7 . The antibody of  claim 5 , which is a monoclonal antibody. 
     
     
         8 . The antibody of  claim 5 , which is a polyclonal antibody. 
     
     
         9 . The antibody of  claim 5 , which is labeled. 
     
     
         10 . A method of detecting an immune response to a paratuberculosis-specific antigen in a subject, comprising the steps of:
 (a) contacting a sample from the subject with a culture filtrate obtained from  M. paratuberculosis  strain JTC303, and   (b) detecting the presence of an antigen-bound antibody in the sample to indicate an immune response to the paratuberculosis-specific antigen.   
     
     
         11 . The method of  claim 10  further comprising absorbing nonspecific antibodies in the sample using a  Mycobacterium  cellular extract, wherein absorbing is performed prior to contacting the sample with the culture filtrate. 
     
     
         12 . The method of  claim 11  wherein the cellular extract is from  M. phlei  or  M. terrae.    
     
     
         13 . The method of  claim 11  wherein step b) comprises using an enzyme-linked immunosorbent assay (ELISA). 
     
     
         14 . The method of  claim 13  wherein the ELISA has a sensitivity of at least 50%, while having a specificity of at least 97%. 
     
     
         15 . The method of  claim 13  wherein the subject is human. 
     
     
         16 . The method of  claim 13  wherein the subject is bovine. 
     
     
         17 . The method of  claim 13  wherein the sample is serum. 
     
     
         18 . The method of  claim 13  wherein the sample is milk. 
     
     
         19 . A kit for the detection of an immune response to a paratuberculosis-specific antigen in a subject, comprising:
 a) a paratuberculosis-specific antigen from  M. paratuberculosis  strain JTC303; and   b) an anti-immunoglobulin antibody that is specific for the subject.   
     
     
         20 . The kit of  claim 19  further comprising an absorbing antigen preparation.