Antitumor activity of cytokine-induced killer cells in nude mouse xenograft model

Ingenol-3-Angelate Enhances the B Cell Inhibitory Potential of Mesenchymal Stem Cells, Leading to Marked Alleviation of Lupus Symptoms in MRL.faslpr Mice

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by autoantibody production by hyper-activated B cells. Although mesenchymal stem cells (MSCs) relieve lupus symptoms by inhibiting mainly T cells, whether MSCs also inhibit B cells has been controversial. Here, we found that naïve MSCs inhibited IFN-γ production by T cells, but not IgM production by B cells. We used a chemical approach to prime MSCs to inhibit B cells. We found that ingenol-3-angelate (I3A), a non-tumor-promoting phorbol ester, activated MSCs to inhibit B cells in a TGF-β1-dependent manner. We also showed that IL-1β induced MSCs to continuously secrete TGF-β1, which directly inhibited IgM production by B cells, whereas IL-1β did not. I3A-treated MSCs were better than naïve MSCs at ameliorating SLE symptoms in MRL.faslpr mice. In summary, our data provide information on how to generate MSCs that are effective for the treatment of SLE characterized by excessive B cell activation.

Immunophenotype and antitumor activity of cytokine-induced killer cells from patients with hepatocellular carcinoma

BACKGROUND

Cytokine-induced killer (CIK) cells are heterogeneous lymphocytes from human peripheral blood mononucleated cells (PBMCs) co-cultured with several cytokines. The main purpose of this study is to evaluate the functional characteristics and anticancer ability of CIK cells from hepatocarcinoma (HCC) patients.

METHODS

CIK cells were activated ex-vivo and expanded from PBMCs from HCC patients. The immunophenotype and the ex-vivo killing ability of CIK cells were evaluated. Human CIK cells were intravenously injected into NOD/SCID mice to evaluate the in vivo anticancer ability.

RESULTS

More than 70% of CIK cells were CD3+CD8+, and 15%-30% were CD3+CD56+. These cells expressed an increased number of activated natural killer (NK) receptors, such as DNAM1 and NKG2D, and expressed low-immune checkpoint molecules, including PD-1, CTLA-4, and LAG-3. Among the chemokine receptors expressed by CIKs, CXCR3 and CD62L were elevated in CD8+ T cells, representing the trafficking ability to inflamed tumor sites. CIK cells possess the ex-vivo anticancer activity to different cell lines. To demonstrate in vivo antitumor ability, human CIK cells could significantly suppress the tumor of J7 bearing NOD/SCID mice. Furthermore, human immune cells could be detected in the peripheral blood and on the tumors after CIK injection.

CONCLUSIONS

This study revealed that CIK cells from HCC patients possess cytotoxic properties, and express increased levels of effector NK receptors and chemokine molecules and lower levels of suppressive checkpoint receptors. CIK cells can suppress human HCC ex-vivo and in vivo. Future clinical trials of human CIK cell therapy for HCC are warranted.

Inhibition of glioma by adenovirus KGHV500 encoding anti-p21Ras scFv and carried by cytokine-induced killer cells

Ras gene mutation or overexpression can lead to tumorigenesis in multiple kinds of cancer, including glioma. However, no drugs targeting Ras or its expression products have been approved for clinical application thus far. Adenoviral gene therapy is a promising method for the treatment of glioma. In this study, the human glioma cell line U251 was co-cultured with recombinant adenovirus KGHV500, and the anti-tumor effects of KGHV500 were determined by MTT, scratch test, Transwell invasion, and apoptosis assays. Then, KGHV500 was delivered via the intravenous injection of CIK cells into glioma xenografts. Tumor volume, ki67 proliferation index, apoptosis levels, and anti-p21Ras scFv expression were tested to evaluate targeting ability, anti-tumor efficacy, and safety. We found that the KGHV500 exhibited anti-tumor activity in U251 cells and increased the intracellular expression of anti-p21Ras scFv compared with that in the control groups. CIK cells delivered KGHV500 to U251 glioma cell xenografts and enhanced anti-tumor activity against glioma xenografts compared to that produced by the control treatment. In conclusion, targeting Ras is a useful therapeutic strategy for gliomas and other Ras-driven cancers, and the delivery of anti-p21Ras scFv by recombinant adenovirus and CIK cells may play an essential role in the therapy of Ras-driven cancers.

Recognition and killing of cancer stem-like cell population in hepatocellular carcinoma cells by cytokine-induced killer cells via NKG2d-ligands recognition

There is an urgent need for more potent and safer approaches to eradicate cancer stem cells (CSCs) for curing cancer. In this study, we investigate cancer-killing activity (CKA) of cytokine-induced killer (CIK) cells against CSCs of hepatocellular carcinoma (HCC). To visualize CSCs in vitro by fluorescence imaging, and image and quantify CSCs in tumor xenograft-bearing mice by bioluminescence imaging, HCC cells were engineered with CSC detector vector encoding GFP and luciferase controlled by Nanog promoter. We found that CIK cells have a strong CKA in vitro against putative CSCs of HCC, as shown by tumorsphere formation and time-lapse imaging. Additionally, time-lapse recording firstly revealed that putative CSCs were attacked simultaneously by many CIK cells and finally eradicated by CIK cells, indicating the necessity of achieving sufficient effector-to-target ratios. We firstly illustrated that anti-NKG2D antibody blocking partially but significantly inhibited CKA of CIK cells against putative CSCs. More importantly, intravenous infusion of CIK cells remarkably delayed tumor growth in mice with a significant decrease in putative CSC number monitored by bioluminescence imaging. Taken together, these findings demonstrate CKA of CIK cells against putative CSCs of HCC, at least in part, by NKG2D-ligands recognition.

Cytokine-induced killer cells as immunotherapy for solid tumors: current evidence and perspectives

Cytokine-induced killer (CIK) cells are ex vivo expanded T lymphocytes endowed with potent MHC-independent antitumor activity. CIK cells are emerging as promising therapeutic approach in the field of cancer adoptive immunotherapy, with biologic features favoring their transferability into clinical applications. Aim of this review is to present the biologic characteristic of CIK cells, discussing the main preclinical findings and initial clinical applications in the field of solid tumors.

Cytokine-induced killer cells: A novel immunotherapy strategy for leukemia

Cytokine-induced killer (CIK) cells are NK-like T cells derived from peripheral blood mononuclear cells that are co-stimulated and expanded using cytokines for 14–21 days in vitro. CIK cells are a heterogeneous subset of highly-efficient cytotoxic T effector cells that mediate major histocompatibility complex-unrestricted cytotoxicity against a broad array of tumor cells. These effector cells are generated from patients with leukemia or healthy donors who demonstrate similar cytotoxic activity against leukemia blasts. Allogeneic CIK cells retain the ability to produce the graft versus tumor response and generate minimal graft versus host disease. In addition, CIK cells possess no cytotoxicity against normal hematopoietic stem cells in vivo. Leukemia recurrence remains a formidable obstacle, but adoptive immunotherapy offers promise for the eradication of minimal residual disease and prevention of leukemia relapse following hematopoietic stem cell transplantation. CIK cell infusion started a novel generation of adoptive immunotherapy and exhibits particular potential applications in the area of hematological malignancy. In the present study, the previous strategies of leukemia immunotherapy using CIK cells are reviewed and the future directions of development are discussed.

Combined immunotherapy with dendritic cells and cytokine-induced killer cells for malignant tumors: a systematic review and meta-analysis

PURPOSE

A new strategy of adoptive and passive immunotherapy involves combining dendritic cells (DCs) with a subset of natural killer T lymphocytes termed cytokine-induced killer (CIK) cells. The objective of this systematic review and meta-analysis was to evaluate the safety and efficacy of DC-CIK therapy vs. placebo, no intervention, conventional treatments, or other complementary and alternative medicines for malignant tumors.

METHOD

We searched PubMed, Medline, Embase, Cochrane, Wangfang, Weipu, CNKI databases and reference lists of articles. We selected randomized controlled trials of DC-CIK therapy vs. placebo, no intervention, conventional treatments, or other complementary and alternative medicines in patients with all types and stages of malignant tumor. Primary outcome measures were overall survival and treatment response. Secondary outcome measures were health-related quality of life (HRQoL) assessment, progression free survival (PFS), and adverse events.

RESULTS

Six trials met our inclusion criteria. There was evidence that chemotherapy+DC-CIK increased the 2-year (RR 2.88, 95% CI 1.38 to 5.99, P=0.005) and 3-year (RR 11.67, 95% CI 2.28 to 59.69, P=0.003) survival rates and progression free survival (RR 0.64, 95% CI 0.34 to 0.94, P<0.0001) in patients with non-small cell lung cancer compared to those treated with chemotherapy alone. DC-CIK therapy appears to be well-tolerated by cancer patients and to improve post-treatment patient health related quality of life.

CONCLUSION

DC-CIK immunotherapy is a safe and effective treatment for patients with malignant tumors. Further clinical trials to provide supportive evidence for the routine use of DC-CIK therapy in clinical practice are warranted.

Effects of two different immunotherapies on triple negative breast cancer in animal model

The ability of immune system to react specifically against tumors inspirited the study of triple negative breast cancer (TNBC) immunotherapies. Sixty spontaneous breast cancer TA2 mice were randomly divided into three groups: GM-CSF group, with therapy of granulocyte-macrophage colony-stimulating factor (GM-CSF) combined with breast cancer stem cells associated antigens and cytosine-phosphorothioate-guanine oligodeoxynucleotides (CpG-ODNs); DC-CIK group, with infusions of dendritic cells/cytokine-induced killer (DC/CIK) cells; and PBS group as controls. After therapy, the cellular immunity of mice in GM-CSF group and DC-CIK group was obviously increased, especially for GM-CSF group (P<0.05), tumor regression was obviously observed in GM-CSF group. The survival rate of mice in GM-CSF group was significantly higher compared to DC-CIK group and PBS group. These results indicated that tumor immunotherapy manifested strong killing activity against TNBC. The therapeutic effect of GM-CSF combined with antigens and CpG was better than DC-CIK cells.

Intraperitoneal perfusion of cytokine-induced killer cells with local hyperthermia for advanced hepatocellular carcinoma

AIM: To study the effect and tolerance of intraperitoneal perfusion of cytokine-induced killer (CIK) cells in combination with local radio frequency (RF) hyperthermia in patients with advanced primary hepatocellular carcinoma (HCC).

METHODS: Patients with advanced primary HCC were included in this study. CIK cells were perfused intraperitoneal twice a week, using 3.2 × 10⁹ to 3.6 × 10⁹ cells each session. Local RF hyperthermia was performed 2 h after intraperitoneal perfusion. Following an interval of one month, the next course of treatment was administered. Patients received treatment until disease progression. Tumor size, immune indices (CD3⁺, CD4⁺, CD3⁺CD8⁺, CD3⁺CD56⁺), alpha-fetoprotein (AFP) level, abdominal circumference and adverse events were recorded. Time to progression and overall survival (OS) were calculated.

RESULTS: From June 2010 to July 2011, 31 patients diagnosed with advanced primary HCC received intraperitoneal perfusion of CIK cells in combination with local RF hyperthermia in our study. Patients received an average of 4.2 ± 0.6 treatment courses (range, 1-8 courses). Patients were followed up for 8.3 ± 0.7 mo (range, 2-12 mo). Following combination treatment, CD4⁺, CD3⁺CD8⁺ and CD3⁺CD56⁺ cells increased from 35.78% ± 3.51%, 24.61% ± 4.19% and 5.94% ± 0.87% to 45.83% ± 2.48% (P = 0.016), 39.67% ± 3.38% (P = 0.008) and 10.72% ± 0.67% (P = 0.001), respectively. AFP decreased from 167.67 ± 22.44 to 99.89 ± 22.05 ng/mL (P = 0.001) and abdominal circumference decreased from 97.50 ± 3.45 cm to 87.17 ± 4.40 cm (P = 0.002). The disease control rate was 67.7%. The most common adverse events were low fever and slight abdominal erubescence, which resolved without treatment. The median time to progression was 6.1 mo. The 3-, 6- and 9-mo and 1-year survival rates were 93.5%, 77.4%, 41.9% and 17.4%, respectively. The median OS was 8.5 mo.

CONCLUSION: Intraperitoneal perfusion of CIK cells in combination with local RF hyperthermia is safe, can efficiently improve immunological status, and may prolong survival in HCC patients.

Inhibition of human pancreatic tumor growth by cytokine-induced killer cells in nude mouse xenograft model

Pancreatic cancer is the fourth commonest cause of cancer-related deaths in the world. However, no adequate therapy for pancreatic cancer has yet been found. In this study, the antitumor activity of cytokine-induced killer (CIK) cells against the human pancreatic cancer was evaluated in vitro and in vivo. Human peripheral blood mononuclear cells were cultured with IL-2-containing medium in anti-CD3 for 14 days. The resulting populations of CIK cells comprised 94% CD3⁺, 4% CD3^-CD56⁺, 41% CD3⁺CD56⁺, 11% CD4⁺, and 73% CD8⁺. This heterogeneous cell population was called cytokine-induced killer (CIK) cells. At an effector-target cell ratio of 100:1, CIK cells destroyed 51% of AsPC-1 human pancreatic cancer cells, as measured by the ⁵¹Cr-release assay. In addition, CIK cells at doses of 3 and 10 million cells per mouse inhibited 42% and 70% of AsPC-1 tumor growth in nude mouse xenograft assays, respectively. This study suggests that CIK cells may be used as an adoptive immunotherapy for pancreatic cancer patients.

In vivo distribution and antitumor effect of infused immune cells in a gastric cancer model

Adoptive cellular transfer has been employed for cancer immunotherapy, including patients with gastric cancer. However, little is known about the distribution of effector cells after their injection via different pathways. In this study, we used human gastric cancer cells (BGC823) tagged with enhanced green fluorescent protein (EGPF) to establish a subcutaneous gastric cancer model in nude mice. Cytokine-induced killer (CIK) cells and cytotoxic T lymphocytes (CTLs) were generated from human peripheral blood and labeled with red fluorescent PKH26. A portion of CIK cells was armed with CEA/CD3-bispecific single-chain antibody. When CIK cells were injected into nude mice with established subcutaneous gastric cancer via peritumoral (p.t.), intravenous (i.v.) and intraperitoneal (i.p.) infusion respectively, the distribution of cells was observed using a live fluorescence imaging system. We found that only a very small number of CIK cells could travel to the tumor site after i.p. or i.v. infusion, and they inhibited subcutaneous tumor growth in vivo only immediately following injection. In contrast, p.t. injection resulted in a significantly higher accumulation of CIK cells at the tumor site for 48 hours and mediated the greatest tumor inhibition compared with the other two injection methods. In addition, we compared the antitumor activity of CIK, CEA/CD3-bscAb-CIK and CTL cells in vitro and in vivo after p.t. injection. Among the three types of immune cells, CTLs demonstrated the strongest antitumor activity both in vitro and in vivo. CEA/CD3-bispecific single chain antibody could effectively link T lymphocytes and tumor cells expressing CEA, and resulted in significantly higher accumulation of CIK cells at the tumor site compared with the parental CIK cells. This study indicates that peritumoral injection of immune effector cells by minimally invasive surgical procedures represents an effective delivery method of adoptive cellular immunotherapy. Tumor-specific immune cells, such as CTLs, are a better choice of effector cells than CIKs in cellular immunotherapy. Furthermore, CD3+ immune cells armed with the CEA/CD3-bispecific single chain antibody could more effectively travel to and accumulate at the site of tumors expressing CEA, such as gastric cancer.

Dynamic tracing of immune cells in an orthotopic gastric carcinoma mouse model using near-infrared fluorescence live imaging

Adoptive cellular immunotherapy (ACI) has been demonstrated to be a promising cancer therapeutic, however, the distribution of immune cells injected into a tumor-bearing body is unclear. In this study, we investigated the tumor-targeting capacity of cytokine-induced killer (CIK) cells and cytotoxic T lymphocytes (CTLs) in a human gastric carcinoma orthotopic mouse model using a near-infrared fluorescence imaging system. CIK cells and tumor-specific CTLs were prepared with the near-infrared fluorescent dye DiR. As expected, no significant change in the proliferation rate or antitumor activity of CIK cells and CTLs was noted after labeling with DiR. Furthermore, a gastric carcinoma orthotopic model was established using a fibrinogen-thrombin method in nude mice followed by intraperitoneal infusion of the labeled immune cells into nude mice with established gastric carcinoma. Dynamic tracing of the immune cells was performed using a fluorescence-based live imaging system. Concentrated fluorescence signals were observed for a minimum of two weeks at the tumor site in mice infused with either CIK cells or CTLs with a peak signal at 48 h. Notably, CTLs were more persistent at the tumor site and exhibited a more intense antitumor activity than CIK cells following infusion. These results provided visual evidence of the tumor-targeting capacity of immune cells in live animals.

Cytokine-induced killer (CIK) cells as feasible and effective adoptive immunotherapy for the treatment of solid tumors

INTRODUCTION

Cytokine-induced killer (CIK) cells are heterogeneous ex vivo-expanded T lymphocytes with mixed T-NK phenotype and endowed with a wide MHC-unrestricted antitumor activity. CIK cells can be expanded from peripheral blood mononuclear cells (PBMC) cultured with the timed addition of IFN-γ, Ab anti-CD3 and IL2. A consistent subset of mature CIK cells presents a CD3(+)CD56(+) phenotype. The CD3(+)CD56(+) cellular subset is the main responsible for the tumor-killing activity, mostly mediated by the interaction of NKG2D receptor with MHC-unrestricted ligands (MIC A/B; ULBPs) on tumor cells.

AREAS COVERED

In the present work, we described the biologic characteristics of CIK cells, focusing on those aspects that may favor their clinical translation. We reviewed preclinical data and analyzed reports from clinical trials. A specific paragraph is dedicated to future research perspectives in the field.

EXPERT OPINION

CIK cells represent a realistic new option in the field of cancer immunotherapy. Crucial issues, favoring their clinical translation, are the easy availability of large amounts of expanded CIK cells and their MHC-unrestricted tumor killing, potentially effective against many tumor types. Intriguing future perspectives and open challenges are the investigation of synergisms with other immunotherapy approaches, targeted therapies or even conventional chemotherapy.

Cytotoxic Capacity of IL-15-Stimulated Cytokine-Induced Killer Cells Against Human Acute Myeloid Leukemia and Rhabdomyosarcoma in Humanized Preclinical Mouse Models

Allogeneic stem cell transplantation (allo-SCT) has become an important treatment modality for patients with high-risk acute myeloid leukemia (AML) and is also under investigation for soft tissue sarcomas. The therapeutic success is still limited by minimal residual disease (MRD) status ultimately leading to patients' relapse. Adoptive donor lymphocyte infusions based on MRD status using IL-15-expanded cytokine-induced killer (CIK) cells may prevent relapse without causing graft-versus-host-disease (GvHD). To generate preclinical data we developed mouse models to study anti-leukemic- and anti-tumor-potential of CIK cells in vivo. Immunodeficient mice (NOD/SCID/IL-2Rγc(-), NSG) were injected intravenously with human leukemic cell lines THP-1, SH-2 and with human rhabdomyosarcoma (RMS) cell lines RH41 and RH30 at minimal doses required for leukemia or tumor engraftment. Mice transplanted with THP-1 or RH41 cells were randomly assigned for analysis of CIK cell treatment. Organs of mice were analyzed by flow cytometry as well as quantitative polymerase chain reaction for engraftment of malignant cells and CIK cells. Potential of CIK cells to induce GvHD was determined by histological analysis. Tissues of the highest degree of THP-1 cell expansion included bone marrow followed by liver, lung, spleen, peripheral blood (PB), and brain. RH30 and RH41 engraftment mainly took place in liver and lung, but was also detectable in spleen and PB. In spite of delayed CIK cell expansion compared with malignant cells, CIK cells injected at equal amounts were sufficient for significant reduction of RH41 cells, whereas against fast-expanding THP-1 cells 250 times more CIK than THP-1 cells were needed to achieve comparable results. Our preclinical in vivo mouse models showed a reliable 100% engraftment of malignant cells which is essential for analysis of anti-cancer therapy. Furthermore our data demonstrated that IL-15-activated CIK cells have potent cytotoxic capacity against AML and RMS cells without causing GvHD.

New adoptive immunotherapy strategies for solid tumours with CIK cells

INTRODUCTION

Despite development and introduction of new and innovative drugs, a large number of malignant diseases are associated with unfavourable prognosis. In recent years, considerable progress in cancer treatment has been obtained by the application of cytokine-induced killer (CIK) cells.

AREAS COVERED

This review provides an overview and summary of recent advances in adoptive immunotherapy strategies in cancer treatment using CIK cells. A selective literature search has been performed.

EXPERT OPINION

The application of CIK cells as adoptive immunotherapy plays an important role in cancer treatment. Combining CIK cells with other conventional and established therapy options represents an innovative approach and will hopefully provide new insight for the future.

Preconditioning chemotherapy with cisplatin enhances the antitumor activity of cytokine-induced killer cells in a murine melanoma model

Accumulating evidence has indicated that preconditioning chemotherapy could eliminate the suppressive factors in antitumor immune response, thereby leading to the full release of the efficacy of the subsequent immunotherapy. In this study, a single subtoxic dose (5 mg/kg, intraperitoneally) of cisplatin was chosen as the preconditioning chemotherapy in combination with cytokine-induced killer (CIK) cells (4×10(6), intravenously) to treat the murine B16 melanoma xenografts. It was found that cisplatin pretreatment could enhance the antitumor activity of CIK cells. To explore the potential mechanisms underlying the efficacy-enhancing effect of cisplatin, the in vivo trafficking and distribution of the infused CIK cells were traced. It was found that cisplatin could augment the homing ability of CIK cells into the tumor, tumor-draining lymph nodes (TDLNs), and spleen tissues. The endogenous effector cells, CD3(+) T lymphocytes also had an increased accumulation in the tumor and TDLNs after cisplatin precondition. Moreover, cisplatin could also modulate the percentages of myeloid cells, thus encouraging immune responses by increasing the percentages of dendritic cells and relieving the immunosuppression by preferentially eliminating the myeloid-derived suppressor cells. In conclusion, our findings suggested that cisplatin preconditioning chemotherapy could enhance the antitumor activity of CIK cells in a murine melanoma model, and this efficacy-enhancing effect was attributed to the augmented homing ability of exogenous and endogenous effector cells and the modulation of the myeloid cells.

Cytokine induced killer cells as promising immunotherapy for solid tumors

Cytokine-induced killer (CIK) cells are a heterogeneous subset of ex-vivo expanded T lymphocytes which present a mixed T-NK phenotype and are endowed with a MHC-unrestricted antitumor activity. The main functional properties of CIK cells may address some of the main limitations that are currently preventing the successful clinical translation of adoptive immunotherapy strategies. Clinically adequate quantities of immune effectors, sufficient for multiple adoptive infusions, may be obtained based on their relatively easy and inexpensive ex-vivo expansion starting from peripheral blood mononuclear cells. The MHC-unrestricted tumor-killing is mainly based on the interaction between NKG2D molecules on CIK cells and MIC A/B or ULBPs molecules on tumor cells; it has been proved effective against several solid and hematological malignancies and does not require any HLA-restriction increasing the number of patients that might potentially benefit from such approach. Finally, CIK cells present a reduced alloreactivity across HLA-barriers with important clinical implications for their potential use as alternative to conventional Donor Lymphocyte Infusions after allogeneic hemopoietic cell transplant with a reduced risk of GVHD. In the present report we review the main functional characteristics of CIK cells discussing recent findings and future perspectives to improve their antitumor activity and potential clinical applications.

Combining cytokine-induced killer cells with vaccination in cancer immunotherapy: more than one plus one?

The immune system can be harnessed to fight cancer by active (stimulating the patient's intrinsic immune response to cancer) and by passive (transfer of active humoral or cellular immunity) immunotherapy. While for each strategy proof-of-principle was provided, clinical benefit was limited likely due to malfunction of lymphocytes. Increasing knowledge of both the mechanism of vaccination through dendritic cells (DCs) and the potency of a subset of natural killer T lymphocytes termed cytokine-induced killer (CIK) cells led to new strategies through combining adoptive and passive immunotherapy. This review summarizes most recent clinical trials indicating that CIK cells can substantially enhance the effect of tumor vaccines and discusses the potential therapeutic benefit in the long-term control of tumor progression.

Bone marrow mesenchymal stem cells reduce the antitumor activity of cytokine-induced killer/natural killer cells in K562 NOD/SCID mice

Adoptive cellular immunotherapy is an important treatment to eliminate residual tumor cells after hematopoietic stem-cell transplantation. Bone marrow mesenchymal stem cells (MSC) have previously been shown to exert immunoregulation functions, including inhibition of proliferation and killing activities of T cells and natural killer (NK) cells in vitro and reduction of the graft-versus-host disease. MSC can survive in vivo for a long period of time, the influence of MSC on the antitumor activity of subsequently infused immune killer cells is not clear. The aim of this study was to investigate the influences of MSC infused via different paths and at different times on the antitumor activities of cytokine-induced killer (CIK)/NK cells derived from umbilical cord blood in K562 NOD/SCID mice. The potential interaction mechanisms of MSC and CIK/NK cells infused through different paths using different intervals in vivo were subsequently explored. The results show that the antitumor activities of CIK/NK cells was inhibited by MSC when injected via the same path (tail vein), and the suppressive effect of MSC on CIK/NK cells were less pronounced when they were injected separately through different paths. There were no effects of MSC on the antitumor activities of CIK/NK cells if the MSC and CIK/NK cells were injected with a 48-h interval. Moreover, the suppressive effect continuous, even if MSC were infused 48 h earlier than CIK/NK cells. It suggests that pre-injected MSC can reduce the antitumor activities of CIK/NK cells in vivo. The probable mechanisms are that MSC and CIK/NK cells might have a greater opportunity to meet and interact if they are injected simultaneously via the same path. The suppression of MSC on CIK/NK cells in vivo mainly takes place in the reticuloendothelial system, including the lung and the liver.

Coculturing dendritic cells with zoledronate acid efficiently enhance the anti-tumor effects of cytokine-induced killer cells

INTRODUCTION

Dendritic cells (DCs) have greater stimulating activity on innate and adaptive immunity following short-term sensitization with zoledronate acid (DCs(Zol)). We identified the phenotype, cytotoxicity, and mechanisms of killing of cytokine-induced killer (CIK) cells which were cocultured with DCs(Zol).

METHODS

Adherent and nonadherent cells of peripheral blood mononuclear cell from myeloma patients were incubated for DCs and CIK cells. Then, the CIK cells were cocultured with DCs(Zol) (DCs(Zol)-CIK). Expression of markers for DCs(Zol)-CIK cells was measured using flow cytometry. Cytotoxicity was evaluated by against human myeloma cell lines and mechanisms of killing were tested by selectively blocking NKG2D receptor. The anti-tumor activity of these effector cells was further evaluated using a nude mice tumor model.

RESULTS

gammadelta TCR expression of CIK cells significantly increased after coculture with immature or mature DCs(Zol) (iDCs/mDCs(Zol)-CIK) and these cells aggressively lysed myeloma cells compared with mDCs-CIK and zoledronate acid pulsed CIK cells (CIK(Zol); 50.8 +/- 7.9% and 48.2 +/- 4.7% versus 31.9 +/- 5.1% and 20.5 +/- 3.6%, effector versus target ratio was 60:1). Both alphabeta T and gammadelta T cells in the iDCs(Zol)-CIK cells performed the majority of lysis. The iDCs/mDCs(Zol)-CIK cells greatly increased NKG2D expression compared with mDCs-CIK and CIK(Zol) during culture (71.5 +/- 11.3% and 67.7 +/- 9.3% versus 51.3 +/- 6.2% and 47.1 +/- 5.7%). iDCs(Zol)-CIK cell-mediated lysis dropped 69.21% when the NKG2D receptor was blocked and the cytotoxicity correlated with NKG2D ligand-MICA expression on the target cells. In a human myeloma bearing nude mice model, iDCs(Zol)-CIK and mDCs(Zol)-CIK cells treatment groups obtained 75% and 62.5% long-term survival (>120 days) respectively, as compared with none of the control animals or 37.5% treated with mDCs-CIK cells.

CONCLUSION

Large numbers of CIK cells with greater anti-tumor activities are rapidly generated by Zol-treated iDCs/mDCs. This strategy is worthy of further investigation to improve adoptive cell therapy against tumors.

Immunological considerations of modern animal models of malignant primary brain tumors

Recent advances in animal models of glioma have facilitated a better understanding of biological mechanisms underlying gliomagenesis and glioma progression. The limitations of existing therapy, including surgery, chemotherapy, and radiotherapy, have prompted numerous investigators to search for new therapeutic approaches to improve quantity and quality of survival from these aggressive lesions. One of these approaches involves triggering a tumor specific immune response. However, a difficulty in this approach is the the scarcity of animal models of primary CNS neoplasms which faithfully recapitulate these tumors and their interaction with the host's immune system. In this article, we review the existing methods utilized to date for modeling gliomas in rodents, with a focus on the known as well as potential immunological aspects of these models. As this review demonstrates, many of these models have inherent immune system limitations, and the impact of these limitations on studies on the influence of pre-clinical therapeutics testing warrants further attention.