BCR-ABL融合蛋白是CML细胞性特异抗原，也是CML DC疫苗的理想靶抗原。外源性白血病相关抗原在DC细胞内交叉递呈是诱导白血病特异性CTL应答的关键，但现有抗原负载系统不能有效激活DC细胞交叉递呈潜能，限制了DC疫苗抗白血病效能。胞质转导肽（CTP）具高效转导潜能和显著胞质定位特性，可将外源性抗原定位于胞质而实现“内源化”，而外源性抗原“内源化”是激活递呈潜能的前提。故我们提出“借CTP实现外源性BCR-ABL抗原交叉递呈以诱导CML特异性CTL应答”设想。拟通过表达纯化CTP-BCR-ABL融合蛋白并将其转入DC细胞，观察其在胞内的转导活性、亚细胞定位、交叉抗原递呈水平及其在体内外激活BCR-ABL特异性CTL应答的效应。本研究首次以DC细胞为基础，借CTP实现外源性BCR-ABL抗原交叉递呈，激活CML特异性CTL应答，有生物安全性好、靶抗原理想和增强DC细胞交叉递呈潜能等优势。

BCR-ABL fusion protein is a leukemia-associated antigen that is indispensable for CML cell survival, and is thus an ideal target antigen for DC vaccine against CML. While cross-presentation of exogenous leukemia-associated antigen in DC is key to the induction of leukemia-specific CTL response, the present antigen-loading system can’t efficiently activate the cross-presentation potential of DC, resulting in limited efficacy of DC vaccine in anti-leukemia therapy. Cytoplasmic transduction peptide (CTP), a transduction peptide with highly-efficient transduction potential and significant cytoplasmic localization preference, can accomplish the “internalization” of exogenous antigens through its preference of cytoplasmic localization. The “internalization” of the exogenous antigen is a prerequisite for the activation of cross-presentation potential. Therefore, we put forward the research assumption of “inducing CML-specific CTL response via the accomplishment of cross-presentation of exogenous BCR-ABL antigen with CTP”. Through prokaryotic expression and purification of the CTP-BCR-ABL fusion protein, we intend to observe its transduction activity, subcellular localization and cross-presentation in DC, and the in vitro and in vivo BCR-ABL-specific CTL response activated by the DC vaccine. This novel DC-based strategy of “activating the CML-specific CTL response via the accomplishment of cross-presentation of exogenous BCR-ABL antigen through CTP” shows great advantages in good biological safety, efficient activation of the cross-presentation potential of DC, and ideal target antigen.