Differential antigen recognition by serum antibodies from three bovid hosts of Mycobacterium bovis infection.

Cattle, bison and buffaloes are susceptible to Mycobacterium bovis, the causative agent for bovine tuberculosis. Accurate and timely identification of infected animals is critical for improved management and control of disease in these species. Bovids develop humoral immune responses to M. bovis infection making serological tests attractive for tuberculosis screening. However, optimization and validation of antibody assays designed for various animal species require understanding of antigen recognition patterns in each target host. The objective of this study was to characterize serological reactivity profiles generated by cattle, American bison, and African buffaloes in tuberculosis. Serum samples from M. bovis-infected animals were tested for the presence of IgM and IgG antibodies to MPB70/MPB83 and CFP10/ESAT6 chimeric proteins using Dual-Path Platform technology. All three host species showed IgG responses of higher magnitude and frequency than IgM responses; further, IgM seroreactivity was limited to MPB70/MPB83, whereas IgG antibodies recognized both test antigens. In cattle, the IgM and IgG responses were elicited mainly by MPB70/MPB83, whereas bison and buffaloes showed similar IgG seroreactivity rates for MPB70/MPB83 and CFP10/ESAT6 antigens. The findings demonstrate distinct patterns of predominant antigen recognition by different bovid species in M. bovis infection.