This could be explained by the different level of vessel permeability between the meninges and the brain parenchyma or simply the available space for structures to expand.19 Injecting TB into the piriform cortex of nonimmunized mice causes local glial activation, but no lymphocyte infiltration, which is in line with previously reported experiments (figure e-3).20 Furthermore, we found that MOG immunization was necessary for the focal brain lesions to develop. This evidence concerns the gene MOG and tuberculosis.