Although these various studies use similar mouse (C57BL/6) and M. tuberculosis (H37Rv strain) genetic backgrounds, there are some experimental differences that may account for the distinct results: the infection route (aerosol versus intranasal), the dose of bacteria in infection (low versus high), the time points chosen for the analyses, the inactivating mutations in the Il1b gene, and the use of genetic abrogation versus antibody neutralization. Here, IL1B is linked to infection.