医学免疫学：T淋巴细胞介导的细胞免疫应答.pptVIP

初始、效应和记忆T细胞的功能特征 功能特征 初始T细胞 效应T细胞 记忆T细胞 抗原特异性细胞的频率 低 高 高 寿命 短 短 长 效应功能 IL-2 迅速产生效应细胞因子 迅速产生效应细胞因子 归巢 淋巴样组织 淋巴样和非淋巴样组织 淋巴样和非淋巴样组织 多样性 无 功能和归巢多样性 中央型和效应型记忆细胞 免疫记忆具有特异性 Time After Immunization Antigen A Antigen A + Antigen B Secondary anti- A response Primary anti-B response Primary anti-A response 细胞免疫应答的基本过程 * 小 结 T细胞识别的MHC限制性 免疫突触的概念 T细胞活化的双信号 效应T细胞的功能及其作用机制 * Upon activation of na?ve cd4 cells, a heterogeneous population of cells is induced which will depend on the conditions of activation Under ‘neutral’ conditions activated CD4+ T cells which we have termed bi-potential can produce Th1 or Th2 type cytokines depending on the subsequent conditions of their stimulation. Naive CD4+ cells activated under polarizing Th1 conditions induce a population of cells which we have termed Th1 lineage cells. Such cells are made up of two distinct populations. One population of cells are fully differentiated IFN-g producing cells which have a relatively limited capacity to develop into long-term memory cells but mediate effector function. In addition, a population of cells that do not yet have mRNA or protein for IFN-g but have other markers associated with Th1 cells and have the capacity to develop into IFN-g producing cells following activation. we believe that such cells this population that do not yet produce IFN-g are the main population that has the potential to become a resting memory cell Once these resting memory cells are exposed to antigen andIL-12 a proportion of them will become IFN-g producing cells, mediate their effector function and subsequently die. This model is in contrast to CD8 cells which have the capacity to more effeciently develop into memory cells from effector cells. Thus, in terms of vaccines for diseases requiring Th1 responses, a vaccine that induces a high frequency of only CD4+/IFN-g producing cells might be effective for short-term protection but not for long-term memory. This underscores the factg that live attenuated vaccines are the