Wu Catherine J, Biernacki Melinda, Kutok Jeffery L, Rogers Shelby, Chen Linyun, Yang Xiao-Feng, Soiffer Robert J, Ritz Jerome
Division of Hematologic Malignancies, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
Clin Cancer Res. 2005 Jun 15;11(12):4504-11. doi: 10.1158/1078-0432.CCR-05-0036.
Donor lymphocyte infusion (DLI) reliably induces durable remission in 75% to 80% of patients with relapsed chronic myelogenous leukemia (CML) following allogeneic bone marrow transplantation. We previously reported the identification of a high titer-specific immunoglobulin G response against two novel leukemia-associated antigens, CML28 and CML66, which correlated with immune-induced remission. The present studies characterize expression of CML28 and CML66 in primary hematopoietic tissues.
Specific monoclonal antibodies to CML28 and CML66 were developed and used to detect antigen expression in leukemia cell lines and primary leukemia tissue on Western blot and immunohistochemistry. Expression patterns were confirmed by antigen-specific real-time PCR.
Both CML28 and CML66 were highly expressed in leukemic blasts from patients with acute myelogenous leukemia and CML blast crisis but barely detectable in normal bone marrow, normal peripheral blood, or leukemic cells from patients with stable-phase CML. In contrast, purified CD34+ progenitors from normal individuals and patients with stable-phase CML expressed high levels of CML28 and CML66 transcript and protein. Immunohistochemical staining for CML66 confirmed rare staining of myeloid precursors in normal marrow and diffuse staining of myeloblastic cells in acute myelogenous leukemia and blast crisis CML marrows.
The expression patterns of CML28 and CML66 are strikingly similar and suggest that antigen expression may play a role in shaping the post-DLI antibody repertoire. The CD34+ restricted pattern of expression of CML28 and CML66 is particularly relevant in light of the notion that DLI likely exerts its curative effect by targeting antigens present in self-renewing malignant progenitor populations in CML.
供体淋巴细胞输注（DLI）能可靠地使75%至80%的异基因骨髓移植后复发的慢性粒细胞白血病（CML）患者获得持久缓解。我们之前报道过鉴定出针对两种新型白血病相关抗原CML28和CML66的高滴度特异性免疫球蛋白G反应，这与免疫诱导的缓解相关。本研究对CML28和CML66在原发性造血组织中的表达进行了特征分析。
研发了针对CML28和CML66的特异性单克隆抗体，并用于在蛋白质印迹法和免疫组织化学检测白血病细胞系及原发性白血病组织中的抗原表达。通过抗原特异性实时聚合酶链反应确认表达模式。
CML28和CML66在急性髓系白血病患者及CML急变期的白血病原始细胞中均高表达，但在正常骨髓、正常外周血或稳定期CML患者的白血病细胞中几乎检测不到。相反，正常个体和稳定期CML患者的纯化CD34+祖细胞表达高水平的CML28和CML66转录本及蛋白。CML66的免疫组织化学染色证实正常骨髓中髓系前体细胞染色罕见，而在急性髓系白血病和CML急变期骨髓中的原始粒细胞呈弥漫性染色。
CML28和CML66的表达模式惊人地相似，提示抗原表达可能在塑造DLI后的抗体库中发挥作用。鉴于DLI可能通过靶向CML中自我更新的恶性祖细胞群体中存在的抗原发挥其治疗作用这一观点，CML28和CML66的CD34+限制性表达模式尤为重要。
