European badgers are a wildlife reservoir of bovine tuberculosis in parts of Great Britain. Accurate diagnosis of tuberculosis in badgers is important for the development of strategies for the control of the disease. Sensitive serological tests for badger TB are needed for reasons such as cost and simplicity. Assay of mucosal IgA could be useful for diagnosing respiratory pathogens such as Mycobacterium bovis and for monitoring the response to mucosal vaccination. To develop an IgA assay, we purified secretory IgA from badger bile, identifying secretory component (SC), heavy chain (HC) and light chain (LC), at 66, 46 and 27 Kda, respectively, on the basis of size comparison with other species. Monoclonal antibodies (mAbs) were generated to purified IgA.We selected two for ELISA development. The detection limit of the IgA-specific mAbs was found to be approximately 20 ng/mL when titrated against purified badger bile. One monoclonal antibody specific for badger IgA was used to detect IgA in serum and tracheal aspirate with specificity to an immunodominant antigen of M. bovis. An M. bovis infection dose-dependent IgA response was observed in experimentally infected badgers. IgA was also detected by immunohistochemistry in the lungs of bTB-infected badgers. With further characterisation, these represent new reagents for the study of the IgA response in badgers.
Bibliographical noteFunding Information:
This research was funded by Department for Environment, Food and Rural Affairs, grant number SE3213. All animal work was conducted under A(SP)A licences PPL 70/5965 (UK captive badger work) and PPL 70/6183 (mAb production). We thank Eamonn Gormley (University College Dublin) for supplying serum and tracheal aspirate samples from experimentally infected badgers. We thank staff of the Reagent Production Unit (APHA) and members of the Badger Team and Animal Services Unit past and present for their assistance with laboratory and animal procedures.
Funding: This research was funded by Department for Environment, Food and Rural Affairs, grant number SE3213.
© 2019 by the authors.
- Immunoglobulin A