Infection with Mycobacterium tuberculosis (Mtb), the bacterium that causes tuberculosis (TB), infects an estimated 25% of the world’s population. Most people infected (90%) with Mtb are asymptomatic (called latent infection) and able to control the infection for their lifetime. However, some people will develop symptoms of active TB and spread it to others. The stages of Mtb infection are complex and not well understood. The immune system playsa key role in controlling infection from Mtb so it is no surprise that HIV/AIDS is the most common risk factor for severe forms of TB. The Lin lab is focused on key factors in the pathogenesis of Mtb infection as well as the host pathogen interaction during HIV-TB co-infection. The lab has focused on understanding the specific immune factors involved in controlling early infection and maintenance of latent infection such as TNF and important immune cell types (e.g., CD4 and CD8 T cells). These studies have been extended to address how HIV impairs the Mtb-specific immune responses during co-infection and to what extent these immune responses can be corrected with HIV medications. While HIV infection can now be controlled (but not cured) with potent antiretroviral drugs, patients on these medications are still at greater risk for TB. Ultimately the long term goal in the lab is to better understand the pathogenesis of TB disease during HIV-TB co-infection and develop novel methods of prevention and treatment against these two synergistic pathogens. Dr. Lin has also been involved in the epidemiologic surveillance of invasive Streptococcus pneumoniae in children. Streptococcus pneumoniae is a common bacteria that causes ear infection and pneumoniae in children. Before the advent of the pneumococcal conjugate vaccines, it was a common cause of meningitis and sepsis in young children. Dr. Lin is involved in a nationwide, multicenter surveillance consortium that follows the epidemiology of invasive cases in children.