Correlation between lymph node pathology and chemokine expression during bovine tuberculosis

Bovine tuberculosis is a disease of worldwide importance yet comparatively little is known about chemokine responses to infection. We report on the levels of chemokine expression within lymph nodes of cattle infected with Mycobacterium bovis when infection would be well established. Expression levels of a number of chemokines were increased in infected cattle and could be correlated to levels of respective chemokine receptors. Several chemokines were significantly correlated to pathology within the lymph node, indicating a direct relationship between chemokine expression and disease. Vaccinated animals challenged with M. bovis had lower levels of chemokine expression than unvaccinated, challenged animals, correlating with lower levels of disease in vaccinated animals. The chemokine expression profile correlated with previous evidence for a pro-inflammatory bias within the lymph node. At this stage of infection we suggest there is on-going chemokine expression by cells associated with the granuloma and continual recruitment of cells to control infection.