Gr-1dimCD11b+ immature myeloid-derived suppressor cells but not neutrophils are markers of lethal tuberculosis infection in mice.

Tuberculosis (TB) disease may progress at different rates and have different outcomes. Neutrophils have been implicated in TB progression; however, data on their role during TB are controversial. In this study, we show that in mice, TB progression is associated with the accumulation of cells that express neutrophilic markers Gr-1 and Ly-6G but do not belong to conventional neutrophils.

In mice, tuberculosis progression is associated with intensive inflammatory response and the accumulation of Gr-1 cells in the lungs.

Background: Infection with Mycobacterium tuberculosis (Mtb) results in different clinical outcomes ranging from asymptomatic containment to rapidly progressing tuberculosis (TB). The mechanisms controlling TB progression in immunologically-competent hosts remain unclear.

Methodology/principal Findings: To address these mechanisms, we analyzed TB progression in a panel of genetically heterogeneous (A/SnxI/St) F2 mice, originating from TB-highly-susceptible I/St and more resistant A/Sn mice.