Immune response to green fluorescent protein: implications for gene therapy.

Green fluorescent protein (GFP) is a widely used intracellular reporter molecule to assess gene transfer and expression. A potential use for GFP is as a co-expressed marker, to select and enrich gene-modified cells by flow cytometry. Processed peptides derived from GFP and presented by the major histocompatibility complex on the cell surface could potentially induce T cell immune responses against GFP+ cells. Thus, clinical application of GFP is premature, since in vivo studies on its immunogenicity are lacking. Therefore, we investigated immune responses against EGFP (enhanced-GFP) in two transplantable murine models: the BALB/c (H-2d) BM185 pre-B leukemia and the C57BL/6 (H-2b) EL-4 T cell lymphoma. BM185 and EL-4 cell lines modified to express high levels of EGFP showed drastic reduction of disease development when transplanted into immunocompetent mice. BM185/ EGFP did lead to rapid development of disease in immunodeficient Nu/Nu mice. Mice surviving BM185/EGFP leukemia challenge developed high cytotoxic T lymphocyte (CTL) responses against EGFP-expressing cells. Furthermore, immune stimulation against BM185/EGFP cells could also be induced by immunization with EGFP+ transduced dendritic cells. The effects of the co-expression of EGFP and immunomodulators (CD80 plus GM-CSF) were also investigated as an irradiated leukemia vaccine. EGFP co-expression by the vaccine did not interfere with the development of CTLs against the parental leukemia or with the anti-leukemia response in vivo. These results indicate that the immune response against EGFP may interfere with its applicability in gene insertion/replacement strategies but could potentially be employed for leukemia cell vaccines.     

CCL3/MIP-1alpha is a potent immunostimulator when coexpressed with interleukin-2 or granulocyte-macrophage colony-stimulating factor in a leukemia/lymphoma vaccine

Chemokines orchestrate trafficking of immune effector cells during inflammation. Here we demonstrate that chemokines also serve to potentiate effector cell-mediated antineoplastic immune responses in vaccination strategies. As a critical mediator of inflammation, macrophage inflammatory protein 1alpha (CCL3/MIP-1alpha) attracts and stimulates both antigen-presenting and cytotoxic cells. In the A20 leukemia/lymphoma vaccine model, we explored the efficacy of MIP-1alpha in combination with interleukin-2 (IL-2) or granulocyte-macrophage colony-stimulating factor (GM-CSF). After subcutaneous injection of the MIP-1alpha + IL-2 or MIP-1alpha + GM-CSF combination vaccine, focal but pronounced infiltrates of CD4+ and CD8+ T cells were observed at the vaccination sites. In mice with preestablished leukemia/lymphoma, survival is significantly improved in animals treated with MIP-1alpha + GM-CSF- and MIP-1alpha + IL-2-secreting vaccines. Protection is superior in the MIP-1alpha + GM-CSF group, with the effects of MIP-1alpha and GM-CSF being synergistic. In contrast, suppression of lymphoblast proliferation by single-immunogen vaccines secreting MIP-1alpha, GM-CSF, or IL-2 alone does not translate to improved survival. The systemic protective effects afforded by the MIP-1alpha + IL-2 or MIP-1alpha + GM-CSF combination are mediated by different effector cell populations. In the MIP-1alpha + IL-2 group, antineoplastic defense is mediated by CD8+ T and NK cells, whereas in the MIP-1alpha + GM-CSF group CD4+ T cells are involved in addition to CD8+ cytotoxic T cells, underscoring that T cell help is critical for long-term protection. Thus combination of MIP-1alpha with different cytokines recruits different sets of effector cells into a potent antineoplastic immune response.     

Anti-tumour activity against B16-F10 melanoma with a GM-CSF secreting allogeneic tumour cell vaccine.

Genetic modification of tumour cells with the GM-CSF encoding gene renders these cells more potent, as autologous tumour cell vaccine, than their wild-type counterparts. However, autologous vaccines are impractical for wide-scale clinical use and we have therefore investigated the efficacy of the GM-CSF genetic modification approach with an allogeneic whole cell tumour vaccine. In this report, we show that the allogeneic K1735-M2 (H-2k) melanoma cell vaccine induces a specific protective anti-tumour response against the syngeneic B16-F10 (H-2b) melanoma tumour in C57BL/6J mice. In vitro T cell work demonstrated that vaccination of animals with the allogeneic cell vaccine generated cytotoxic T cells specific for the autologous tumour. In vivo T cell subset depletion experiments also illustrated that this anti-tumour effect was mediated by both CD4+ve and CD8+ve T cells, suggesting that the allogeneic vaccine may operate through the 'cross-priming' phenomenon whereby tumour antigens are processed and presented to T cells by the host's own antigen presenting cells (APC). Thus, we transduced K1735-M2 cells with a GM-CSF expressing retroviral vector and showed anti-tumour activity of the GM-CSF secreting K1735-M2 cells as a therapeutic vaccine against the syngeneic B16-F10 tumour. Our data imply that GM-CSF genetically modified allogeneic whole cell tumour vaccines could be successful in the clinic. In addition, more potent combination gene therapy strategies could be tested using this therapeutic allogeneic vaccine model.     

Gene transfer of GM-CSF, CD80 and CD154 cDNA enhances survival in a murine model of acute leukemia with persistence of a minimal residual disease

Gene transfer of various cytokines and co-stimulatory molecules has been reported to induce a potent antileukemic immunity in murine models, however, the relative efficiency and possible synergistic effects between candidate genes have not been extensively investigated. We analyzed in a murine model of BCR/ABL acute leukemia whether gene transfer of CD154, CD80 or GM-CSF as a single agent or combination of CD154 + GM-CSF, CD80 + CD154 and GM-CSF + CD80 in leukemic cells could enhance survival. We observed that CD154 gene transfer induced a marked inhibition of leukemogenicity, and also that CD154 and combination of GM-CSF and CD80 gene transfer protected mice against subsequent challenge with leukemic cells and had a therapeutic effect for a pre-established leukemia disease. We also found minimal residual leukemic disease by RT-PCR for 6 to 12 months in 0 to 25% of animals injected with transduced leukemic cells and surviving the challenge without evidence of disease, except in the control empty plasmid group where very few mice survived the challenge but all of those were positive by RT-PCR. These findings suggest that leukemic cell vaccination by gene transfer can induce a tumor dormancy phenomenon compatible with long-term survival.     

酪氨酸激酶抑制剂对CD19 CAR-T细胞在难治/复发Ph阳性急性淋巴细胞白血病中扩增的影响

目的 观察酪氨酸激酶抑制剂(tyrosine kinase inhibitors, TKIs)对CD19嵌合抗原受体修饰（CAR）T细胞在难治/复发Ph+急性淋巴细胞白血病（ALL）中的扩增、疗效及不良反应的影响。方法 收集10例难治/复发Ph+ ALL患者（TKIs组）和16例难治/复发Ph阴性B ALL患者（非TKIs组）,TKIs组给予TKIs口服。在输注CD19 CAR T细胞后第0、4、7、14、21和28天分别检测外周血中CD19 CAR T细胞,分析两组输注后的疗效及不良反应。结果 TKIs组外周血中CD19 CAR T细胞的峰值高于非TKIs组,两组差异有统计学意义（P=0.0037）;两组细胞因子峰值、细胞因子释放综合征（CRS）分级、第14天完全缓解（CR）率、总生存率（OS）和无病生存率（DFS）差异均无统计学意义（P>0.05）。结论 TKIs促进CD19 CAR T细胞在难治/复发Ph+ ALL中的扩增,不抑制CD19 CAR T细胞的疗效,不加重其不良反应,近期及远期疗效肯定。     

Therapeutic HER2/Neu DNA vaccine inhibits mouse tumor naturally overexpressing endogenous neu.

The therapeutic efficacy of HER2/c-erbB-2/neu DNA immunization on mouse tumor cells expressing exogenous human or rat p185neu but not on mouse tumor cells naturally expressing mouse p185neu has been demonstrated. We investigated the feasibility of using N-terminal rat neu DNA immunization on mouse tumor overexpressing endogenous p185neu and enhancing the therapeutic efficacy of this vaccine by fusion to various cytokine genes, including interleukin-2 (IL-2), interleukin-4 (IL-4), or granulocyte-macrophage colony-stimulating factor. In a therapeutic model, N'-neu-IL-2 DNA vaccine was significantly better than N'-neu DNA vaccine, and N'-neu DNA vaccine was significantly better than control DNA or N'-neu-IL-4 DNA vaccine. The therapeutic efficacy of DNA vaccines was correlated with tumor infiltration of CD8+ T cells. Depletion of CD8+ T cells completely abolished the therapeutic effects of N'-neu-IL-2 DNA vaccine and N'-neu DNA vaccine. Depletion of CD4+ T cells after tumor implantation had no influence on N'-neu-IL-2 DNA vaccine, but enhanced the therapeutic efficacy of N'-neu DNA vaccine. Our results demonstrate that rat N'-neu DNA vaccine has a therapeutic effect on established tumor through the CD8+ T-cell-dependent pathway. Depletion of CD4+ T cells or fusion to the IL-2 gene can thus further enhance the therapeutic effects of N'-neu DNA immunization on mouse tumor expressing endogenous p185neu.     

Herpes simplex virus type-1 amplicon vectors for vaccine generation in acute lymphoblastic leukemia

For leukemia vaccine generation, high-efficiency gene transfer is required to express immunomodulatory molecules that stimulate potent antileukemic immune responses. In this context, herpes simplex virus type-1 (HSV-1)-derived vectors have proven to be a promising tool for genetic modification of lymphoblastic leukemia cells. Yet, vector-associated viral protein expression might inadvertently modulate vaccine efficacy facilitating both immune evasion and immune stimulation. To explore the issue of immune-stimulation versus immune-suppression in immature lymphoblastic leukemia cells, two types of HSV-1 amplicon vectors, helper virus-dependent and helper virus-free that express the immunomodulatory molecules CD70 and IL-2, were compared with regard to their vector-associated immunomodulatory potential. We first established that lymphoblastic cell lines and primary acute lymphoblastic leukemia (ALL) cells express HSV receptor genes. Lymphoblastic cell lines were transduced with high efficiency, and in primary ALL cells high gene transfer rates of 47+/-15 and 42+/-14% were obtained with helper virus-dependent and -free HSV-1 amplicon vectors, respectively. The efficacy of the two amplicon vectors to induce antineoplastic responses was assessed in a vaccine setting in mice with pre-existing highly malignant lymphoblastic disease. Treatment of mice with vaccine cells transgenically expressing CD70+IL2 significantly suppressed lymphoblastic cell proliferation and improved survival. Of note, when helper virus-dependent HSV-1 amplicon vectors were used for vaccine preparation, the high immunogenic potential of the vector itself, in the absence of transgenic CD70+IL2 expression, seemed to be sufficient to mediate protection comparable to the antineoplastic response achieved by expression of immunomodulatory molecules. Thus for vaccine generation in B lymphoblastic leukemia, the immunogenic potential of HSV-1 helper virus-dependent amplicon vectors does provide additional benefit to the high transduction efficiency of HSV-1-derived vectors.     

FTY720, a new alternative for treating blast crisis chronic myelogenous leukemia and Philadelphia chromosome-positive acute lymphocytic leukemia

Blast crisis chronic myelogenous leukemia (CML-BC) and Philadelphia chromosome-positive (Ph1-positive) acute lymphocytic leukemia (ALL) are 2 fatal BCR/ABL-driven leukemias against which Abl kinase inhibitors fail to induce a long-term response. We recently reported that functional loss of protein phosphatase 2A (PP2A) activity is important for CML blastic transformation. We assessed the therapeutic potential of the PP2A activator FTY720 (2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol hydrochloride), an immunomodulator in Phase III trials for patients with multiple sclerosis or undergoing organ transplantation, in CML-BC and Ph1 ALL patient cells and in in vitro and in vivo models of these BCR/ABL+ leukemias. Our data indicate that FTY720 induces apoptosis and impairs clonogenicity of imatinib/dasatinib-sensitive and -resistant p210/p190(BCR/ABL) myeloid and lymphoid cell lines and CML-BC(CD34+) and Ph1 ALL(CD34+/CD19+) progenitors but not of normal CD34+ and CD34+/CD19+ bone marrow cells. Furthermore, pharmacologic doses of FTY720 remarkably suppress in vivo p210/p190(BCR/ABL)-driven [including p210/p190(BCR/ABL)(T315I)] leukemogenesis without exerting any toxicity. Altogether, these results highlight the therapeutic relevance of rescuing PP2A tumor suppressor activity in Ph1 leukemias and strongly support the introduction of the PP2A activator FTY720 in the treatment of CML-BC and Ph1 ALL patients.     

三染色-流式细胞术检测急性B淋巴细胞白血病微量残留病的研究

目的 建立三染色－流式细胞术检测微量残留白血病细胞。方法 利用三染色－流式细胞仪检测急性B淋巴细胞白血病患独骨髓中的CD10^ CD22^ CD45^-或dim表现型白血病细胞。结果 在23例急性B淋巴细胞白血病患儿骨髓中均可检测到CD10^ CD22^ CD45^-或dim表现型细胞,检测敏感度约为10^－4。正常人骨髓、化疗后再和髓和长期完全缓解的白血病患儿的未检测到CD10^ CD22^ CD45^-或dim表现型细胞。该法可在化疗后50d内监测到白血病细胞的变化,并且在骨髓细胞形态学确认复发之前即可检测到白血病细胞逐渐增加。结论 利用三染色－流式细胞仪检测骨髓中的CD10^ CD22^_CD45^-或dim表现型白血病细胞可以敏感地监测到急性B淋巴细胞白血病患儿微量残留病的变化。     

Ablation of PI3K blocks BCR-ABL leukemogenesis in mice, and a dual PI3K/mTOR inhibitor prevents expansion of human BCR-ABL+ leukemia cells

Some cases of pre-B cell acute lymphoblastic leukemia (pre-B-ALL) are caused by the Philadelphia (Ph) chromosome-encoded BCR-ABL oncogene, and these tend to have a poor prognosis. Inhibitors of the PI3K/AKT pathway reduce BCR-ABL-mediated transformation in vitro; however, the specific PI3K isoforms involved are poorly defined. Using a murine model of Ph+ pre-B-ALL, we found that deletion of both Pik3r1 and Pik3r2, genes encoding class IA PI3K regulatory isoforms, severely impaired transformation. BCR-ABL-dependent pre/pro-B cell lines could be established at low frequency from progenitors that lacked these genes, but the cells were smaller, proliferated more slowly, and failed to cause leukemia in vivo. These cell lines displayed nearly undetectable PI3K signaling function and were resistant to the PI3K inhibitor wortmannin. However, they maintained activation of mammalian target of rapamycin (mTOR) and were more sensitive to rapamycin. Treatment with rapamycin caused feedback activation of AKT in WT cell lines but not PI3K-deficient lines. A dual inhibitor of PI3K and mTOR, PI-103, was more effective than rapamycin at suppressing proliferation of mouse pre-B-ALL and human CD19+CD34+)Ph+ ALL leukemia cells treated with the ABL kinase inhibitor imatinib. Our findings provide mechanistic insights into PI3K dependency in oncogenic networks and provide a rationale for targeting class IA PI3K, alone or together with mTOR, in the treatment of Ph+ ALL.     

Prime-boost vaccines encoding an intracellular idiotype/GM-CSF fusion protein induce protective cell-mediated immunity in murine pre-B cell leukemia

Two vaccines against an intracellularly expressed B cell idiotype were assessed for their ability to induce protective immunity in mice against challenge with a pre-B cell leukemia. One vaccine was based on a plasmid expression vector and the other was a recombinant vaccinia virus; both vaccines expressed a polypeptide derived from the complementarity-determining regions (CDR(2)-CDR(3)) of the leukemic clone-specific immunoglobulin heavy chain (IgH), as a fusion product with mouse granulocyte-macrophage colony-stimulating factor (mGM-CSF). Mice inoculated with either vaccine showed significantly higher survival rates than controls after challenge with leukemia cells. However, protection from tumor challenge was optimal when the DNA vaccine was used for priming, followed by a booster immunization with the vaccinia virus recombinant. This vaccination protocol induced resistance not only to the first tumor challenge given shortly afterwards, but also to a second challenge given months later. Both CD4(+) and CD8(+) T cells contributed to protection in vaccinated mice. These data suggest that such a vaccine regimen might reduce the incidence of recurrence in patients with minimal residual disease after conventional therapy.     

Activation-induced cytidine deaminase acts as a mutator in BCR-ABL1-transformed acute lymphoblastic leukemia cells

The Philadelphia chromosome (Ph) encoding the oncogenic BCR-ABL1 kinase defines a subset of acute lymphoblastic leukemia (ALL) with a particularly unfavorable prognosis. ALL cells are derived from B cell precursors in most cases and typically carry rearranged immunoglobulin heavy chain (IGH) variable (V) region genes devoid of somatic mutations. Somatic hypermutation is restricted to mature germinal center B cells and depends on activation-induced cytidine deaminase (AID). Studying AID expression in 108 cases of ALL, we detected AID mRNA in 24 of 28 Ph(+) ALLs as compared with 6 of 80 Ph(-) ALLs. Forced expression of BCR-ABL1 in Ph(-) ALL cells and inhibition of the BCR-ABL1 kinase showed that aberrant expression of AID depends on BCR-ABL1 kinase activity. Consistent with aberrant AID expression in Ph(+) ALL, IGH V region genes and BCL6 were mutated in many Ph(+) but unmutated in most Ph(-) cases. In addition, AID introduced DNA single-strand breaks within the tumor suppressor gene CDKN2B in Ph(+) ALL cells, which was sensitive to BCR-ABL1 kinase inhibition and silencing of AID expression by RNA interference. These findings identify AID as a BCR-ABL1-induced mutator in Ph(+) ALL cells, which may be relevant with respect to the particularly unfavorable prognosis of this leukemia subset.     

Ph阳性急性淋巴细胞白血病的临床研究

目的研究Ph染色体阳性(Ph+)急性淋巴细胞白血病(ALL)的生物学特点与临床治疗转归。方法30例成人ALL经MIC检查确诊为Ph+B细胞ALL。经环磷酰胺、长春新碱、柔红霉素、泼尼松加或不加左旋门冬酰胺酶(CODP±L)方案诱导化疗,化疗不缓解者给予伊马替尼治疗,400～600mg/d,持续服用至完全缓解(CR)。14例缓解后行异基因造血干细胞移植(alloHSCT),16例进行巩固强化治疗。结果30例Ph+ALL患者占同期92例ALL患者的32.6%。中位年龄25.5(14～60)岁。单纯t(9;22)16例,有附加染色体异常14例;P190蛋白阳性率为68.4%;P210蛋白阳性率为31.6%;细胞免疫学标记均为B细胞表达,其中CD34细胞阳性率76.7%,髓系表达(CD13或CD33)阳性率43.3%。30例患者中WBC>30×109/L22例,其中9例WBC>100×109/L。经常规化疗,单纯Ph+ALL缓解率为68.8%,伴附加染色体异常者为28.6%(P>0.05);7例未缓解患者应用伊马替尼治疗均达CR,Ph+ALL总缓解率为73.3%。单纯Ph+ALL与伴附加染色体异常者的中位缓解期分别为9及4个月(P<0.05);中位生存期分别为9个月及7个月(P>0.05)。移植患者与持续化疗者中位缓解期分别为8个月及4.5个月(P<0.05);中位生存期为12.5及6个月(P<0.05)。结论有附加染色体异常对Ph+ALL患者的预后和疗效有一定的负性影响,伊马替尼对Ph+ALL诱导治     

CD66c在成人急性白血病细胞上的表达及意义

目的探讨CD66c及其基因CEACAM6在成人急性白血病细胞上的表达及意义.方法体外培养HL-60、K562、LCL721.221和Jurkat等急性白血病细胞,RT-PCR检测急性白血病患者骨髓细胞和白血病细胞中CEACAM6 mRNA的表达,并用多参数流式细胞术检测白血病细胞及白血病患者骨髓细胞CD66c分子的表达.同时对199例白血病患者骨髓细胞作细胞遗传学分析,并对25例CD66c阳性急性B淋巴细胞白血病（B-ALL）患者进行白血病微量残留病（MRD）分析.结果①HL-60、K562、LCL721.221和Jurkat细胞的细胞膜和细胞质CD66c均阴性.②127例急性髓系白血病（AML）患者中4例CD66c阳性（3.15%）,以M2、M4为主;79例ALL中CD66c阳性28例（35.44%）,均为B-ALL;CD66c只在common B-ALL（54例中有20例）和pre B-ALL（11例中有8例）亚型表达,8例Ph＋B-ALL患者CD66c均阳性.③MRD阳性与阴性组患者比较,6个月内复发率差异有统计学意义（维持治疗14周时MRD阳性者8例,其中6例复发;MRD阴性者17例,其中2例复发）.④CEACAM6 mRNA在CD66c阳性B-ALL细胞强表达,在HL-60细胞呈弱表达,在K562、LCL721.221和Jurkat细胞不表达.结论CD66c在ALL中阳性表达是白血病MRD检测的标志之一.CD66c抗原表达与CEACAM6 mRNA的表达高度相关.     

成人急性淋巴细胞白血病的分型探讨

目的 研究成人急性淋巴细胞白血病(ALL)生物学特征,分析WHO 2008年ALL分类的变化.方法 应用流式细胞术、R显带常规核型分析法、RT-PCR技术对初诊成人ALL患者进行免疫学、细胞遗传学、分子生物学检测.结果 ①共412例初诊成人ALL患者,男性239例,女性173例.免疫表型可分析病例410例,B系357例...     

The BCR-ABL1 kinase bypasses selection for the expression of a pre-B cell receptor in pre-B acute lymphoblastic leukemia cells

The BCR-ABL1 kinase expressed in acute lymphoblastic leukemia (ALL) drives malignant transformation of human pre-B cells. Comparing genome-wide gene expression profiles of BCR-ABL1+ pre-B ALL and normal bone marrow pre-B cells by serial analysis of gene expression, many genes involved in pre-B cell receptor signaling are silenced in the leukemia cells. Although normal pre-B cells are selected for the expression of a functional pre-B cell receptor, BCR-ABL1+ ALL cells mostly do not harbor a productively rearranged IGH allele. In these cases, we identified traces of secondary VH gene rearrangements, which may have rendered an initially productive VH region gene nonfunctional. Even BCR-ABL1+ ALL cells harboring a functional VH region gene are unresponsive to pre-B cell receptor engagement and exhibit autonomous oscillatory Ca2+ signaling activity. Conversely, leukemia subclones surviving inhibition of BCR-ABL1 by STI571 restore responsiveness to antigen receptor engagement and differentiate into immature B cells expressing immunoglobulin light chains. BCR-ABL1 kinase activity is linked to defective pre-B cell receptor signaling and the expression of a truncated isoform of the pre-B cell receptor-associated linker molecule SLP65. Also in primary leukemia cells, truncated SLP65 is expressed before but not after treatment of the patients with STI571. We conclude that inhibition of BCR-ABL1 reconstitutes selection for leukemia cells expressing a functional (pre-) B cell receptor.     

Novel membrane-bound GM-CSF vaccines for the treatment of cancer: generation and evaluation of mbGM-CSF mouse B16F10 melanoma cell vaccine

Cancer vaccines composed of tumor cells engineered to secrete granulocyte-macrophage colony-stimulating factor (GM-CSF) are currently being clinically evaluated. To enhance the immunogenicity of GM-CSF-secreting tumor cell vaccines, a novel approach expressing GM-CSF as a membrane-bound form (mbGM-CSF) on the tumor cell surface was investigated. The intent was to enhance antigen presentation by increasing interactions between the tumor cell lines in the vaccine and GM-CSF receptor positive antigen presenting cells (APC), notably the patient's Langerhans cells residing within the intradermal injection site. B16.F10 cells engineered to express either membrane-bound or secreted GM-CSF were compared in the B16.F10 mouse melanoma model. We observed that mbGM-CSF on the tumor cell surface retarded growth and induced protective immunity to subsequent wild-type tumor challenge more effectively than tumor cells secreting GM-CSF. Vaccination with irradiated mbGM-CSF B16.F10 also provided strong protection from wild-type tumor challenge, improved therapeutic effects against established tumors, and retarded lung metastases. These results demonstrate that mbGM-CSF B16.F10 cells can induce strong systemic immunity that protects against and therapeutically treats B16.F10 melanoma more effectively than analogous vaccines containing only secreted GM-CSF. These data warrant further development and clinical testing of mbGM-CSF tumor cell vaccines.     

Bi-phenotypic leukemia and hybrid leukemia]

Phenotypes of leukemic cells can be determined through dual staining with pairs of FITC-labeled and PE-labeled monoclonal antibodies using a laser flow cytometer. Hybrid acute leukemia (HAL) was diagnosed when leukemic cells expressed 2 or more lymphoid markers and at least one myeloid maker simultaneously. Based on this criteria, forty out of 111 cases with untreated acute leukemia were diagnosed as HAL, 16 of 41 (39%) patients with acute lymphoblastic leukemia and 15 of 70 (21%) patients with acute non-lymphocytic leukemia were diagnosed as having HAL. We classified these HAL cells into 4 types by the following items. Type I; leukemic cells expressed only CD33 and 2 or more B-cell antigens, type II; only CD33 and 2 or more T-cell antigens, type III; CD13 and/or CD33 and 2 or more B-cell antigens, and type IV; CD13 and/or CD33 and 2 or more T-cell antigens. There were 7 type I cases and 16 type III cases. The leukemic cells of these two types were thought to be ALL cells expressing one or several myeloid lineage-associated antigens. There were 4 type II cases and 10 type IV cases. Type II and IV were regarded as lymphoid-lineage associated antigens positive AMLs. At least in adults, the expression of myeloid-associated antigens of ALL cells seems to identify a high risk group of ALL patients with a poorer response to standard ALL therapy.     

A therapeutic cancer vaccine delivers antigens and adjuvants to lymphoid tissues using genetically modified T cells

Therapeutic vaccines that augment T cell responses to tumor antigens have been limited by poor potency in clinical trials. In contrast, the transfer of T cells modified with foreign transgenes frequently induces potent endogenous T cell responses to epitopes in the transgene product, and these responses are undesirable, because they lead to rejection of the transferred T cells. We sought to harness gene-modified T cells as a vaccine platform and developed cancer vaccines composed of autologous T cells modified with tumor antigens and additional adjuvant signals (Tvax). T cells expressing model antigens and a broad range of tumor neoantigens induced robust and durable T cell responses through cross-presentation of antigens by host DCs. Providing Tvax with signals such as CD80, CD137L, IFN-β, IL-12, GM-CSF, and FLT3L enhanced T cell priming. Coexpression of IL-12 and GM-CSF induced the strongest CD4⁺ and CD8⁺ T cell responses through complimentary effects on the recruitment and activation of DCs, mediated by autocrine IL-12 receptor signaling in the Tvax. Therapeutic vaccination with Tvax and adjuvants showed antitumor activity in subcutaneous and metastatic preclinical mouse models. Human T cells modified with neoantigens readily activated specific T cells derived from patients, providing a path for clinical translation of this therapeutic platform in cancer.