Submitted to: Journal of Leukocyte Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/1998
Publication Date: N/A
Interpretive Summary: Mycobacterium bovis is the organism that causes most cases of tuberculosis in animals. Because this organism can also infect humans, the presence of tuberculosis in animals is considered a public health threat. A better understanding of the interaction between animals and M. bovis is needed so that improved diagnostic tests and vaccines for tuberculosis can be developed. In this study, mice with specific deficiencies in the immune system were given M. bovis. We determined that immune cells, referred to as CD8 T cells, are important for development of a protective immune response. Other cells also are involved in protective immune responses, but additional research is needed to more fully understand their role. These results will be used for by scientists to develop a more complete understanding of the immune responses animals develop against M. bovis. Improved methods for diagnosis and control of tuberculosis will be developed as more is learned about the interaction between the organism an host.
Technical Abstract: The role of various effector T-cell populations in the bovine immune response to Mycobacterium bovis infection is poorly understood. This is largely due to the difficulties associated with performing in vivo challenge studies in the natural host species. In this report, we utilized a fetal bovine-severe combined immunodeficient (SCID-bo) xenochimeric mouse emodel to study the protective role of two putative effector cell types, CD8+ T-cells and a subpopulation of gamma/delta T-cells that express WC1, a member of the cysteine-rich scavenger receptor superfamily (CRSR). We demonstrate that CD8+ T-cells play a key role in protection and contribute substantially to bovine IFN-gamma mRNA levels at 30 days post infection. The role of WC-1 bearing cells to protection was less definitive, but our results suggest that this population may play a pivotal role early in infection. Granuloma architecture was altered in anti-WC1 (ILA29) but not anti-CD8 (ILA51) treated animals, suggesting that this population may be involved in recruitment of various cell types to sites of infection.