Abstract

Antibodies specific to the cell surface antigens of Mycobacterium avium subsp. paratuberculosis (MAP) have multiple useful applications, e.g. organism detection, immunoconcentration, and cell visualization. The aim of this study was to produce and compare polyclonal antibodies for such research and diagnostic purposes. Three polyclonal antibodies to MAP were produced using sera from immunized rabbits and chickens plus naturally infected cows. Cross-reactive antibodies in each MAP antibody preparation were removed by absorption with heterologous mycobacterial and non-mycobacterial cells. The specificity of each resulting polyclonal antibody preparation was evaluated by ELISA to multiple bacterial cell wall extract antigens. After absorption, chicken anti-MAP IgY had the highest specificity of the three antibody preparations. FITC-labeled anti-MAP IgY was used to effectively locate MAP in macrophages 12 h post-infection. Also, immuno- magnetic beads coated with anti-MAP IgY enhanced recovery of MAP from bacterial suspensions in comparison with non-antibody coated beads. Anti-MAP IgY provides a novel new reagent with broad diagnostic and research applications requiring specific concentration, detection, and quantification of MAP.

• Keywords: M. paratuberculosis; polyclonal antibodies for diagnostic purposes; absorption; anti-MAP IgY