Immunological basis for reactivation of tuberculosis in mice

In this study different inbred strains of mice appeared to control and cont ain a low dose aerosol infection with Mycobacterium tuberculosis in a simil ar manner, giving rise tu a chronic state of disease. Thereafter, however, certain strains gradually began to show evidence of regrowth of the infecti on, whereas others consistently did not. Using C57BL/6 mice as an example o f a resistant strain and CBA/J mice as an example of a strain susceptible t o bacterial growth, we found that these animals revealed distinct differenc es in the cellular makeup of lung granulomas. The CBA/J mice exhibited a ge nerally poor lymphocyte response within the lungs and vastly increased dege nerative pathology at a time associated with regrowth of the infection. As a possible explanation for these events, it was then observed that the CBA/ J mouse strain was also less able to upregulate adhesion molecules, includi ng CD11a and CD54, on circulating lymphocytes. These results therefore sugg est that a failure to control a chronic infection with M. tuberculosis may reflect an inability to localize antigen-specific lymphocytes within the lu ng.