博士学位是高级研究学位，旨在反映与候选人担任独立研究科学家的能力一致的培训水平。这涉及成功完成反映现代免疫学知识的课程工作，并具有进行可发表质量研究的证明能力。要获得该学位的资格，每个候选人都必须成功地获得候选人资格，根据他/她的原始研究提交令人满意的论文，并在期末口试中成功地为其辩护。博士学位论文应包含大量的原始研究成果，其数量应与在经认可的参考期刊上发表的两三篇论文相适应。通常，这些手稿中至少有一份应在考试时被接受出版。<br> <br>免疫系统的艰巨任务是应对环境中各种病原体。一旦暴露于病原体，免疫
The Department of Immunology offers graduate programs leading to the Master of Science and Doctor of Philosophy degrees in a wide range of immunological disciplines. These disciplines include molecular mechanisms of lymphocyte development and selection, T-cell and B-cell receptors, cell interactions, growth factor receptors, cytokine networks, antigen processing and presentation, signal transduction in lymphocytes, V(D)J recombination, anergy, apoptosis, transgenic and knock-out models, immuno-targeting and vaccine design, autoimmunity, AIDS, diabetes, and transplantation.<br>The department provides a common forum for investigators in many areas of U of T and an interdisciplinary research experience in immunology. Members and students in the department are located at the Medical Sciences Building, at the Ontario Cancer Institute, and at the Research Institutes of Mt. Sinai Hospital, Toronto General Hospital, Toronto Western Hospital, The Hospital for Sick Children, and Sunnybrook Hospital. The PhD degree is an advanced research degree intended to reflect a level of training consistent with the ability of the candidate to function as an independent research scientist. This involves successful completion of course work reflecting a knowledge of modern immunology, as well as a demonstrated ability to carry out research of publishable quality.<br>The immune system has the daunting task of dealing with an amazing array of pathogens in our environment. Upon exposure to a pathogen, the innate arm of the immune system is engaged non-specifically. This is an important initial step in clearing the pathogen, however, adaptive immunity is required to generate a highly specific and efficient means of clearing the pathogen. The adaptive immune system is comprised of B and T lymphocytes that express receptors with remarkable diversity tailored to recognize aspects of particular pathogens, or antigens. B and T lymphocytes circulate in the blood and lymph and home to specialized lymphoid organs such as the spleen and lymph nodes. In these locations, inexperienced or nave lymphocytes scan for the presence of antigens. During an infection, dendritic cells which act as sentinels in the peripheral tissues pick up pathogens in the form of antigenic determinants. These antigens are then presented to T lymphocytes within the lymphoid tissues. T lymphocytes of the appropriate specificity respond robustly to the antigen, and either kill the pathogen directly or secrete cytokine mediators that will encourage a B lympohocyte response. B lymphocytes provide humoral immunity by secreting antibodies specific for the pathogen. In the case of both B and T cells, as the immune response contracts, a small number of antigen-specific cells survive so that if re-exposure to the pathogen occurs, a more robust and rapid immune response can take place. This is termed immunological memory and it is what is conferred upon vaccination.