Dr. Metelitsa’s research is focused on understanding the role of Vα24-invariant natural killer T cells (iNKTs) in tumor immunity. Using clinical samples from neuroblastoma patients, his lab demonstrated for the first time that iNKTs localize to primary tumors and their presence at the tumor site is associated with good outcome. In the pursuit of the underlying mechanistic basis for the observed association between iNKTs and clinical outcome, Metelitsa’s group has published a series of high-impact papers that revealed the mechanisms of iNKT cell tumor localization and function in the tumor microenvironment. In one of these studies, they discovered the mechanism by which iNKTs attack tumor-associated macrophages (TAMs). That study has had a major impact in the fields of NKT cell and neuroblastoma research. First, it explained how iNKTs can mediate antitumor activity against CD1d-negative tumors, the majority of solid tumors in humans. Second, it showed for the first time that macrophages infiltrate primary tumors in a subset of neuroblastoma patients, their products directly support tumor growth, and their presence at the tumor site is associated with poor clinical outcome. Three years later a large international study validated this discovery using large independent cohorts of patients, concluding that the presence of M2-like macrophages is associated with a novel inflammatory signature in neuroblastoma that serves as an independent prognostic factor of extremely poor outcome. Most recently, Dr. Metelitsa has been focused on the development of therapeutic applications using iNKTs and their synthetic ligands.