Autumn Sanders

Tuberculosis is caused by Mycobacterium tuberculosis, a bacterium that has infected humans for thousands of years. When it spreads from the lungs to the central nervous system, people develop tuberculous meningitis, the most severe form of tuberculosis. The severity of tuberculous meningitis depends on the inflammatory response in the cerebrospinal fluid. Host factors contribute to the inflammatory response, but the role of bacterial factors is not understood. Lipoproteins may be a bacterial factor because they interact with the immune system, but the role of lipoproteins in the inflammatory response to tuberculous meningitis is also not understood. Here we show that a strain of Mycobacterium tuberculosis with mutations in lppT, a gene that encodes a probable lipoprotein, induces lower production of tumor necrosis factor-ɑ than strains without mutations in lppT. LppT has the structure of a lipoprotein and interacts with membrane proteins. Mutations in lppT are common in Central and East Africa and in lineage 4.6.1. LppT may be a bacterial factor that plays a role in the inflammatory response to tuberculous meningitis.