Current Research and Scholarly Interests
Dr. Weissman directs a research group consisting of graduate students, medical student-scientists, and postdoctoral fellows, all of whom study stem cell biology and regenerative medicine, including immunological tolerance. He has trained and supervised hundreds of students and fellows, authored more than 950 scientific articles and has numerous awards and honorary degrees for his research accomplishments. He is an elected member of the National Academy of Sciences, the Institute of Medicine, the American Academy of Arts and Sciences, the Amerian Philosophical Society, and many other societies. He is past president of the American Association of Immunologists  and the International Society of Stem Cell Research . Dr. Weissman is an expert in the field of hematopoiesis, leukemia, and hematopoietic stem cells [HSC], and most recently, the clonal events leading from HSC to leukemia stem cells.. His research also encompasses the phylogeny and developmental biology of the cells that make up the blood-forming and immune systems. He has a laboratory at Hopkins Marine Station of Stanford University, where he studies the histocompatibility systems in a colonial protochordate, a system which he proposed evolved to prevent predatory germline stem cell lineages from passing from one individual to another in multi-individual colonies that share a common extracorporeal blood vascular system; only histocompatible stem cells can colonize allogeneic natural parabionts. His laboratory was first to identify and isolate the blood-forming stem cell [HSC] from mice, and has defined, by lineage analysis, the stages of development between the stem cells and mature progeny. His laboratories have also discovered the human HSC, a human brain-forming stem cell population, mouse skeletal muscle stem cells, and an osteochondral stem cell in mice. He has worked in the area of cancer since 1977, and is a leader in the field of cancer stem cell biology. In recent years his work has included studying the potential of CD47 as a cancer therapeutic and identifying cancer stem cells from a variety of blood and solid cancers. He and his colleagues have found that CD47, a don't eat me signal is highly expressed beginning in the latter stages of progression of cancer stem cells from the benign to the highly malignant state, and this counteracts eat me signals on preneoplastic and highly malignant cancer cells, presumably as part of the evolution of cancer clones driven by self-renewing subsets of cells in the cancer. This research brings into focus the primary role of phagocytic cells such as macrophages of the innate immune system, in tumor surveillance. Dr. Weissman was a founder of SyStemix, Cellerant, and Stem Cells, Inc., all focused on bringing stem cell therapies into the clinic, and earlier was on the founding SABs of Amgen, DNAX, and T Cell Sciences; the CD47 work led to the founding of Forty Seven, Inc, Bitterroot Bio, Pheast, and Forty Eight, Inc.