A leader in global health and former consultant to the White House, Dr. Barry Bloom continues to pursue research on understanding mechanisms of protection against tuberculosis, a disease that claims more than two million people each year. As an investigator in a Gates Grand Challenge grant with Professor David Edwards of the School of Engineering and Applied Research, he is applying nanoparticle technology to deliver vaccines against experimental tuberculosis without the need for needles using an aerosol route. In collaboration with colleagues at UCLA they are elucidating a novel antimicrobial killing mechanism that exists in human macrophages and is effective against the tubercle bacillus. This mechanism is not oxygen or nitrogen radical related, but is vitamin D dependent, which could explain the greater susceptibility of people of African and Asian descent to tuberculosis.