Cognate interactions between memory T cells and tumor antigen-presenting dendritic cells from bone marrow of breast cancer patients: bidirectional cell stimulation,survival and antitumor activity in vivo

Dendritic cells (DC) and T cells were generated from Ficoll separated bone marrow (BM) mononuclear cells of primary operated breast cancer patients according to new cell culture protocols. BM-DC were capable of functioning as professional antigen-presenting cells (APCs) and of inducing autologous antigen-specific memory T-cell responses to either tetanus toxoid recall antigen or to breast cancer antigens. Treatment with lipopolysaccharide (LPS) resulted in phenotypic and functional maturation of BM-DC. When BM-DC, pulsed with breast cancer-associated tumor antigens, were cocultured with autologous patient-derived BM-T cells to allow for cognate breast cancer antigen recognition and stimulation, apoptosis of T cells-which occurred in noncognate coculture systems-was inhibited. Furthermore, in cocultures allowing for antigen-specific cognate interactions, the expression on BM-DC of CD83, MHC class II, CD40 and CD86 molecules was upregulated and the cytokines IL-12 and IFN-alpha were produced in significantly elevated amounts. Adoptive transfer of breast cancer-reactive memory T cells together with APCs into human breast cancer-bearing NOD/SCID mice caused a regression of the tumor and prolonged survival of the animals. This was not the case when such animals had been treated by transfer of reactivated BM T cells without BM-DCs. Our findings suggest that cognate interactions between cancer patient-derived memory BM-T cells and tumor antigen-presenting BM-DCs are important for reciprocal cell stimulation, survival and therapeutic activity.     

DC活化淋巴细胞对自体乳腺癌细胞的杀伤作用

 目的探讨负载自体抗原DC诱导的CTLs对自体乳腺癌细胞的杀伤作用。方法以负载自体癌细胞抗原的DCs体外诱导CTLs,用ELISA法检测IFN-γ和IL-12的表达水平,用LDH法检测CTL对自体癌细胞的杀伤作用。结果负载自体抗原DC组IFN-γ和IL-12的浓度高于未致敏DC组、抗原组及单核细胞对照组(P<0.05),且负载抗原DC组所刺激的CTLs的杀伤作用也强于未致敏DC组、抗原组及单核细胞组(P<0.01)及对照的MCF-7组和HT-29组(P<0.01)。结论肿瘤裂解物致敏DC可持续刺激特异性CTLs从而可在体外杀伤乳腺癌患者的自体肿瘤细胞,说明肿瘤抗原致敏的DC疫苗对于治疗残留的和(或)对化疗耐药乳腺癌可能是适合的,因而有可能成为标准的补救措施。     

Dendritic cells fused with allogeneic breast cancer cell line induce tumor antigen-specific CTL responses against autologous breast cancer cells

Dendritic cell (DC)/tumor cell fusion vaccine has been revealed as a promising tool for the antitumor immunotherapy. Previous research has shown that fusion hybrids of human DCs and autologous tumor cells can induce cytotoxic T lymphocyte (CTL) responses against autologous tumor cells in animal models and human clinical trials. However, a major restriction factor for the clinical use is the difficulty for preparation of sufficient amount of autologous tumor cells especially for the patients with metastasis cancer whose primary tumor lesion is not clear or has been resected. In this study, allogeneic breast cancer cell line MCF-7 cells were electrofused to autologous DCs from patient with breast cancer as a strategy to deliver shared breast cancer antigens to DCs. Fusion cells generated by autologous DCs and allogeneic MCF-7 were able to induce autologous T lymphocytes proliferation, high levels of IFN-gamma production and CTL responses. CTLs induced by DCs/allogeneic MCF-7 fusion cells were able to kill autologous breast cancer cells in an antigen specific and HLA restriction manner. Our study may provide the experiment basis for the use of allogeneic breast cancer cell line in the DC/tumor cell fusion cell vaccination strategy.     

Newcastle disease virus infection induces B7-1/B7-2-independent T-cell costimulatory activity in human melanoma cells

Viral oncolysates of Newcastle disease virus (NDV) have been widely used for the treatment of malignant melanoma. Apparently, this nononcogenic and apathogenic paramyxovirus can alter the immunogenicity of tumor cells. To determine the influence of NDV infection on a tumor-specific T-cell response on a functional level, we used autologous primary melanoma cells infected with the NDV-strain Ulster. Therefore, melanoma cells and tumor-infiltrating lymphocytes were prepared from a freshly resected tumor, and tumor-infiltrating lymphocytes were subjected to limited dilution cloning. Proliferation assays of the T-helper cell clone sTS3 (CD4+) showed that the T-cell clone was rendered nonreactive against its autologous major histocompatibility complex II+, B7-1/B7-2- melanoma SMS, even remaining unresponsive to subsequent stimulation by interleukin-2. NDV infection of the SMS melanoma cell line not only completely restored the proliferative response of sTS3 to SMS, comparable with stimulation by cross-linking of anti-CD3/anti-CD28 monoclonal antibodies, but also inhibited the induction of anergy. Electrophoretic mobility shift assays of sTS3 cell lysates revealed the induction of the CD28-responsive complex by coincubation with NDV-infected melanoma cells. Because the induction of this complex of nuclear proteins shows specificity for the activation of the CD28 pathway but functional B7-1/B7-2 expression was not detectable on SMS melanoma cells at any timepoint, we propose the induction of a costimulatory factor different from B7 by NDV viral proteins.     

Human T cell responses to HPV 16 E2 generated with monocyte-derived dendritic cells.

Persistent infection with human papillomavirus (HPV) type 16 has been implicated in the etiology of cervical cancer. The E2 protein is required early in viral infection and therefore may serve as a useful immune target for a vaccine aimed at prevention or therapy of premalignant lesions. Dendritic cells (DC) prepared from monocytes and pulsed with bacterially produced HPV 16 E2 C-terminus protein were used to stimulate autologous T cells over several rounds of stimulation. T cells were tested for gamma-interferon release by ELISPOT and for cytotoxic activity by (51)chromium release assays. To generate E2-expressing target cells for cytotoxicity assays, we constructed a recombinant vaccinia virus encoding HPV 16 E2, which was used to infect autologous Epstein-Barr virus-transformed lymphoblastoid cell lines (LCL). The results show that DC pulsed with E2 C-terminus protein induce gamma-interferon-releasing T cells as demonstrated by ELISPOT. Furthermore, we demonstrate E2-specific lysis of vaccinia-E2 infected autologous LCL by CD8+ cytotoxic T lymphocytes (CTL). E2-specific CTL did not lyse untreated autologous LCL or LCL infected with wild-type vaccinia and showed low levels of cytotoxicity against natural killer cell-sensitive K562 cells. In addition, T cells stimulated with DC in the absence of E2 failed to demonstrate lysis of vaccinia-E2-labeled targets. Phenotypically, CTL populations were CD3+/CD8+. These results will facilitate the study of naturally occurring T-cell responses to HPV E2 in patients with cervical intraepithelial neoplasia and the development of immunotherapeutic strategies designed to treat this and other HPV-associated diseases.     

来源于人膀胱癌细胞株EJ的HSP70负载的DC所激发的特异性CTL细胞的体外应答效应

Objective: To investigate whether human dendritic cells (DC) derived from peripheral blood mononuclear cells (PBMC), which were pulsed by heat shock protein 70 (HSP70) isolated from human bladder tumor cell lines of EJ, were able to induce peptide specific cytotoxic T-lymphocytes (CTL) response in vitro and give the experimental foundation for the future clinical trials of immunotherapy in bladder tumor. Methods: The EJ-derived HSP70 co-cultured with DC from the healthy volunteers' PBMC, along with the crude lysate (the supernatant before HSP70 purification) from EJ cells were used as the experimental groups and DC not pulsed by any tumor cells antigen were the blank control. The autologous T-lymphocytes were added into the above various DC groups, and after incubation, the stimulation indexes (SI) and interferon-γ (IFN-γ) were detected to evaluate the immune activities of various DC groups. The killing effects of CTL to target cells, EJ and Hela cells, were determined with 51Cr releasing test. Results: Both DC/HSP70 and DC/the crude lysate could effectively activate CTL in vitro and kill target cells EJ. The killing effect of DC/HSP70 to EJ was much stronger than DC/the crude lysate (the supernatant before HSP70 purification) (P < 0.05). DC without any tumor cell antigens had a lower killing power to EJ. Meanwhile, DC/ HSP70 had little killing power to Hela non-relevant to bladder tumor histopathologically as compared with EJ cells (P < 0.05). Conclusion: The DC pulsed by HSP70 derived from the autologous tumor cells could induce a peptide complexes specific CTL response to tumor cells, and the CTL response induced by the DC/HSP70 was stronger, which display the basis of the possible clinical application of DC/HSP70 for bladder tumor.     

In vitro immunization of patient T cells with autologous bone marrow antigen presenting cells pulsed with tumor lysates

Presentation of cell-associated antigen to T cells is a critical event in the initiation of an anti-tumor immune response but it appears to often be deficient or limiting. Here we report an experimental system for stimulation of human T lymphocytes using autologous antigen presenting cells (APCs) and autologous tumor cells. Two types of APCs were prepared from human bone marrow: MC and DC. MC were produced by using GM-CSF and SCF. DC were obtained with the same cytokines plus IL-4. DC and MC were generated in parallel from the same patients and their phenotypes and capacities to prime T lymphocytes were analyzed and compared. MC were CD14+, CD1a-, CD33+ and HLA-DR+. Two populations of DC were defined: immature DC were uniformly CD1a-; mature DC expressed CD1a, CD80, CD86, HLA-DR, CD54 and CD58 but lacked surface CD14. Stimulation of autologous T lymphocytes was studied by measuring their proliferation and cytotoxic function. In more than 80% of our experiments the proliferation of autologous T lymphocytes cocultured with APC pulsed or not with tumor cell lysates was higher than that of T cells cultured alone. DC were more effective than MC in stimulating proliferation of lymphocytes. The capacity of a patient's autologous bone marrow-derived APC to stimulate T cells when exposed to autologous tumor cell lysates suggest that such antigen-exposed APC may be useful in specific anti-tumor immunotherapy protocols.     

Activation of human T cells by a tumor vaccine infected with recombinant Newcastle disease virus producing IL-2

A new recombinant (rec) Newcastle disease virus (NDV) with incorporated human interleukin 2 (IL-2) as foreign therapeutic gene [rec(IL-2)] will be described. The foreign gene in rec(IL-2) did not affect the main features of NDV replication nor its tumor selectivity. Biologically active IL-2 was produced in high amounts by tumor cells infected with rec(IL-2). Tumor vaccine cells infected by rec(IL-2) stimulated human T cells to exert anti-tumor activity in vitro in a tumor neutralization assay. These effects were significantly increased when compared to vaccine infected by rec(-) virus without IL-2 gene. After incubation with rec(IL-2) infected tumor cells, T cells showed increased expression of the activation marker CD69 and produced increased amounts of IFNgamma when compared to T cells co-incubated with rec(-) infected tumor cells. CD8 T cells incubated with rec(IL-2) infected tumor cells showed upregulation of perforin, cell surface exposure of the degranulation marker CD107a and increased anti-tumor cytotoxic activity. Purified T cells from lymph nodes of head and neck squamous cell carcinoma (HNSCC) patients could be stimulated to secrete IFNgamma in an ELISPOT assay upon 40 h of stimulation with rec(IL-2) infected autologous tumor cells [ATV-rec(IL-2)] but not upon stimulation with rec(IL-2) infected allogeneic U937 tumor cells. This suggests direct activation of patient derived tumor antigen-specific memory T cells by ATV-rec(IL-2). In conclusion, the already inherent immunostimulatory properties of NDV could be further augmented by the introduction of the therapeutic gene IL-2. Active specific immunization of patients with ATV-rec(IL-2) should provide the microenvironment at the vaccination site with IL-2 and avoid side effects as seen after systemic IL-2 application.     

Human tumor cell infection by Newcastle Disease Virus leads to upregulation of HLA and cell adhesion molecules and to induction of interferons,chemokines and finally apoptosis

In order to analyse immune-stimulatory effects of infection of human tumor cells with Newcastle Disease Virus (NDV), gamma-irradiated human breast carcinoma, colon-carcinoma or glioblastoma cells from defined cell lines were modified either by true infection with live virus or by cell surface adsorption of UV-inactivated replication deficient virus. Modification with live but not inactive NDV induced in all human tumor cells IFN-beta and the chemokines RANTES and IFN-gamma-inducible protein-10 (IP-10). In addition, infection by live NDV induced upregulation of HLA-ABC-molecules in all tumor lines tested and HLA-DR molecules in breast carcinoma lines. Two cell adhesion molecules, ICAM-I (CD54) and LFA-3 (CD58), were also upregulated on human tumor cells after infection with live NDV. When infection of MCF-7 breast carcinoma cells by NDV was performed in the presence of neutralizing anti-IFN-beta antibodies no upregulation of HLA molecules was observed suggesting an important role of IFN-beta in this process. Forty-eight to 72 hours after infection of the irradiated tumor cells with live NDV, many tumor cells were dead or in early or late stages of apoptosis. These results provide explanations for the function of the virus-modified autologous tumor vaccine ATV-NDV with which promising clinical results have already been obtained.     

Differential expression of a recombinant adeno-associated virus 2 vector in human CD34+ cells and breast cancer cells

The use of autologous hematopoietic stem cell (HSC) grafts after high-dose chemotherapy protocols may be hampered by contamination of the grafts with tumor cells. Because epithelial cells seem to be the natural hosts of adeno-associated virus 2 (AAV-2), we speculated that epithelial tumor cells in HSC grafts might be selective targets for AAV-2-based vectors. To test this hypothesis, the breast cancer cell lines T47D and MCF-7 were infected with a recombinant AAV-2 vector expressing the green fluorescent protein (GFP) gene; in addition, human CD34+ mobilized peripheral progenitor cells were infected with the same vector. At a multiplicity of infection of 100, only 1.39% +/- 0.51% CD34+ cells expressed the GFP gene whereas, 36.06% +/- 6.53% of the infected T47D cells and 41.52% +/- 3.16% of the infected MCF-7 cells expressed the transduced GFP gene. After further optimizing the transduction procedure by using higher multiplicities of infection (100-500) and preincubation of samples with the tyrosine kinase inhibitor genistein, up to 82.52% and 85.35% GFP+ T47D and MCF-7 cells, respectively, were observed. The GFP fluorescence intensity in transduced mammary tumor cells was up to 3 logs higher than that of transduced CD34+ cells. The differential expression of recombinant AAV-2 vectors in hematopoietic and epithelial tumor cells warrants further research with this vector system, including the use of suicide genes for the purging of autologous HSC grafts.     

Effect of a caspase inhibitor, zVADfmk, on the inhibition of breast cancer cells by herpes simplex virus type 1

The oncolytic effects of herpes simplex virus-1 (HSV-1) are limited, possibly because of premature death of infected cells by apoptosis, which limits the amount of progeny virus that is produced. It has been proposed that inhibition of apoptosis in infected tumor cells would allow increased viral persistence, replication and therapeutic effect. To test this hypothesis, we infected monocyte chemoattractant factor-7 (MCF-7) and MDA-MB-231 breast cancer cells with HSV-1 strain 17(+) and 17Δγ34.5 in the presence or absence of N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVADfmk), a pan-caspase inhibitor. At low doses of HSV-1 strain 17(+) and 17Δγ34.5, the growth of MCF-7 cells was reduced to 37% or 42%, respectively, of uninfected cells. However, when cells were infected in the presence of zVADfmk, cell growth was further reduced to 24 and 33%. Similar results were seen in MDA-MB-231 cells. Cells treated with zVADfmk contained roughly 10 times more infectious viral particles than cells infected without zVADfmk, as shown by both plaque-forming and quantitative polymerase chain reaction assays. To model the situation within an infected tumor, supernatant fluids were collected from infected and non-infected cell cultures and then passed to non-infected cells. In the presence of zVADfmk, the cell growth inhibitory effect became stronger with repeated passages and was attributed to viral replication, because it could be prevented by anti-HSV antibody. These results suggest that caspases represent a novel target for drugs that increase the therapeutic efficacy of oncolytic herpes viruses against breast cancer.     

A study on melanoma treatment using dendritic cells loaded with antigens purified from melanoma cell lines

Objective The aim of this study was to purify effective tumor peptide complexes from human melanoma cell lines to enhance the treatment effects on melanoma.Methods We purified heat shock protein 70(HSP70)-peptide complexes(PCs)from human melanoma cell lines A375,A875,M21,M14,WM-35,and SK-HEL-1.We named the purified product as M-HSP70-PCs and determined its immunological activities.Autologous HSP70-PCs purified from primary tumor cells of melanoma patients(9 cases)were used as controls.These two tumor antigenic complexes were loaded into dendritic cells(DCs)and used to stimulate an antitumor response against tumor cells in the corresponding patients.Results Mature DCs pulsed with M-HSP70-PCs stimulated autologous T cells to secrete the same levels of type I cytokines as the autologous HSP70-PCs.Moreover,DCs pulsed with M-HSP70-PCs endued CIK cells with an equal ability as autologous HSP70-PCs to kill melanoma cells in the patients.Conclusion M-HSP70-PCs may be used as an efficient and generalized tumor antigen in the treatment of DC-based malignant melanoma.     

rhHSP70联合冻融抗原修饰树突状细胞诱导的抗乳腺癌作用

  目的   利用rhHSP70联合树突状细胞递呈肿瘤抗原的特性提高细胞毒T淋巴细胞（CTLs）对乳腺癌细胞的杀伤活性。   方法   外周血单个核细胞体外经GM-CSF和IL-4诱导产生树突状细胞,负载冻融抗原肽的同时加入新型热休克蛋白（rhHSP70）,不同分组分别诱导自体CTLs产生。ELISA测定CTLs杀伤活性和细胞因子的分泌。   结果   冻融抗原肽致敏的DCs促进CTLs增殖,上调CTLs中CD3+和CD8+T细胞群及Th1型细胞因子的分泌;体外实验中具有对人乳腺癌细胞MCF-7的杀伤活性,在加入rhHSP70后效果更加明显,并能显著增强CTLs对肿瘤细胞的杀伤率。   结论   hHSP70联合肝癌冻融抗原修饰DCs,能够促进DCs的成熟,增强DCs刺激淋巴细胞增殖的能力,诱导的CTLs在体外对乳腺癌细胞能产生高效杀伤力。rhHSP70增强DCs抗肿瘤能力的机制可能与其促进DCs成熟有关。       

Active specific immunotherapy of renal cell carcinoma: cellular and humoral immune responses

We investigated the effect of vaccinating renal cell carcinoma (RCC) patients with irradiated autologous or allogeneic tumor cells and Newcastle disease virus (NDV) as adjuvant on cellular and humoral antitumor immunity. By Western blot analysis, we found that vaccination induced antibody formation in 33 of 34 patients against NDV proteins but not against tumor cell related antigens. NDV proteins detected had molecular weights of 53 kDa, 55-56 kDa, and 66 kDa. ADCC by patients' isolated PBMC and patients' sera against autologous or allogeneic tumor cells was not enhanced after vaccine treatment in a nonradioactive cytotoxicity assay. Target cells infected with NDV were lysed more effectively (p < 0.05) in ADCC after vaccination than noninfected targets. Natural cellular cytotoxicity of patients' isolated PBMC was not altered during vaccine treatment. Specific lysis rates against autologous and allogeneic RCC cells not exceeded 10% (effector:target ratio 50:1). Specific lysis of K-562 cells was > 20%; a slight decrease in lysis during vaccination was not significant. Numbers of lymphocyte subsets from patients' peripheral blood analyzed by FACS revealed significant expression of CD20+ (p < 0.02) and CD39+ (p < 0.03) cell numbers by vaccine therapy. Cytokine detection in patients' sera by ELISA showed significant increases (p < 0.05) for IFN-gamma and TNF-alpha but not for IFN-alpha four h post vaccination. Thus, immunomodulation with autologous or allogeneic RCC tumor cell vaccines is mainly due to cytokine induction, whereas tumor specific humoral or cellular responses are not detectable in patients' peripheral blood.     

MGBA负载脐带血DC诱导特异性CTL对乳腺癌细胞的杀伤作用

目的：观察乳腺珠蛋白（mammaglobin A, MGBA）负载脐带血来源树突状细胞（dendritic cell, DC）诱导产生的细胞毒性T细胞（cytotoxic T lymphocyte, CTL）对乳腺癌细胞的体外杀伤效果。方法：采集健康剖宫产女性志愿者的脐带血,分离脐带血单个核细胞并诱导DC生成,用MGBA致敏DC与自体淋巴细胞共培养诱导CTL。采用流式细胞术测定DC的表型(CD83、CD86、HLADR)变化,ELISA法测定IL-10、IL-12分泌水平,CCK-8法测定CTL对乳腺癌细胞的杀伤活性。结果：成功培养出形态典型、功能成熟的DC,MGBA负载DC诱导的MGBA特异性CTL对乳腺癌细胞MDA-MB-415 产生显著的杀伤效果（P<0.05）;加入HLA-I 抗体可显著减弱杀伤效果,加入HLA-II 抗体细胞毒活性无显著变化,加入HLA-I 抗体或HLA-II 抗体对正常乳腺细胞的杀伤性均无影响。结论：MGBA 能明显加强脐带血DC 诱导的CTL 对乳腺癌细胞的杀伤活性,该杀伤活性具有MHC限制性。     

Dendritic cell vaccination in medullary thyroid carcinoma.

PURPOSE: Prognosis and treatment effectiveness for medullary thyroid carcinoma (MTC) are strictly related to tumor stage. Palliative treatment options show no significant benefit. A promising treatment approach for human cancer is based on the vaccination of autologous dendritic cells (DCs). EXPERIMENTAL DESIGN: The objective of this study was to evaluate the effectiveness of DC vaccines in MTC patients. Therefore, we generated autologous tumor lysate-pulsed DCs from 10 patients suffering from advanced MTC for repeated vaccination. Mature DCs were derived from peripheral blood monocytes by using CD14 magnetic bead selection and subsequent culture in the presence of granulocyte macrophage colony-stimulating factor, interleukin 4, and tumor necrosis factor alpha with or without addition of IFN-gamma. DCs were loaded with tumor lysate and further injected into a groin lymph node. Toxicity, tumor marker profile, immune response, and clinical response were determined. RESULTS: Vaccination was well tolerated and induced a positive immunological response in all of the tested patients as evaluated by in vivo delayed-type hypersensitivity reactivity or in vitro intracytoplasmic IFN-gamma detection assay. Three patients had a partial response, 1 patient presented a minor response, and 2 patients showed stable disease. The remaining 4 patients had progressive disease. CONCLUSIONS: These data provide strong evidence that vaccination with tumor-lysate pulsed DCs results in the induction of a specific immune response in patients suffering from MTC. Objective clinical responses could be observed even for far-advanced disease. Therefore, we suggest that MTC is particularly suited for DC-based immunotherapy.     

Dendritic cells, pulsed with lysate of allogeneic tumor cells, are capable of stimulating MHC-restricted antigen-specific antitumor T cells

A variety of approaches have been used to deliver tumor-associated antigens (TAA) in conjunction with dendritic cells (DC) as cellular adjuvants. DC derived from monocytic precursors have been pulsed with whole tumor antigen using a variety of strategies and have been demonstrated to induce CD4+ and CD8+ antitumor responses. In the present study, monocyte-derived DC have been pulsed with lysate from an allogeneic melanoma cell line, A-375, and used to repeatedly stimulate T cells. The resultant T cells were examined for cytotoxic activity against A-375 targets as well as the HLA A2-positive melanoma cell line DFW. Uptake of FITC-labeled melanoma lysate by DC established that lysate of melanoma cells was efficiently endocytosed. Stimulation with lysate-pulsed DC resulted in strong proliferative responses by T cells, which could be inhibited by antibodies against both MHC class I and class II. T cells stimulated in vitro with lysate-pulsed DC demonstrated potent cytotoxicity against the melanoma targets which were blocked by antibodies against MHC class I. Lysate-pulsed DC also elicited IFN-gamma secretion by T cells as measured in an ELISPOT assay. We have also examined the ability of lysate-pulsed DC to present melanoma-associated antigens to T cells. ELISPOT assays with synthetic peptides of melanoma-associated antigens, such as gp100, mage1, NY-ESO, and MART-1, revealed that lysate-pulsed DC could stimulate T cells in an antigen-specific manner. The results demonstrate that lysate from allogeneic tumor cells may be used as a source of antigens to stimulate tumor-specific T cells in melanoma.     

Recognition of breast cancer cells by CD8+ cytotoxic T-cell clones specific for NY-BR-1

Immunotherapy for breast cancer using cytotoxic T cells (CTL) is hindered by the lack of well-characterized breast cancer antigens that are expressed in most breast tumor cells and recognized by CD8+ CTL. A recently described breast tissue differentiation antigen, NY-BR-1, is expressed in >80% breast tumors and elicits a humoral response in a subset of breast cancer patients. To identify potential NY-BR-1 epitopes that are recognized by CTL, CD8+ T cells were stimulated in vitro with autologous dendritic cells pulsed with NY-BR-1 peptides that were predicted to bind to HLA-A2. In multiple normal female donors and breast cancer patients, specific CD8+ CTL responses were detected by enzyme-linked immunospot assay against several NY-BR-1 peptides after two cycles of stimulation. CD8+ CTL clones against three NY-BR-1 epitopes were isolated and recognized peptide-pulsed target cells with high avidity. T-cell clones specific for one of the NY-BR-1 epitopes (p904) also recognized breast tumor cells expressing NY-BR-1, NY-BR-1(-) cells transfected with a cDNA encoding the NY-BR-1 protein, and autologous dendritic cells pulsed with opsonized NY-BR-1+ breast tumor cells. Taken together, these results show that the p904 epitope derived from NY-BR-1 is efficiently processed and presented endogenously and identify NY-BR-1 as a promising target for T-cell-based immunotherapy for breast cancer.     

Enhanced T-cell immunity induced by dendritic cells with phagocytosis of heat shock protein 70 gene-transfected tumor cells in early phase of apoptosis

The dual role of heat shock protein 70 (HSP70), as antigenic peptide chaperone and danger signal, makes it especially important in dendritic cell (DC)-based vaccination. In this study, we investigated the impacts of apoptotic transgenic MCA/HSP tumor cells expressing HSP70 on DC maturation, T-cell stimulation and vaccine efficacy. We found that DCs with phagocytosis of MCA/HSP in early phase of apoptosis expressed more pMHC I complexes, stimulated stronger cytotoxic T lymphocyte (CTL) responses (40% specific killing at an E:T cell ratio of 50) and induced immune protection in 90% of mice against MCA tumor cell challenge, compared with 25% specific CTL killing activity and 60% immune protection seen in mice immunized with DC with phagocytosis of MCA/HSP in late phase of apoptosis (P<0.05). Similar results were confirmed in another EG7 tumor model also expressing HSP70. Taken together, our data demonstrate that HSP70 on apoptotic tumor cells stimulate DC maturation, and DC with phagocytosis of apoptotic tumor cells expressing HSP70 in early phase of apoptosis more efficiently induced tumor-specific CTL responses and immunity than DCs with phagocytosis of apoptotic tumor cells in late phase of apoptosis. These results may have an important impact in designing DC-based antitumor vaccines.     

Induction of systemic CTL responses in melanoma patients by dendritic cell vaccination: cessation of CTL responses is associated with disease progression.

Two HLA-A2-positive patients with advanced stage IV melanoma were treated with monocyte-derived dendritic cells (DC) pulsed with either tumor peptide antigens from gp100, MART-1 and MAGE-3 alone or in combination with autologous oncolysates. Clinically, the rapid progression of disease was substantially stalled and both patients were alive for more than 15 months after initiation of therapy. Specific CTL reactivity against several tumor antigens was detectable in peripheral blood, which declined just before reactivation of disease progression. Furthermore, CD3 zeta-chain expression detected by Western lotting was decreased in PBL at this time. In summary, our data confirm that DC-based vaccinations induce peptide-specific T cells in the peripheral blood of advanced-stage melanoma patients. Although successful induction of systemic tumor antigen-specific CTL may not lead to objective clinical tumor regression, their presence are indicative of a prolonged survival.