COUNTERMEASURES TO PREVENT AND CONTROL TUBERCULOSIS IN CATTLE AND WILDLIFE RESERVOIRS
Location: Infectious Bacterial Diseases Research Unit
Title: Immune Responses in Cattle Inoculated with Mycobacterium bovis, Mycobacterium tuberculosis, or Mycobacterium kansasii
Submitted to: Clinical and Vaccine Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 4, 2009
Publication Date: February 1, 2010
Citation: Waters, W.R., Whelan, A.O., Lyashchenko, K.P., Greenwald, R., Palmer, M.V., Harris, N.B., Hewinson, R.G., Vordermeier, H.M. 2010. Immune Responses in Cattle Inoculated with Mycobacterium bovis, Mycobacterium tuberculosis, or Mycobacterium kansasii. Clinical and Vaccine Immunology. 17(2):247-252.
Interpretive Summary: Despite highly successful eradication efforts in several countries, tuberculosis of cattle remains a serious health concern worldwide. In addition, recent outbreaks of tuberculosis in Michigan, Minnesota, California, Texas, and New Mexico demonstrate that the disease is far from eliminated from the United States. Improved techniques are needed for detection of infected cattle. To develop improved tests, it is beneficial to first understand the immune response to infection. In this study, specific host responses of cattle to bovine tuberculosis infection were determined and compared to responses by cattle infected with two other similar bacteria. Results from this study demonstrate that additional tools will need to be developed to differentiate infection with these three bacteria. Also, present findings demonstrate the potential for cattle to be used as a latency model for human tuberculosis. Knowledge obtained from this study will enable more accurate detection of cattle with tuberculosis.
Cattle were inoculated with Mycobacterium bovis, Mycobacterium tuberculosis, or Mycobacterium kansasii to compare antigen-specific immune responses to varied patterns of mycobacterial disease. Disease expression ranged from colonization with associated pathology (M. bovis), colonization without pathology (M. tuberculosis), to no colonization or pathology (M. kansasii). Delayed type hypersensitivity and interferon-gamma responses were elicited by each mycobacterial inoculation; however, responses by M. bovis- and M. tuberculosis-inoculated animals exceeded those of M. kansasii-inoculated animals. Specific antibody responses were detected in all M. tuberculosis- and M. bovis-inoculated cattle three wks after inoculation. From 6 – 16 wks after M. tuberculosis inoculation, antibody responses waned whereas responses persisted with M. bovis infection. With M. kansasii inoculation, initial early antibody responses waned by 10 wks after inoculation and then increased 2 wks after injection of purified protein derivative for skin test at 18 wks after challenge. These findings indicate that antibody responses are associated with antigen burden rather than pathology, cellular immune responses to tuberculin correlate with infection but not necessarily with pathology or bacterial burden, and exposure to mycobacterial antigens may elicit an antibody response in a pre-sensitized animal.