- B cell developmentB lymphocytes produce antibodies and present antigens. They are essential components of the immune response. Failure to regulate the growth, development and response of B cells can lead to malignancy, immunodeficiency and autoimmunity. Our research efforts are directed towards a better understanding of the process of B cell commitment and the events that allow progression along the B cell pathway. Cellular, biochemical and molecular techniques are utilized to achieve our research aims.
- Understanding biochemical and cellular checkpoints during lymphoid developmentWe have developed a number of in vitro assays over the years that allow for the careful examination of the stages of B cell lineage development from multipotent stem cells to fully functional, antibody secreting, plasma cells. We have identified a number of key features and mechanisms of action that mark transitions between stages and defined checkpoints that can result in positive and negative selection. Amongst our current interests are: the role of the peptide HK1 (a member of the tackykinin family) in regulating early events in the B lineage pool; a potential mechanism for abrogating IL-7 responsiveness based on downstream induction of SOCS proteins; and a novel role for IL-21 in accelerating B cell development. Our interest in these projects is driven not only by the desire to understand the role of these molecules in normal development but also because the aberrant regulation of any of these can have direct consequences on immune-regulated disease.
- Immune system and diseaseIncreased understanding of the immune response and, in particular, the biochemical pathways that regulate immunity provide the basis for renewed efforts to develop cancer vaccines. We have developed a syngeneic cell-based anti-leukemia murine model focused on the expression of IL-12 derived from lentiviral transductions. In that work we showed that syngeneic leukemia cells expressing IL-12 can induce protective, long-lasting and specific immunity. Of interest for clinical application, we also demonstrated that as few as 0.5% of the leukemia cells have to express IL-12 to achieve immunity, as long as each cell produces IL-12 above a certain threshold. Once initiated, the immune response it is effective against all of the leukemia cells, including those that do not express IL-12. Using in vivo and in vitro culture systems we are determining the cells required to initiate immunity and target and kill leukemia cells. This work is being extended to solid tumours as well. In addition, these techniques are now being modified using primary human leukemia cell blasts from AML, ALL, CML, and CLL in experiments which form the basis for subsequent human clinical trials.
Senior Scientist, Princess Margaret Cancer Centre
Professor, Departments of Medical Biophysics and Immunology, University of Toronto
Ronald Buick Chair in Cancer Research