In a paradigm-breaking study, researchers have discovered a novel way the immune system, specifically Tcells, attack their target cells, reshaping long-held assumptions in immunology and demonstrating direct implications for the field of cancer immunology and bone marrow transplantation. The team consists of Dr. Pavan Reddy, director of the Dan L Duncan Comprehensive Cancer Center at Baylor College of Medicine (BCM) and his team, in collaboration with Drs. Arul Chinnaiyan, S P Hicks Endowed Professor of Pathology, and Marcin Cieslik, assistant professor of pathology, both from University of Michigan Rogel Cancer Center. The study is published in Nature Immunology.
Rewriting the rules of T cell biology The immune system relies on molecules called major histocompatibility complexes (MHC) to detect external “threats” to the body, including from cancerous or foreign (allogeneic) cells. Historically, MHC class I molecules were believed to present signals only to CD8+ T cells (“killer” T cells), while MHC II activated CD4+ T cells (“helper” T cells). This division of MHC class roles guided decades of immunology and cancer research.
In an example of collaborative work, Reddy’s graduate students Emma Lauder and Meng-Chih Wu from BCM and Chinnaiyan and Cieslik’s student Mahnoor Gondal, from University of Michigan, worked with colleagues on various components of the work that spanned several years. The work challenges this foundational MHC class-restricted dichotomy and reveals a previously unrecognized role for the class I pathway in CD4+ T cell–mediated immune defense.