James Edgar Till (1931– )

James Edgar Till (1931– )

James Edgar Till is a biophysicist known for establishing the existence of stem cells along with Ernest McCulloch in 1963. Stem cells are undifferentiated cells that can shift, or differentiate, into specialized types of cells and serve as a repair system in the body by dividing indefinitely to replenish other cells. Till’s work with stem cells in bone marrow, which produces the body’s blood cells, helped form the field of modern hematology, a medical discipline that focuses on diseases related to the blood. He also worked on issues in the medical field including patient inclusion in clinical trials, matters of effective and ineffective clinical communication, and limitations of public access to medical and scientific research. Till’s work with stem cells furthered scientists’ understanding of abnormal blood cell development, which helped set the foundation for regenerative medicine.

Till was born in Saskatchewan, Canada, on 25 August 1931, but was raised near the Alberta side of the provincial border town of Lloydminster in Canada. As a child, Till lived on a farm and manually harvested crops, work that he performed for sixteen hours per day. Grain harvesting machines only came into common practice during his teenage years, so the farm work Till did as a child involved a lot of manual labor. After his childhood, Till frequently visited his family’s farm in Lloydminster and helped with the harvest there each fall.

After graduating high school, Till pursued his higher education in physics. He attended the University of Saskatchewan in Saskatchewan, Canada, with scholarships from the Standard Oil Company and the National Research Council for academic merit, and he graduated with a bachelor of science degree in 1952 and a master of science degree in 1954. Till completed his master’s degree in physics under the supervision of Harold Elford Johns, a scientist who had discovered that ionizing radiation, which is radiation that removes electrons from atoms, could be used as a cancer treatment. Till later secured a fellowship position at the National Cancer Institute of Canada, or NCIC, modernly known as the Canadian Cancer Trials Group, where he explored how radiation affects cells in mammals. Till’s fellowship at the NCIC gave him the chance to pursue further graduate studies, later completing his doctoral studies in biophysics at Yale University in New Haven, Connecticut, in 1957. During his doctorate, Till studied the effects of radiation on cell division in mammals.

In 1957, Till accepted a position located in Toronto at the Ontario Cancer Institute’s Physics Division, where he met McCulloch, who studied blood and blood diseases. Till and McCulloch’s research partnership in the late 1950s and early 1960s led to their eventual collaboration on stem cell research. Till and McCulloch formally collaborated in 1958 when McCulloch began performing experiments that involved exposing mice bone marrow to radiation to test susceptibility of tissue to radiation. McCulloch’s experiments needed a physicist who knew how to work with radiation to operate the radiating equipment. Till and McCulloch were trying to understand why and under what circumstances radiation therapy killed cancer cells.

Till and McCulloch continued their research with mice and radiation in the 1960s. Scientists had previously theorized that some component in the blood could save people who had radiation sickness. Scientists then realized they could save mice from death caused by radiation by transplanting healthy bone marrow cells into sick mice. That served as the basis to Till and McCulloch’s research. After injecting mice with bone marrow cells, Till and McCulloch noticed small lumps forming in the mice’s spleens. They named those lumps, spleen colonies. Further experiments demonstrated that the colonies were clones derived from single cells, which later scientists identified as stem cells. The pair published their results in the scientific journal Nature in 1963. Additional experiments demonstrated that the colony-forming cells were capable of self-renewal, which is the process by which stem cells divide to create more stem cells. At the time, the technique of bone marrow transplantation was in its early stage and scientists knew that transplantation replenished the essential cells of the blood system. Till and McCulloch’s work shed light on the source of those cells by showing how a single type of cell could proliferate to repopulate bone marrow cells while also specializing into different types of mature blood cells.

In the following decades, Till shifted his focus away from stem cell research. In the 1970s, he collaborated with cancer researchers and published an article on the efficacy of different treatments for a type of throat cancer. Then, in the 1980s, he focused on patient inclusion in clinical trials. Till and colleagues revealed a direction for future research in efficiently preventing barriers to patient entry in clinical trials, which would help apply fundamental science to human disease.

During the 1990s, Till researched issues relating to doctor-patient communication. He discussed the problems facing clinical communication from doctors to patients, including how medical schools lacked effective courses to teach their students how to communicate with dying patients. Till and colleagues published that analysis in the British Medical Journal in 1991. They also questioned how researchers could address the issue of communication between doctors and patients if educational and health care systems do not incentivize health care professionals to learn and teach clinical communication skills. Till claimed that medical school was a stressful and abrasive experience that bred cynicism and callousness among future doctors rather than encouraging empathetic doctors who know how to communicate with terminally ill patients. Till ended the article by stating that such communication education needed to be incorporated into medical education and continuing education programs promptly so that physicians are empowered to provide better medical care for their patients.

Till has achieved several awards and distinctions. He served on numerous national and international committees, including at the University of Toronto in Toronto, Ontario, and the Canadian Cancer Trials Group. In 1994, he became an officer of the Order of Canada, soon becoming a fellow of the Royal Society of Canada and the Royal Society of London. In 2005, he won the Albert Lasker Award, which recognizes contributions to medical science, for basic medical research. Till later founded the Canadian Stem Cell Foundation in Ottawa, Ontario, which researches stem cell derived therapies for clinical benefit.

During the late twentieth century, Till’s list of research topics extended to include quality of life research, clinical and epidemiological studies, research ethics, decision-making behaviors of cancer patients and those at high-risk to develop cancer, and the influence of the internet as a source for information, support, and advocacy. He advocated for public open-access to medical journals to provide medical and research study results to everyone. Because of his advocacy, the California Institute of Regenerative Medicine in Oakland, California, later required that papers published with CIRM funding to be available to the public. Till also was the editor of two blogs, called Be Openly Accessible or Be Obscure and Cancer Stem Cell News.

Till’s research with McCulloch provided the foundation for both modern-day stem cell research and for medical advances to treat cancer and other diseases. Those advances include therapies like bone marrow transplants, which involve the infusion of certain stem cells into the body to restore immune function. Till’s research also provided new opportunities in regenerative medicine, which is a field in which scientists use stem cells to repair or replace damaged or diseased cells to produce artificial organs. As of 2020, Till holds the title of Professor Emeritus at the University of Toronto in Toronto, Canada.


  1. Becker, Andrew J., Ernest A. McCulloch, and James E. Till. "Cytological demonstration of the clonal nature of spleen colonies derived from transplanted mouse marrow cells." Nature 197 (1963): 452–4. https://tspace.library.utoronto.ca/bitstream/1807/2779/2/Nature_1963_197_452.pdf (Accessed August 24, 2020).
  2. Canadian Medical Hall of Fame. "James Till PhD." Canadian Medical Hall of Fame. https://www.cdnmedhall.org/inductees/jamestill (Accessed August 24, 2020).
  3. Dancey, Janet. “New Name–Canadian Cancer Trials Group.” Canadian Cancer Trials Group, 2016. https://www.ctg.queensu.ca/public/new-name-canadian-cancer-trials-group (Accessed August 24, 2020).
  4. He, Shenghui, Daisuke Nakada, and Sean J. Morrison. "Mechanisms of Stem Cell Self-Renewal." Annual Review of Cell and Developmental Biology 25 (2009): 377–406. https://www.annualreviews.org/doi/full/10.1146/annurev.cellbio.042308.113248 (Accessed August 23, 2020).
  5. Johns, Harold Elford, and John Robert Cunningham. The Physics of Radiology. Springfield: Charles T. Thomas Publishers, 1983. http://www.mys1cloud.com/cct/ebooks/978039804669.pdf (Accessed August 23, 2020).
  6. Kuehn, Bridget M., and Tracy Hampton. “2005 Lasker Awards Honor Groundbreaking Biomedical Research, Public Service.” Journal of the American Medical Association 294 (2005): 1327–30. https://jamanetwork.com/journals/jama/article-abstract/201549 (Accessed August 23, 2020).
  7. National Institutes of Health. “5. Hematopoietic Stem Cells.” Stem Cell Information. https://stemcells.nih.gov/info/2001report/chapter5.htm (Accessed August 23, 2020).
  8. Niederer, Jacques V., Nigel V. D. Hawkins, Walter D. E. Rider, and James E. Till. "Failure Analysis of Radical Radiation Therapy of Supraglottic Laryngeal Carcinoma." International Journal of Radiation Oncology, Biology, Physics 2 (1977): 621–9. https://www.redjournal.org/article/0360-3016(77)90041-4/fulltext (Accessed August 23, 2020).
  9. Ross, Langley G., Heather J. Sutherland, Samuel Wong, Salomon Minkin, Hilary A. Llewellyn-Thomas, and James E. Till. "Why Are (or Are Not) Patients Given the Option to Enter Clinical Trials?" Controlled Clinical Trials 8 (1987): 49–59.
  10. Siminovitch, Louis, Ernest A. McCulloch, and James E. Till. "The distribution of colony-forming cells among spleen colonies." Journal of Cellular and Comparative Physiology (1963): 327–36. https://tspace.library.utoronto.ca/bitstream/1807/2778/2/JCP_1963_62_327.pdf (Accessed August 24, 2020).
  11. Simpson, Michael, Robert Buckman, Moira Stewart, Peter Maguire, Mack Lipkin, Dennis Novack, and James Till. "Doctor-Patient Communication: The Toronto Consensus Statement." British Medical Journal 303 (1991): 1385–7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1671610/pdf/bmj00155-0047.pdf (Accessed August 23, 2020).
  12. University of Toronto. “James Edgar Till–CV.” WebArchive. https://web.archive.org/web/20070927015236/http://myprofile.cos.com/tillj16 (Accessed August 24, 2020).
  13. Worton, Ronald G., Ernest A. McCulloch, and James E. Till. "Physical separation of hemopoietic stem cells differing in their capacity for self-renewal." The Journal of Experimental Medicine 130 (1969): 91–103. https://tspace.library.utoronto.ca/bitstream/1807/2775/2/Worton_et_al_JEM_1969_130_91.pdf (Accessed August 24, 2020).
  14. Wu, Alan M., James E. Till, Louis Siminovitch, and Ernest A. McCulloch. "Cytological evidence for a relationship between normal hematopoietic colony-forming cells and cells of the lymphoid system." The Journal of Experimental Medicine 127 (1968): 455–64. https://tspace.library.utoronto.ca/bitstream/1807/2776/2/Wu_et_al_JEM_1968_127_455.pdf (Accessed August 24, 2020).

How to cite

Bains, Ajeet, "James Edgar Till (1931– )". Embryo Project Encyclopedia (2020-11-20). ISSN: 1940-5030 http://embryo.asu.edu/handle/10776/13189.

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Arizona State University. School of Life Sciences. Center for Biology and Society. Embryo Project Encyclopedia.


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People, Experiments, Technologies


Colony-Forming Units Assay; Stem Cell Assays; Hematopoietic Stem Cell Mobilization; Stem Cells, Hematopoietic; Hematopoietic Cell Growth Factor; Tumor Stem Cells; Adult Stem Cell Research; Colony-forming units (Cells); Hematopoietic stem cells; Progenitor cells; Stem cells--Effect of radiation on; Stem cells--Research; People