Much of the resurgence of tuberculosis during the past decade can be attributed to the fast spread of new bacterial strains that are resistant to the conventional anti-tuberculosis drugs. New therapeutic strategies are urgently needed, requiring a better understanding of the interaction of the causal agent, Mycobacterium tuberculosis, with the host cells. Monocyte/macrophages are the principal targets for mycobacterium. These cells possess a powerful intracellular killing mechanism and play an essential role in the clearance of bacteria. However, one of the major features of tuberculosis pathogenesis is the residency of bacteria in an intracellular vacuole that evades intracellular killing. Mycobacterium tuberculosis interacts with specific cell surface molecules, acting as ""an entrance gate"" and ultimately producing factors that inhibit the intracellular killing. Dr. Zakaria Hmama's research focuses on the molecular mechanisms regulating the entry of the bacteria into macrophages and the resistance to intracellular killing. Such studies will provide a rational basis for the development of new drug strategies.