膀胱肿瘤抗原致敏的树突状细胞诱导T淋巴细胞抗肿瘤效应的研究

目的：研究经膀胱肿瘤抗原致敏后的树突状细胞（Dc）对T淋巴细胞的激活、增殖作用及对T24膀胱肿瘤细胞的抑癌效应。方法：分离健康供血者外周血单个核细胞及T淋巴细胞，联合应用粒／巨噬细胞集落刺激因子（GM—CSF）及白介素-4（IL-4）从单个核细胞中培养出Dc，以人膀胱癌细胞系T24肿瘤细胞裂解物刺激Dc，检测经膀胱肿瘤抗原致敏后的DC对T淋巴细胞的细胞增殖动力学影响并用M1rr显色法测定致敏Dc诱导的T淋巴细胞对T24膀胱肿瘤细胞体外的抗肿瘤效应。结果：膀胱癌细胞裂解物致敏的Dc可诱导T淋巴细胞强烈的增殖反应，与对照组比较具有显著性差异（P〈0．01）；增殖后的T淋巴细胞对T24膀胱肿瘤细胞有明显的细胞毒作用。结论：经膀胱肿瘤抗原致敏的Dc能诱导产生显著的T淋巴细胞增殖，在体外有明显的抑癌效应。     

Tumour‐associated glycan modifications of antigen enhance MGL2 dependent uptake and MHC class I restricted CD8 T cell responses

We recently showed that MGL2 specifically binds tumour‐associated glycan N‐acetylgalactosamine (GalNAc). We here demonstrate that modification of an antigen with tumour‐associated glycan GalNAc, targets antigen specifically to the MGL2 on bone marrow derived (BM)‐DCs and splenic DCs. Glycan‐modification of antigen with GalNAc that mimics tumour‐associated glycosylation, promoted antigen internalisation in DCs and presentation to CD4 T cells, as well as differentiation of IFN‐γ producing CD4 T cells. Furthermore, GalNAc modified antigen enhanced cross‐presentation of both BM‐DCs and primary splenic DCs resulting in enhanced antigen specific CD8 T cell responses. Using MyD88‐TRIFF^?/? BM‐DCs we demonstrate that the enhanced cross‐presentation of the GalNAc modified antigen is TLR independent. Our data strongly suggest that tumour‐associated GalNAc modification of antigen targets MGL on DCs and greatly enhances both MHC class II and class I presentation in a TLR independent manner.     

Improved vaccine efficacy of tumor exosome compared to tumor lysate loaded dendritic cells in mice

Leukemia immunotherapy frequently does not meet expectation, one of the handicaps being tumor exosome (TEX)‐promoted immunosuppression. We here asked, using the mouse myeloid leukemia WEHI3B and the renal cell carcinoma line RENCA, whether dendritic cell (DC) vaccination suffices to counterregulate TEX‐induced immunosuppression and whether TEX could serve as tumor antigen for DC‐loading. DC‐vaccination significantly prolonged the survival time of WEHI3B‐bearing mice, TEX‐loaded DC (DC‐TEX) being superior to lysate‐loaded DC (DC‐lys), even an excess of TEX not interfering with immune response induction. The superior response to DC‐TEX was accompanied by an increase in WEHI3B‐specific CD4⁺ T cells, evaluated by trogocytosis and proliferation. Similar findings accounted for DC loaded with RENCA TEX. TEX was efficiently taken‐up by DC and TEX uptake supported CD11c, MHCII and IL12 upregulation in DC. Importantly, TEX was partly recruited into the MHCII‐loading compartment such that “TEX” presentation time and recovery in T cells significantly exceeded that of tumor‐lysate. Thus, TEX did not drive DC into a suppressive phenotype and were a superior antigen due to higher efficacy of TEX‐presentation that is supported by prolonged persistence, preferential processing in the MHCII‐loading compartment and pronounced trogocytosis by T helper cells. TEX is present in tumor patients' sera. TEX, recovered and enriched from patients' sera, might well provide an optimized, individual‐specific antigen source for DC‐loading and vaccination.     

Human natural killer cells promote cross‐presentation of tumor cell‐derived antigens by dendritic cells

Dendritic cells (DCs) cross‐present antigen (Ag) to initiate T‐cell immunity against most infections and tumors. Natural killer (NK) cells are innate cytolytic lymphocytes that have emerged as key modulators of multiple DC functions. Here, we show that human NK cells promote cross‐presentation of tumor cell‐derived Ag by DC leading to Ag‐specific CD8⁺ T‐cell activation. Surprisingly, cytotoxic function of NK cells was not required. Instead, we highlight a critical and nonredundant role for IFN‐γ and TNF‐α production by NK cells to enhance cross‐presentation by DC using two different Ag models. Importantly, we observed that NK cells promote cell‐associated Ag cross‐presentation selectively by monocytes‐derived DC (Mo‐DC) and CD34‐derived CD11b^negCD141^high DC subsets but not by myeloid CD11b⁺ DC. Moreover, we demonstrate that triggering NK cell activation by monoclonal antibodies (mAbs)‐coated tumor cells leads to efficient DC cross‐presentation, supporting the concept that NK cells can contribute to therapeutic mAbs efficiency by inducing downstream adaptive immunity. Taken together, our findings point toward a novel role of human NK cells bridging innate and adaptive immunity through selective induction of cell‐associated Ag cross‐presentation by CD141^high DC, a process that could be exploited to better harness Ag‐specific cellular immunity in immunotherapy.     

Apoptotic body-loaded dendritic cells efficiently cross-prime cytotoxic T lymphocytes specific for NA17-A antigen but not for Melan-A/MART-1 antigen

DCs hold promise for cancer immunotherapy due to their functional ambivalence: iDCs internalize antigens, then mDCs trigger naive T-cell activation. However, no consensus has been reached concerning the optimal mode of antigen acquisition for efficient cross-priming of TAA-specific CTLs, and this remains a field of investigation. Here, we used highly purified apobodies derived from an HLA-A*0201-negative melanoma line as a source of tumor antigens for HLA-A*0201 DCs. We compared in vitro mDCs loaded with apobodies to DCs loaded with antigenic peptides, NA17-A(1-9) and Melan-A/MART-1(26-35) A27L analogue, for their capacity to stimulate melanoma antigen-specific T cells from autologous PBLs. Apobody phagocytosis did not induce spontaneous DC maturation, but phagocytic DCs were still responsive to maturation signals, resulting in a functional ability to activate antigen-specific lymphocytes. NA17-A-specific T lymphocytes were activated by both types of stimulation, whereas only peptide-pulsed DCs stimulated the growth of Melan-A/MART-1-specific lymphocytes. We also observed a lack of staining of melanoma-derived apobodies with a Melan-A-specific MAb, suggesting protein alteration during apoptosis induction. After HLA-A*0201/NA17-A multimer sorting, antigen-specific lymphocytes induced by mature DCs loaded with either peptide or apobodies displayed similar functional capacity against peptide-pulsed T2 cells and melanoma cells. Therefore, apobody-loaded DCs can achieve T-cell priming similar to that induced by peptide-pulsed DCs, provided that the apoptotic process allows the preservation of antigen expression.     

膀胱肿瘤抗原致敏的树突状细胞诱导 T 淋巴细胞抗肿瘤效应的研究

目的：研究经膀胱肿瘤抗原致敏后的树突状细胞（Dc）对T淋巴细胞的激活、增殖作用及对T24膀胱肿瘤细胞的抑癌效应。方法：分离健康供血者外周血单个核细胞及T淋巴细胞，联合应用粒／巨噬细胞集落刺激因子（GM—CSF）及白介素-4（IL-4）从单个核细胞中培养出Dc，以人膀胱癌细胞系T24肿瘤细胞裂解物刺激Dc，检测经膀胱肿瘤抗原致敏后的DC对T淋巴细胞的细胞增殖动力学影响并用M1rr显色法测定致敏Dc诱导的T淋巴细胞对T24膀胱肿瘤细胞体外的抗肿瘤效应。结果：膀胱癌细胞裂解物致敏的Dc可诱导T淋巴细胞强烈的增殖反应，与对照组比较具有显著性差异（P〈0．01）；增殖后的T淋巴细胞对T24膀胱肿瘤细胞有明显的细胞毒作用。结论：经膀胱肿瘤抗原致敏的Dc能诱导产生显著的T淋巴细胞增殖，在体外有明显的抑癌效应。     

胃癌术后化疗联合自体肿瘤细胞抗原致敏DC CIK细胞治疗的疗效

目的:探讨进展期胃癌根治术后化疗联合自体肿瘤细胞抗原致敏树突状细胞-细胞因子诱导的杀伤(autologous tumor antigen load dendritic cells-cytokin-induced killer,Ag-DC-CIK)细胞治疗的疗效和安全性.方法:收集2013年1月至2014年3月于荆州市中心医院胃肠外科诊断为进展期(Ⅱ期和Ⅲ期)胃癌的60例患者,均接受胃癌D2根治术,术后按照随机数字表法分为两组,单纯化疗组采用FOLFOX化疗方案,给予6个周期化疗;联合治疗组除给予上述化疗外,同时给予Ag-DC-CIK细胞进行治疗.随访期2年,观察两组患者2年OS和PFS、外周血T细胞亚群免疫学指标(CD3+、CD4+、CD8+、CD3+CD56+)、生活质量评分、化疗不良反应分级.结果:联合治疗组患者2年OS及PFS较单纯化疗组明显提高(均P＜0.05).联合治疗组治疗前后外周血T细胞亚群水平无明显变化(P＞0.05),而单纯化疗组治疗后外周血T细胞亚群水平明显降低(P＜0.05),且明显低于联合治疗组(P＜0.05);联合治疗组的综合生活质量评分明显高于单纯化疗组[(7.25±1.56) vs(5.54±1.27)分,P＜0.05].联合治疗组不良反应发生率明显低于单纯化疗组(10.0％ vs 20.0％,P＜0.05).结论:Ag-DC-CIK细胞治疗联合化疗能显著提高胃癌术后患者的2年OS及PFS,保护机体的免疫功能,减少化疗的不良反应,改善其生活质量.     

The effects of STI571 on antigen presentation of dendritic cells generated from patients with chronic myelogenous leukemia

Chronic myelogenous leukemia is caused by the acquisition of the reciprocal (9;22)(q34;q11) chromosomal translocation in hematopoietic stem cells. The fusion protein showed higher and aberrant tyrosine kinase activity. The inhibition of the tyrosine kinase activity of the protein represents a specific therapeutic strategy for bcr/abl-expressing leukemias. STI571 is a compound of the 2-phenylaminopyrimidine class that selectively inhibits the tyrosine kinase activity of the Abl protein tyrosine kinase. In this study, we evaluated the effects of STI571 on antigen presentation of dendritic cells generated from the patients with CML. The data showed that by the addition of STI571 the dendritic cells derived from CML clone showed an increased expression of CD1a, CD83, CD80 and CD86 by flow cytometry analysis and showed more intense abilities of allogeneic antigen presentation by mixed leukocyte culture, compared with the control cells without STI571. Our results suggested that STI571 not only has a direct cytotoxic effect on bcr-abl gene rearranged cells but also an indirect effect associated with increased anti-leukemic immunological function due to an intensified antigen presentation.     

Enhancement of myeloma development mediated though myeloma cell-Th2 cell interactions after microbial antigen presentation by myeloma cells and DCs

Microbial agents are regarded as a potential cause of tumors, but their direct effects on tumors, such as myeloma, are not well studied. Our studies demonstrated that expression of HLA-DR and CD40 on the myeloma cell membrane surface is upregulated by interferon-γ and/or microbial antigens (Ags). Unlike prior studies, our study showed that Th2 cells cannot promote myeloma growth directly. However, Bacillus Calmette-Guerin Vaccine (BCGV)-specific Th2 cells stimulated by BCGV-loaded dendritic cells (DCs) promoted myeloma clonogenicity directly when the myeloma cells expressed major histocompatibility complex Class-II molecules (MHC-II) and took up BCGV Ag. B-cell lymphoma 6 (Bcl-6) protein expression and the proportion of HLA-DR(+) or CD40(+) cells were higher in colonies of Th2 cell-stimulated myeloma cells. Furthermore, anti-HLA-DR or neutralizing CD40 antibody could prevent this increase in Bcl-6 expression and colony number. These results indicate that microbes and microbial Ag-specific Th2 cells may directly impact the biology of myeloma and contribute to tumor progression. Activation may be limited to MHC-II(+) myeloma cells that retain B cell and stem cell characteristics. Taken together, our data suggest that factors involved in microbial Ag presentation, such as DCs, Th2 cells and so on, are potential targets for myeloma therapeutic intervention.     

Influence of drug-induced apoptotic death on processing and presentation of tumor antigens by dendritic cells

Here we have studied the effects of apoptotic cell death induced by chemotherapic agents on tumor phagocytosis by dendritic cells (DC) and presentation of the relevant antigen to T lymphocytes. Annexin-V-FITC (Ann-V) and propidium iodide (PI) staining was used to assess early apoptotic (Ann-V(+)/PI(-)) vs. late apoptotic/secondary necrotic (Ann-V(+)/PI(+)) death after a 24 hr observation of untreated and drug-treated gastric carcinoma cells. After treatments, the HLA-A*0201(+) tumor cell line KATO III was exposed for 24 hr to allogeneic, HLA-related GM-CSF, IL-4-driven immature (i) DC. Tumor-loaded iDC were tested for IL-12 release in an ELISA assay, incubated with the DC-maturating factor TNF-alpha and used as stimulators for autologous T lymphocytes. Generation of antitumor T response against KATO cells was evaluated in an anti-MHC class I MAb-blocked Interferon-gamma ELISPOT assay. After treatment with Cis-platin (cis), all dying cells were in early apoptosis, whereas secondary necrosis was the prevalent death pattern observed after epirubicin (epi) and doxorubicin (doxo). Doxo and epi increased tumor expression of heat shock protein (hsp) 70 and uptake of tumor cell components by DC, whereas cis treatment had no effect on hsp70 and was associated with poor tumor uptake by DC. Significant upmodulation of IL-12 was observed by DC that had taken up the doxo- and epi-treated tumors (p< 0.005 and p< 0.01, respectively). Increased IFN-gamma release was also observed after stimulation of T lymphocytes with DC loaded with doxo- and epi-treated (p< 0.02 and p< 0.005, respectively) but not with cis-treated DC. These data show that the products of early apoptosis cannot efficiently cross-activate MHC class I-restricted anti-tumor lymphocytes even in the presence of DC maturating factors, whereas secondary necrosis is associated with robust T cell response.     

IL-18基因增强肿瘤抗原致敏DC诱导的CTL特异性杀伤肝癌细胞

目的:探讨腺病毒介导的白细胞介素18(IL18）基因转染能否使肿瘤抗原冲击的树突状细胞(dentritic cell,DC) 在体外诱导出更强的抗肝癌免疫反应。方法：携IL18 的重组腺病毒载体感染经肝癌细胞株HepG2冻融抗原致敏的DC(AdIL18HepG2/DC), FACS分析AdIL18HepG2/DC表面分子的表达, ELISA法检测IL18的分泌水平, 3HTdR掺入法检测T淋巴细胞增殖能力, MTT法检测细胞毒性T 淋巴细胞杀伤效应。结果： AdIL18HepG2/DC较未转染DC能高水平地表达CD1a、CD11c、CD80、CD86以及HLADR;较未经IL18转染的DC分泌较高水平的IL18。AdIL18HepG2/DC 能非常有效地刺激自体T 细胞增殖(CPM 值为228 018±1 079),其刺激强度显著强于AdIL18DC、HepG2/DC、AdlzcZ/DC及DC（均P＜0.05）。当靶细胞为HepG2时,AdIL18HepG2/DC诱导的CTL杀伤活性显著高于其他各组（均P＜0.05）,并且其杀伤能力与效应细胞数量成正比。结论： IL18 基因转染且肝癌抗原致敏的DC可以显著增强DC的特异性抗肝癌效应。     

Blood monocytes sample MelanA/MART1 antigen for long‐lasting cross‐presentation to CD8+ T cells after differentiation into dendritic cells

Human blood monocytes are very potent to take up antigens. Like macrophages in tissue, they efficiently degrade exogenous protein and are less efficient than dendritic cells (DCs) at cross‐presenting antigens to CD8⁺ T cells. Although it is generally accepted that DCs take up tissue antigens and then migrate to lymph nodes to prime T cells, the mechanisms of presentation of antigens taken up by monocytes are poorly documented so far. In the present work, we show that monocytes loaded in vitro with MelanA long peptides retain the capacity to stimulate antigen‐specific CD8⁺ T cell clones after 5 days of differentiation into monocytes‐derived dendritic cells (MoDCs). Tagged‐long peptides can be visualized in electron‐dense endocytic compartments distinct from lysosomes, suggesting that antigens can be protected from degradation for extended periods of time. To address the pathophysiological relevance of these findings, we screened blood monocytes from 18 metastatic melanoma patients and found that CD14⁺ monocytes from two patients effectively activate a MelanA‐specific CD8 T cell clone after in vitro differentiation into MoDCs. This in vivo sampling of tumor antigen by circulating monocytes might alter the tumor‐specific immune response and should be taken into account for cancer immunotherapy.     

Heat shock protein 90 targets a chaperoned peptide to the static early endosome for efficient cross‐presentation by human dendritic cells

The presentation of an exogenous antigen in a major histocompatibility complex class‐I‐ restricted fashion to CD8⁺ T cells is called cross‐presentation. Heat shock proteins (HSPs) such as Hsp70, gp96, and Hsp90 have been shown to elicit efficient CTL responses by cross‐presentation through an as‐yet entirely unknown mechanism. Hsp90 is the most abundant cytosolic HSP and is known to act as a molecular chaperone. We have shown that a tumor antigen peptide complexed with Hsp90 could be cross‐presented by dendritic cells (DCs) through an endosomal pathway in a murine system. However, it has not been determined whether human DCs also cross‐present an Hsp90–peptide complex and induce peptide‐specific CTLs. In this study, we found that an Hsp90–cancer antigen peptide complex was efficiently cross‐presented by human monocyte‐derived DCs and induced peptide‐specific CTLs. Furthermore, we observed that the internalized Hsp90–peptide complex was strictly sorted to the Rab5⁺, EEA1⁺ static early endosome and the Hsp90‐chaperoned peptide was processed and bound to MHC class I molecules through an endosome‐recycling pathway. Our data indicate that targeting of the antigen to a “static” early endosome by Hsp90 is essential for efficient cross‐presentation.     

Circulation and homing of melanoma-reactive T cells to both cutaneous and visceral metastases after vaccination with monocyte-derived dendritic cells.

Anticancer immune therapies aim at the induction of tumor-specific T cells, which ultimately should kill tumor cells. The effector cells should, therefore, not only exert cytotoxic activity but also home to and infiltrate the tumor site. Hence, monitoring of immune modulating therapies should not be restricted to the circulating pool of peripheral blood mononuclear cells (PBMC) but also include tumor-infiltrating lymphocytes (TIL), as well as the correlation of these findings to the clinical course. We report here on the longitudinal immunologic workup of a melanoma patient who developed remarkably potent ex vivo detectable antimelanoma cytotoxic T-cell (CTL) responses after vaccinations with autologous peptide-pulsed dendritic cells. Such potent CTL responses to multiple tumor antigens have, to the best of our knowledge, not been described previously in melanoma patients, neither spontaneously nor after any therapy. This patient first experienced a transient response to therapy but finally succumbed to disease progression and died. Progression was associated with the decline of the numbers of tumor-reactive T cells in circulation and at skin metastases in addition to the loss of MHC class I antigens. The immunologic analysis revealed that fully functional tumor-specific T cells were present in the peripheral blood of this patient during the phase of a relatively stable disease, and in situ tetramer staining demonstrated that these cells were also accumulated at cutaneous and visceral tumor sites. Furthermore, comparative clonotype mapping of PBMC and TIL depicted an overlapping TCR repertoire usage among these 2 compartments. Since strong CTL responses as observed in this patient are the goal of cancer vaccination but are so far only rarely observed, the thorough analysis of patients exhibiting either exceptional clinical and/or immunologic responses appears critical to understanding how vaccine therapies work and can be further improved.     

Recombinant E. coli efficiently delivers antigen and maturation signals to human dendritic cells: presentation of MART1 to CD8+ T cells

The generation of tumour-specific cytotoxic T-lymphocyte (CTL) responses is the primary focus in the design of immunotherapeutic cancer vaccines. We have recently demonstrated generation of ovalbumin (OVA)-specific CTLs and tumour-protection in a murine tumour model using vaccination with dendritic cells (DCs) pulsed with E. coli expressing listeriolysin O (LLO) and OVA as a model antigen. In this system paraformaldehyde fixation of E. coli/LLO provided an additional safety feature without compromising vaccine efficacy. We therefore reasoned that paraformaldehyde-fixed recombinant E. coli expressing LLO would be an efficient vehicle for the delivery of human tumour antigens to human DCs. In the present study, we demonstrate that fixed E. coli expressing LLO are taken up efficiently by human monocyte-derived DCs (MoDCs) with minimal toxicity. As a consequence of the interaction with bacteria, human DCs undergo marked phenotypic and functional maturation. Furthermore, we show that fixed E. coli/LLO expressing the well-characterised human melanoma antigen, MART1, efficiently deliver the HLA-A2-restricted MART1(27-35) epitope for processing and presentation on human MoDCs, suggesting the potential of this system as a novel strategy for human tumour immunotherapy.     

WT1致敏树突状细胞激活CTLs对HL60细胞作用的研究

目的研究分别负载WT1多肽抗原及HL60细胞冻融抗原的树突状细胞(DCs)产生的特异性细胞毒性T淋巴细胞(CTLs)对HL60细胞的杀伤效应。方法联合应用rhGM-CSF、rhIL-4、rhTNF-α及rh-sCD40L等细胞因子,诱导扩增自健康人外周血获取的单核细胞,培养出DCs,分别用WT1多肽抗原及冻融抗原冲击致敏,激活淋巴细胞。实验分4组WT1多肽致敏DCs为实验组A,HL60细胞冻融抗原致敏DCs为实验组B,未致敏DCs组为对照组A,单核细胞组为对照组B,LDH释放法检测CTLs对HL60细胞的杀伤作用。结果培养出具有典型特征的DCs,表达CD40达96%,CD80达77%,CD1α达69%,CD86达97%,体外能诱导强烈的同种异体混合淋巴结胞增殖反应。在效靶比为20∶1时,WT1多肽致敏DCs组时HL60细胞杀伤率为89.1%,冻融抗原负载DCs组为90.6%,未致敏DCs组为32.8%,单核细胞组为26.1%。以下多肽或冻融抗原负载DCs与对照组相比显示更强的杀伤效应,P<0.01。结论WT1多肽抗原及HL60细胞冻融抗原冲击致敏DCs均能有效诱导T细胞抗白血病作用,为临床研制DCs疫苗提供实验依据。     

Generation of antigen-specific cytotoxic T lymphocytes using a leukemic plasmacytoid dendritic cell line as antigen presenting cells

Establishment of a leukemia plasmacytoid dendritic cell line (PMDC05) and intra-lineage transformation from pDCs to mDCs in PMDC05 has been reported. In this paper, we show the applicability of PMDC05 for cellular immunotherapy. By stimulation with LPS, PMDC05 showed enhancement in expression of antigen presentation-associated surface molecules and production of cytokines (IL-12p70 and TNF-α). The antigen presenting ability was markedly increased in PMDC05 stimulated with LPS. By co-culturing of CD8⁺ T cells with LPS-stimulated and WT1/CMVpp65 peptide-pulsed PMDC05, WT1/CMVpp65 tetramer⁺ cytotoxic T lymphocytes were efficiently generated. These findings reveal the applicability of PMDC05 in cellular immunotherapy for tumor and severe viral infections.     

Unique presentation of blastic plasmacytoid dendritic cell neoplasm: a single‐center experience and literature review

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and highly aggressive hematological malignancy derived from precursors of plasmacytoid dendritic cells. Very few cases of BPDCN have been described with lack of skin manifestations at the time of diagnosis. Here we report two rare non‐cutaneous presentations of BPDCN without obvious skin lesions at our institution and also the literature review. Our first patient had a unique presentation of BPDCN confined to the sinonasal region with central nervous system involvement. The second patient we report is also atypical with regard to widespread disease that uncharacteristically spared the skin and bone marrow. BPDCN is a rare hematological malignancy involving immature plasmacytoid dendritic cells. It poses a diagnostic challenge requiring multidisciplinary approach to manage this disease. It is important to identify effective therapies for both cutaneous and non‐cutaneous presentations of BPDCN, since most cases are uniformly fatal with conventional chemotherapy alone. High‐dose induction therapy based on acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL) regimens, to achieve complete remission followed by allo‐hematopoietic stem cell transplantation from related or unrelated donors is recommended to improve long‐term survival in these patients. Larger scale studies are warranted to understand the pathophysiology of the disease and the important prognostic indicators for optimal management. Copyright © 2014 John Wiley & Sons, Ltd.     

热休克肿瘤细胞抗原负载的树突状细胞对结肠癌小鼠的治疗作用

背景与目的:目前通过树突状细胞诱导机体抗肿瘤免疫已经成为肿瘤免疫治疗的一种重要途径,热休克处理肿瘤细胞可提高肿瘤细胞抗原负载的树突状细胞分化成熟,增强其体内抗肿瘤作用.本实验研究热休克肿瘤细胞抗原负载的骨髓来源的树突状细胞(dendritic cell,DC)对结肠癌小鼠的治疗作用.方法:20只小鼠随分为4组,将小鼠结肠癌细胞CT26热休克处理后超声破膜,以其细胞裂解液负载BALB/c小鼠骨髓来源的DC,观察DC诱导肿瘤特异性细胞毒性T淋巴细胞(cytotoxic T lymphocyte,CTL)杀伤活性;并将DC接种于荷瘤小鼠皮下,观察其对肿瘤生长的抑制作用及对荷瘤小鼠生存期的影响.结果:与冻融抗原-DC组、DC组、PBS组相比,热休克抗原-DC诱导的CTL对CT26肿瘤细胞具有显著的杀伤作用,相同效靶比(P=0.00)下其肿瘤特异性细胞毒活性强于前者{(0.99±0.19)g vs.[(1.27±0.28)g、(2.19±0.35)g、(2.14±0.27)g],P均=0.00};用其进行免疫后对小鼠肿瘤的生长具有显著的抑制作用[(128±18)mm3 vs. (313±52)mm3,P=0.04],并能显著延长荷瘤小鼠的生存时间{(57±7)d vs. [(40±3)d、(25±3)d、(24±3)d],P均=0.00}.结论:热休克肿瘤细胞抗原负载的树突状细胞对结肠癌小鼠具有显著的治疗效果.