An ISCOM vaccine combined with a TLR9 agonist breaks immune evasion mediated by regulatory T cells in an orthotopic model of pancreatic carcinoma

Vaccines based on immune stimulatory complexes (ISCOM) induce T‐cell responses against tumor antigen (Ag). However, immune responses are impaired in pancreatic cancer patients. We investigated the efficacy of an ISCOM vaccine in a murine pancreatic carcinoma model. Panc02 cells expressing OVA as a model Ag were induced subcutaneously or orthotopically in the pancreas of C57BL/6 mice. Treatment consisted of an OVA containing ISCOM vaccine, either used alone or in combination with the TLR9 agonist CpG. The ISCOM vaccine effectively induced Ag‐specific CTL capable of killing tumor cells. However, in mice with established tumors CTL induction by the vaccine was inefficient and did not affect tumor growth. Lack of efficacy correlated with increased numbers of Treg. Depletion of Treg with anti‐CD25 mAb restored CTL induction and prolonged survival. Adding low‐dose CpG to the ISCOM vaccine reduced Treg numbers, enhanced CTL responses and induced regression of pancreatic tumors in a CD8⁺ T cell–dependent manner. Mice cured from the primary tumor mounted a memory T‐cell response against wild‐type Panc02 tumors, indicative of epitope spreading. Combining ISCOM vaccines with TLR agonists is a promising strategy for breaking tumor immune evasion and deserves further evaluation for the treatment of pancreatic carcinoma.     

Induction of CD4+ and CD8+ anti‐tumor effector T cell responses by bacteria mediated tumor therapy

Facultative anaerobic bacteria like E. coli can colonize solid tumors often resulting in tumor growth retardation or even clearance. Little mechanistic knowledge is available for this phenomenon which is however crucial for optimization and further implementation in the clinic. Here, we show that intravenous injections with E. coli TOP10 can induce clearance of CT26 tumors in BALB/c mice. Importantly, re‐challenging mice which had cleared tumors showed that clearance was due to a specific immune reaction. Accordingly, lymphopenic mice never showed tumor clearance after infection. Depletion experiments revealed that during induction phase, CD8⁺ T cells are the sole effectors responsible for tumor clearance while in the memory phase CD8⁺ and CD4⁺ T cells were involved. This was confirmed by adoptive transfer. CD4⁺ and CD8⁺ T cells could reject newly set tumors while CD8⁺ T cells could even reject established tumors. Detailed analysis of adoptively transferred CD4⁺ T cells during tumor challenge revealed expression of granzyme B, FasL, TNF‐α and IFN‐γ in such T cells that might be involved in the anti‐tumor activity. Our findings should pave the way for further optimization steps of this promising therapy.     

Co-immunization with L-Myc enhances CD8+ or CD103+ DCs mediated tumor-specific multi-functional CD8+ T cell responses

Renal carcinoma shows a high risk of invasion and metastasis without effective treatment. Herein, we developed a chitosan (CS) nanoparticle-mediated DNA vaccine containing an activated factor L-Myc and a tumor-specific antigen CAIX for renal carcinoma treatment. The subcutaneous tumor models were intramuscularly immunized with CS-pL-Myc/pCAIX or control vaccine, respectively. Compared with single immunization group, the tumor growth was significantly suppressed in CS-pL-Myc/pCAIX co-immunization group. The increased proportion and mature of CD11c⁺ DCs, CD8⁺CD11c⁺ DCs and CD103⁺CD11c⁺ DCs were observed in the splenocytes from CS-pL-Myc/pCAIX co-immunized mice. Furthermore, the enhanced antigen-specific CD8⁺ T lymphocyte proliferation, cytotoxic T lymphocyte (CTL) responses, and multi-functional CD8⁺ T cell induction were detected in CS-pL-Myc/pCAIX co-immunization group compared with CS-pCAIX immunization group. Of note, the depletion of CD8 T cells resulted in the reduction of CD8⁺ T cells or CD8⁺CD11c⁺ DCs and the loss of anti-tumor efficacy induced by CS-pL-Myc/pCAIX vaccine, suggesting the therapeutic efficacy of the vaccine was required for CD8⁺ DCs and CD103⁺ DCs mediated CD8⁺ T cells responses. Likewise, CS-pL-Myc/pCAIX co-immunization also significantly inhibited the lung metastasis of renal carcinoma models accompanied with the increased induction of multi-functional CD8⁺ T cell responses. Therefore, these results indicated that CS-pL-Myc/pCAIX vaccine could effectively induce CD8⁺ DCs and CD103⁺ DCs mediated tumor-specific multi-functional CD8⁺ T cell responses and exert the anti-tumor efficacy. This vaccine strategy offers a potential and promising approach for solid or metastatic tumor treatment.     

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.     

Induction of human papillomavirus oncogene‐specific CD8 T‐cell effector responses in the genital mucosa of vaccinated mice

Cervical cancer, the second leading cause of cancer mortality in women worldwide, results from infection with a subset of human papillomaviruses (HPV), HPV‐16 being the most prevalent type. The available prophylactic vaccines are an effective strategy to prevent this cancer in the long term. However, they only target 70–80% of all cervical cancers and cannot control existing HPV infections and associated lesions. Therapeutic vaccines are thus necessary for women who cannot benefit from prophylactic vaccination. Induction of protective immune responses in the genital mucosa (GM) may be crucial for efficacy of HPV therapeutic vaccines. We report here that mice that received a single subcutaneous (s.c.) vaccination of an adjuvanted long synthetic HPV16 E7_1–98 polypeptide showed induction of 100% tumor protection against s.c. TC‐1 tumors and that tumor regression was mainly provided by CD8 T cells. In vivo cytotoxic assay revealed high E7‐specific cytolytic T lymphocytes activity in spleen and in genital draining lymph nodes (LN), and E7‐specific CD8 T cells could be detected in GM by tetramer staining. More importantly, high‐avidity E7‐specific INF‐γ secreting CD8 T cells were induced not only in blood, spleen and LN but also in GM of vaccinated mice, thus providing evidence that a parenteral vaccination may be sufficient to provide regression of genital tumors. In addition, there was no correlation between the responses measured in blood with those measured in GM, highlighting the necessity and relevance to determine the immune responses in the mucosa where HPV‐tumors reside.     

结直肠癌患者CD4+、CD8+T淋巴细胞介导免疫功能的影响因素

目的:探讨结直肠癌患者(colorectal cancer,CRC)CD4+、CD8+T淋巴细胞介导的细胞免疫功能与术前检查肿瘤标记物,患者术前基础疾病和一般情况之间的关系,研究发现影响CRC细胞免疫功能的高危因素。方法:收集2010年02月至2020年06月广西科技大学第二附属医院普通外科218例CRC患者完整的细胞免疫,肿瘤标志物,患者术前基础疾病和一般情况等资料,对数据进行统计描述,临床上界定各检验指标的正常值范围:细胞免疫CD4+和CD4+/CD8+的正常值分别为320~1 250个/μL和0.9~2.0;肿瘤标记物CEA,CA199,CA125,CA153,CA242,CA724的正常值范围分别为0~5 μg/L,0~37 μg/L,0~35 μg/L,0~31.3 μg/L,0~20 μg/L,0~5.7 μg/L。临床上常以患者外周血液检测中的CD4+T淋巴细胞计数或CD4+/CD8+比值低于正常值范围定义为患者的细胞免疫功能低下。对其进行回顾性研究分析,采用统计学SPSS 24.0统计软件,对计量资料用P-P图做正态性检验,对数据先进行单因素分析,有统计学意义的因素进入多因素二元Logistic回归分析的方法,研究发现结直肠癌患者CD4+、CD8+T淋巴细胞介导的细胞免疫功能与各临床参数之间的关系。结果:男性的CD4+水平低于女性,差异有统计学意义（P＜0.05）。血型对细胞免疫功能影响无统计学差异（P＞0.05）。CEA和CA199升高组CD4+水平均低于正常组,差异有统计学意义（P＜0.05）。年龄、T分期、术前心血管病分组、呼吸系统疾病分组的患者细胞免疫功能低下率差异无统计学意义（P＞0.05）。术前患有糖尿病患者细胞免疫功能低下率高于术前未患糖尿病患者,差异有统计学意义（P＜0.01）,术前有吸烟史患者细胞免疫功能低下率高于术前无吸烟史患者,差异有统计学意义（P＜0.01）。CRC细胞免疫功能影响因素的二元Logistic多因素回归分析:术前糖尿病史和术前有吸烟史是导致细胞免疫功能低下的危险因素(OR=5.372,95%CI:2.656~10.865,P＜0.001;OR=4.467,95%CI:2.105~9.476,P＜0.001）。结论:术前有糖尿病史和术前有吸烟史是影响CRC的CD4+、CD8+T淋巴细胞介导的细胞免疫功能低下的独立危险因素,其中术前有吸烟史最显著。患者的性别,术前检查肿瘤标记物CEA和CA199水平对判断CRC细胞免疫功能有一定的参考价值。     

Stimulation of CD8+ T cell responses to MAGE-3 and Melan A/MART-1 by immunization to a polyvalent melanoma vaccine

A critical requirement for cancer vaccines is that they stimulate CD8⁺ T cell responses. In this study, we tested the ability of a polyvalent melanoma vaccine to induce CD8⁺ T cell responses to the melanoma associated antigens MAGE-3 and Melan A/MART-1. Fifteen HLA-A2⁺ patients with resected malignant melanoma were immunized with the vaccine s.c. every 2–3 weeks. CD8⁺ T cells in peripheral blood reacting to HLA-A2 restricted epitopes on MAGE-3 (FLWGPRALV) and Melan A/MART-1/(AAGIGILTV) were quantitated using a filter spot assay at baseline and following 4 immunizations. Vaccine immunization induced CD8⁺ T cells reacting to one or both of these peptides in 9 of the 15 (60%) patients. These cells were CD8⁺ and HLA-A2 restricted, as reactivity was abrogated by monoclonal antibodies (MAbs) to CD8 and class I HLA, but not by anti-CD4. All responding patients remained recurrence-free for at least 12 months (median 15 months, range 12 to >21 months), whereas melanoma recurred within 3–5 months in non-responders. The differences in outcome were unrelated to differences in disease severity or overall immunological competence between responders and non-responders. Our results demonstrate directly that MAGE-3 and Melan A/MART-1 can stimulate CD8⁺ T cell responses in humans, and suggest that these responses are protective and surrogate markers of vaccine efficacy. Int. J. Cancer 72:972–976, 1997. © 1997 Wiley-Liss, Inc.     

Antibody and CD8+ T cell responses against HER2/neu required for tumor eradication after DNA immunization with a Flt-3 ligand fusion vaccine.

PURPOSE: HER2/neu is frequently overexpressed in breast cancer. In a mouse model, vaccination with HER2/neu DNA elicits antibodies that confer partial protection against tumor challenge. EXPERIMENTAL DESIGN: To enhance antitumor immunity, we fused cDNA encoding Flt-3 ligand (FL) to the rat HER2/neu extracellular domain (neu), generating a chimeric FLneu molecule. FLneu and neu DNA vaccines were compared for immunogenicity and their ability to protect mice from tumor challenge. RESULTS: The neu vaccine generated a HER2/neu-specific antibody response. In contrast, vaccination with FLneu induced CD8+ T cells specific for HER2/neu but a negligible anti-HER2/neu antibody response. The switch from an antibody-mediated to T cell-mediated response was due to different intracellular localization of neu and FLneu. Although the neu protein was secreted, the FLneu protein was retained inside the cell, co-localizing with the endoplasmic reticulum, facilitating processing and presentation to T cells. The neu and FLneu vaccines individually conferred only weak tumor immunity. However, efficient tumor rejection was seen when neu and FLneu were combined, inducing both strong anti-HER2/neu-specific antibody and T cell responses. Adoptive transfer of both immune CD8+ T cells and immune sera from immunized mice was required to confer tumor immunity in na?ve hosts. CONCLUSIONS: These results show that active induction of both humoral and cellular immunity to HER2/neu is required for efficient tumor protection, and that neither response alone is sufficient.     

Diverse CD8+ T-cell responses to renal cell carcinoma antigens in patients treated with an autologous granulocyte-macrophage colony-stimulating factor gene-transduced renal tumor cell vaccine

A phase I clinical trial with granulocyte-macrophage colony-stimulating factor tumor cell vaccines in patients with metastatic renal cell carcinoma (RCC) showed immune cell infiltration at vaccine sites and delayed-type hypersensitivity (DTH) responses to autologous tumor cells indicative of T-cell immunity. To further characterize RCC T-cell responses and identify relevant RCC-associated antigens, we did a detailed analysis of CD8+ T-cell responses in two vaccinated RCC patients who generated the greatest magnitude of DTH response and also displayed a strong clinical response to vaccination (>90% reduction in metastatic tumor volume). Three separate CD8+ T-cell lines (and subsequent derived clones) derived from patient 24 recognized distinct RCC-associated antigens. One recognized a shared HLA-A*0201-restricted antigen expressed by both renal cancer cells and normal kidney cells. This recognition pattern correlated with a positive DTH test to normal kidney cells despite no evidence of impairment of renal function by the patient's remaining kidney after vaccination. A second line recognized a shared HLA-C7-restricted antigen that was IFN-gamma inducible. A third line recognized a unique HLA-A*0101-restricted RCC antigen derived from a mutated KIAA1440 gene specific to the tumor. In addition, two independent CTL lines and three clones were also generated from patient 26 and they recognized autologous tumor cells restricted through HLA-A*0205, HLA-A/B/C, and HLA-B/C. These results show that paracrine granulocyte-macrophage colony-stimulating factor tumor vaccines may generate a diverse repertoire of tumor-reactive CD8+ T-cell responses and emphasize the importance of polyvalency in the design of cancer immunotherapies.     

CXCR3 as a molecular target in breast cancer metastasis: inhibition of tumor cell migration and promotion of host anti-tumor immunity

Chemokines and chemokine receptors have critical roles in cancer metastasis and have emerged as one of the targeting options in cancer therapy. However, the treatment efficacy on both tumor and host compartments needs to be carefully evaluated. Here we report that targeting CXCR3 decreased tumor cell migration and at the same time improved host anti-tumor immunity. We observed an increased expression of CXCR3 in metastatic tumor cells compared to those from non-metastatic tumor cells. Knockdown (KD) of CXCR3 in metastatic tumor cells suppressed tumor cell migration and metastasis. Importantly, CXCR3 expression in clinical breast cancer samples correlated with progression and metastasis. For the host compartment, deletion of CXCR3 in all host cells in 4T1 mammary tumor model significantly decreased metastasis. The underlying mechanisms involve a decreased expression of IL-4, IL-10, iNOs, and Arg-1 in myeloid cells and an increased T cell response. IFN-γ neutralization diminished the metastasis inhibition in the CXCR3 knockout (KO) mice bearing 4T1 tumors, suggesting a critical role of host CXCR3 in immune suppression. Consistently, targeting CXCR3 using a small molecular inhibitor (AMG487) significantly suppressed metastasis and improved host anti-tumor immunity. Our findings demonstrate that targeting CXCR3 is effective in both tumor and host compartments, and suggest that CXCR3 inhibition is likely to avoid adverse effects on host cells.     

A tumor lysate is an effective vaccine antigen for the stimulation of CD4+ T-cell function and subsequent induction of antitumor immunity mediated by CD8+ T cells

To develop a potent cancer vaccine, it is important to study how to prepare highly immunogenic antigens and to identify the most appropriate adjuvants for the antigens. Here we show that a tumor lysate works as an effective antigen to prime CD4⁺ T-cell help when baculovirus is employed as an adjuvant. When immunized intradermally with the combination (BLP) of baculovirus, a CT26 tumor lysate, and a cytotoxic T-cell epitope peptide before a tumor challenge, 60% of mice rejected tumors. In contrast, all mice vaccinated with baculovirus plus a tumor lysate (BL) developed tumors. In addition, flow cytometry showed that tumor-specific, interferon γ-producing CD8⁺ cytotoxic T lymphocytes (CTLs) were robustly activated by intradermal immunization with BLP. When BLP was administered therapeutically to tumor-bearing mice, antitumor efficacy was better compared to BL. The established tumor was completely eradicated in 50–60% of BLP-treated mice, and induction of tumor-specific CTLs was observed, suggesting that the antitumor efficacy of BLP is mediated by CD8⁺ T cells. Numerous CD4⁺ T cells infiltrated the tumors of BLP-treated mice, whereas the antitumor effect of BLP almost disappeared after removal of the tumor lysate from BLP or after depletion of BLP-immunized mice of CD4⁺ T cells. Thus, the combination of a peptide, lysate, and baculovirus provides stronger antitumor immunity than does a peptide plus baculovirus or a lysate plus baculovirus; effectiveness of BLP is determined by functioning of CD4⁺ T cells stimulated with a tumor lysate.     

Ablation of the endoplasmic reticulum stress kinase PERK induces paraptosis and type I interferon to promote anti-tumor T cell responses

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Neuromedin U regulates the anti-tumor activity of CD8+ T cells and glycolysis of tumor cells in the tumor microenvironment of pancreatic ductal adenocarcinoma in an NMUR1-dependent manner

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with a poor prognosis, which is lethal in approximately 90% of cases despite advanced standard therapies. A typical feature of PDAC is the immunosuppressive tumor microenvironment with multiple immunosuppressive factors including neurotransmitters. Recently, neuromedin U (NMU), a highly conserved neuropeptide with many physiological functions, has attracted attention for its roles in tumorigenesis and metastasis in several types of cancers. However, whether NMU affects PDAC progression remains unclear. In this study, using an orthotopic mouse model of PDAC in combination with bioinformatics analysis, we found that NMU was upregulated in tumor tissues from the patients with PDAC and positively correlated with a poor prognosis of the disease. Interestingly, knockout of the Nmu gene in mice enhanced the anti-tumor functions of tumor-infiltrating CD8⁺ T cells in an NMU receptor 1-dependent manner. Additionally, NMU promoted the glycolytic metabolism of mouse PDAC tumors. The activities of pyruvate kinase (PK) and lactate dehydrogenase (LDH), pivotal enzymes involved in the regulation of lactate production, were markedly reduced in tumor tissues from NMU-knockout mice. In vitro the presence of LDHA inhibitor can reduce the production of lactic acid stimulated by NMU, which can increase the anti-tumor activity of CD8⁺ T cells. Moreover, treatment of the pancreatic cancer cells with a phosphoinositide 3-kinase (PI3K) inhibitor diminished NMU-induced lactate production and the activities of PK and LDH, suggesting that NMU might regulate glycolysis via the PI3K/AKT pathway.     

Intratumoral CD8+ T cells with a tissue-resident memory phenotype mediate local immunity and immune checkpoint responses in breast cancer

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Soluble γc receptor attenuates anti‐tumor responses of CD8+ T cells in T cell immunotherapy

Previous studies have shown that soluble common γ‐chain (sγc) modulates CD4⁺ T cell immunity with antagonistic functions in γc cytokine signaling. However, the role of sγc in functional properties of effector CD8⁺ T cells has not been fully defined. In this study, we report a new mechanism by which the anti‐tumor activity of mouse CD8⁺ T cells is suppressed in sγc of their own producing. While sγc significantly inhibits cytotoxicity of CD8⁺ T cells, blocking sγc production by genetic modification leads to potentiated effector function of CD8⁺ T cells, establishing persistent CD8⁺ T cells. This is due to the modulation of IL‐2 and IL‐15 signaling, which is required for expansion and survival of CD8⁺ T cells as well as for optimal cytotoxic activity. More efficient management of tumor growth was achieved by an adoptive transfer of sγc‐deficient CD8⁺ T cells than that of wild‐type or sγc‐overexpressing CD8⁺ T cells. Blocking of IL‐2 and IL‐15 signaling by sγc attenuates the capacity of CD8⁺ T cells to mount an optimal response to the tumor, with both quantitative and qualitative effects on antigen‐specific CD8⁺ T cells. These results could have a critical implication for the generation and survival of optimal effector T cells for adoptive immunotherapy of cancer.     

Allorestricted T lymphocytes with a high avidity T‐cell receptor towards NY‐ESO‐1 have potent anti‐tumor activity

The cancer‐testis antigen NY‐ESO‐1 has been targeted as a tumor‐associated antigen by immunotherapeutical strategies, such as cancer vaccines. The prerequisite for a T‐cell‐based therapy is the induction of T cells capable of recognizing the NY‐ESO‐1‐expressing tumor cells. In this study, we generated human T lymphocytes directed against the immunodominant NY‐ESO‐1_157–165 epitope known to be naturally presented with HLA‐A*0201. We succeeded to isolate autorestricted and allorestricted T lymphocytes with low, intermediate or high avidity TCRs against the NY‐ESO‐1 peptide. The avidity of the established CTL populations correlated with their capacity of lysing HLA‐A2‐positive, NY‐ESO‐1‐expressing tumor cell lines derived from different origins, e.g. melanoma and myeloma. The allorestricted NY‐ESO‐1‐specific T lymphocytes displayed TCRs with the highest avidity and best anti‐tumor recognition activity. TCRs derived from allorestricted, NY‐ESO‐1‐specific T cells may be useful reagents for redirecting primary T cells by TCR gene transfer and, therefore, may facilitate the development of adoptive transfer regimens based on TCR‐transduced T cells for the treatment of NY‐ESO‐1‐expressing hematological malignancies and solid tumors. © 2009 UICC     

肿瘤抗原致敏树突状细胞疫苗治疗晚期恶性肿瘤的临床观察

目的:观察肿瘤抗原致敏人树突状细胞(dendritic cell,DC)疫苗治疗各类晚期恶性肿瘤的不良反应,初步观察其治疗疗效。方法:91例非小细胞肺癌、结直肠癌、恶性黑素瘤、肾癌、乳腺癌等晚期恶性肿瘤患者入组,均符合试验的纳入组及排除标准,签署知情同意书,并报医院伦理委员会审查批准。患者单采外周血单核细胞体外培育成DC,用抗原致敏后制备成DC疫苗回输,每周回输1次,3次定义为1个周期。结果:91例患者共接受96个周期疫苗治疗;不良反应主要表现为寒战、发热、肌肉酸痛、皮肤瘙痒、胸闷及一过性全身无力,大部分为自限性;76例进行疗效评价,无完全缓解(complete remission,CR)及部分缓解(partial remission,PR)病例,治疗后稳定(stable disease,SD)31例,进展(progression disease,PD)45例,临床获益率40.8%;85例患者获得随访资料,患者中位达进展时间(median time to progression,mTTP)为2.6个月,生存时间为0.9~30.6个月,中位生存时间为4.5个月,1年生存率为9.2%。结论:肿瘤抗原致敏人DC疫苗治疗各类晚期恶性肿瘤耐受性良好,亦可见临床获益,疫苗临床应用方法有待进一步探讨。     

Th9 Cells Represent a Unique Subset of CD4+ T Cells Endowed with the Ability to Eradicate Advanced Tumors

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