Proliferation Of Cytokine-induced Killer Cells Research Articles

Combination therapy of irreversible electroporation and cytokine-induced killer cells for treating mice bearing panc02 pancreatic-cancer xenografts

The current study aimed to investigate the antitumor effects and potent mechanism of cytokine-induced killer (CIK) cells combined with irreversible electroporation (IRE) via Panc02 cell-bearing mouse model in vivo. CIK cells were isolated from the spleens of Panc02 pancreatic-cancer (PC) subcutaneous-xenograft model and the proportion of different lymphocytes was also determined. The antitumor effect of the combination of IRE and CIK cells in a PC subcutaneous-xenograft model was also investigated. The proportion of cells that were positive for CD3+CD8+ and the proportion of CD3+CD56+ cells were both significantly increased after 21 days of in vitro culture. Combined treatment of IRE and CIK cell significantly inhibited tumor growth and increased the survival rate of Panc02 cell–bearing mice. Furthermore, infiltration of lymphocytes into tumor tissue was significantly increased by this combination therapy compared with the untreated group or monotherapy group. In addition, IRE significantly enhanced the expression of chemokine receptors elicited by CIK cells. In conclusion, IRE combined with CIK cells showed superior antitumor efficacy in a PC xenograft model, which we attributed to the promotion of lymphocytic infiltration, as well as to upregulation of chemokine receptor expression and the regulators of CIK cell proliferation.

Compound Kushen Injection Promoted the Killing Effect of Cytokine-Induced Killer Cells Which Was Activated by Dendritic-Colon Cancer Stem Cell Fusion Cells on Colon Cancer Stem Cells

Colon cancer stem cells (cCSCs) are highly tumorigenic and resistant to traditional chemotherapeutic drugs. Therefore, they are an essential factor in colorectal cancer (CRC) metastasis and recurrence. Dendritic cells (DCs) could bind to the tumor cells and form the fusion cells (FCs). And these FCs could inhibit the development of malignant tumors. Furthermore, the cytokine induced killer (CIK) cells (CD3+ /CD56+ T lymphocytes) could also apply for the immunotherapy of cancer. And compound Kushen injection (CKI) is a traditional Chinese medicine (TCM) which has been used for the treatment of various tumors. However, whether the dendritic-colon cancer stem cell fusion cells (DC-cCSC FCs) could activate the CIK cells and kill the colon cancer stem cells is unknown. And whether the CKI could enhance the lethal effect is still unclear. In this study, we collected peripheral blood samples from healthy participants to acquire mononuclear cells and induced DC and CIK cells. Meanwhile, the CD44+ cells (cCSCs) were screened from SW480 cells. Next, the DC-cCSC FCs were established for the next experiments. At last, CCK-8 assays were performed to determine the effect of DC-cCSC FCs and CKI on the viability of cCSCs. We found that DC-cCSC FCs enhanced the proliferation of CIK cells and induce the CIK cells to secrete more IL-12. The DC-cCSC FCs enhanced the inhibitory effect of CIK cells on cCSCs. Furthermore, application of CKI enhanced the killing rates of DC-cCSC FCs and CIK cells on cCSCs. CIK cells activated by the DC-cCSC FCs had the lethal effect on the cCSCs. Furthermore, CKI enhanced this lethal effect of DC-cCSC FCs and CIK cells.

Increase in Efficacy of Checkpoint Inhibition by Cytokine-Induced-Killer Cells as a Combination Immunotherapy for Renal Cancer.

Cytokine-induced killer (CIK) cells are heterogeneous, major histocompatibility complex (MHC)-unrestricted T lymphocytes that have acquired the expression of several natural killer (NK) cell surface markers following the addition of interferon gamma (IFN-γ), OKT3 and interleukin-2 (IL-2). Treatment with CIK cells demonstrates a practical approach in cancer immunotherapy with limited, if any, graft versus host disease (GvHD) toxicity. CIK cells have been proposed and tested in many clinical trials in cancer patients by autologous, allogeneic or haploidentical administration. The possibility of combining them with specific monoclonal antibodies nivolumab and ipilimumab will further expand the possibility of their clinical utilization. Initially, phenotypic analysis was performed to explore CD3, CD4, CD56, PD-1 and CTLA-4 expression on CIK cells and PD-L1/PD-L2 expression on tumor cells. We further treated CIK cells with nivolumab and ipilimumab and measured the cytotoxicity of CIK cells cocultured to renal carcinoma cell lines, A-498 and Caki-2. We observed a significant decrease in viability of renal cell lines after treating with CIK cells (p < 0.0001) in comparison to untreated renal cell lines and anti-PD-1 or anti-CTLA-4 treatment had no remarkable effect on the viability of tumor cells. Using CCK-8, Precision Count Beads™ and Cell Trace™ violet proliferation assays, we proved significant increased proliferation of CIK cells in the presence of a combination of anti-PD-1 and anti-CTLA-4 antibodies compared to untreated CIK cells. The IFN-γ secretion increased significantly in the presence of A-498 and combinatorial blockade of PD-1 and CTLA-4 compared to nivolumab or ipilimumab monotreatment (p < 0.001). In conclusion, a combination of immune checkpoint inhibition with CIK cells augments cytotoxicity of CIK cells against renal cancer cells.

Stimulation of DC-CIK with PADI4 Protein Can Significantly Elevate the Therapeutic Efficiency in Esophageal Cancer.

Background PADI4 has extensive expression in many tumors. This study applied PADI4 as a tumor marker to stimulate DC- (dendritic cell-) CIK (cytokine-induced killer), an immunotherapy approach. Methods A PADI4 expression plasmid was transfected into EC-originating ECA-109 cells. PADI4 gene was also inserted into a prokaryotic expression vector to produce recombinant protein. Lysate from PADI4-overexpressing cells or the purified recombinant PADI4 protein was used to load DCs, and the cells were then coincubated with CIK cells. DC and CIK cell phenotypes were determined using flow cytometry. The proliferation and viability of CIK cells were analyzed using trypan blue staining. The cytotoxic effect of DC-CIK cells on cultured ECA-109 cells was determined using CCK8 assays. Tumor-bearing mice were prepared by injection of ECA-109 cells. DC-CIK cells stimulated with lysate from PADI4-overexpressing cells or the PADI4 recombinant protein were injected into the tumor-bearing mice. The tumor growth was measured with magnetic resonance imaging (MRI). Results Following incubation with lysate from PADI4-overexpressing cells, the ratio of CD40+ DCs increased by 17.5%. Induction of CIK cells with PADI4-stimulated DCs elevated the cell proliferation by 53.2% and the ability of CIK cells to kill ECA-109 cells by 12.1%. DC-CIK cells stimulated with lysate from PADI4-overexpressing cells suppressed tumor volume by 18.6% in the tumor-bearing mice. The recombinant PADI4 protein showed a similar effect on CIK cell proliferation and cytotoxicity as that of the lysate from PADI4-overexpressing cells. Furthermore, the recombinant protein elevated the ratio of CD40+ DCs by 111.8%, CD80+ DCs by 6.3%, CD83+ DCs by 30.8%, and CD86+ DCs by 7.8%. Induction of CIK cells with rPADI4-stimulated DCs elevated the cell proliferation by 50.3% and the ability of CIK cells to kill ECA-109 cells by 14.7% and suppressed tumor volume by 35.1% in the animal model. Conclusion This study demonstrates that stimulation of DC-CIK cells with PADI4 significantly suppressed tumor growth in tumor-bearing mice by promoting DC maturation, CIK cell proliferation, and cytotoxicity. PADI4 may be a potential tumor marker that could be used to improve the therapeutic efficiency of DC-CIK cells.

Lentiviral delivery of CTLA-4 shRNA improves the expansion of cytokine-induced killer cells and enhances cytotoxic activity in vitro.

Cytokine-induced killer (CIK) cells are in vitro-expanded cells harboring potent toxicity against tumor cells. Recently, it was identified that the cytotoxicity and proliferation of CIK cells are restricted by a prolonged CIK cell culture period. Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) serves a negative role in T cell activation and proliferation. This study aims to determine whether CTLA-4 expression is associated with the inhibition of CIK cells. CIK cells were generated from peripheral blood mononuclear cells (PBMCs), and CTLA-4 shRNA (shCTLA-4) lentivirus was applied to knockdown CTLA-4 expression in CIK cells. The proliferation of CIK cells was evaluated following shCTLA-4 lentiviral transduction, and the cytotoxicity of CIK cells was investigated using the CytoTox 96 Non-Radioactive Cytotoxicity assay. The expression of CTLA-4 in CIK cells was significantly increased, compared with that in PBMCs. The shCTLA-4 lentivirus efficiently knocked down the expression of CTLA-4 in CIK cells. The shCTLA-4 lentivirus transduction of CIK cells promoted the proliferation of CIK cells in vitro (3.18±0.19-fold vs. 2.42±0.29-fold). Furthermore, the cytotoxicity of shCTLA-4 lentivirus-transduced CIK cells was significantly improved when compared with that of control shRNA lentivirus-transduced CIK cells (54.5±2.13% vs. 30.5±1.67%). Thus, the suppression of CTLA-4 expression increases cytotoxicity and ex vivo expansion of CIK cells, which indicates a clinical significance for CTLA-4 blockade in CIK cell therapy.

Interleukin-15 enhances cytokine induced killer (CIK) cytotoxic potential against epithelial cancer cell lines via an innate pathway

CIK cells are a subset of effector lymphocytes endowed with a non-MHC restricted anti-tumor activity making them an appealing and promising cell population for adoptive immunotherapy. CIK are usually generated ex-vivo by initial priming with Interferon-γ (IFN-γ) and monoclonal antibody against CD3 (anti-CD3), followed by culture in medium containing Interleukin-2 (IL-2). Interleukin-15 (IL-15) shares with IL-2 similar biological functions and recently it has been reported to induce CIK with increased anti-leukemic potential.The aim of the study was to compare the killing efficacy of CIK generated by IL-2 alone or IL-2 and IL-15 toward tumor targets of different origins, leukemic cells and malignant cells from epithelial solid tumors. CIK bulk cultures were examined for cell proliferation, surface phenotype and cytotoxic potential against tumor cell lines K562, HL60, HeLa and MCF-7. The results showed that IL-15 is able to induce a selective expansion of CIK cells, but it is less effective in sustaining CIK cell proliferation compared to IL-2. Conversely, our data confirm and reinforce the feature of IL-15 to induce CIK cells with a potent cytotoxic activity mostly against tumor cells from epithelial solid malignancies via NKG2D-mediated mechanism.

Influence of autologous dendritic cells on cytokine-induced killer cell proliferation, cell phenotype and antitumor activity in vitro.

Dendritic cell (DCs) are essential antigen processing and presentation cells that play a key role in the immune response. In this study, DCs were co-cultured with cytokine-induced killer cells (DC-CIKs) in vitro to detect changes in cell proliferation, cell phenotype and cell cytotoxicity. The results revealed that the DCs were suitable for co-culture with CIKs at day 7, and that cell quantity of DC-CIKs was lower than that of CIKs until day 11, but it was significantly improved to 1.17-fold that of CIKs at day 13. Flow cytometry was used to detect the cell phenotype of CIKs and DC-CIKs. Compared with CIKs at day 13, the percentage of CD3+, CD3+CD4+, CD3+CD8+ and CD3+CD56+ T cells in DC-CIKs was significantly improved 1.02, 1.79, 1.26 and 2.44-fold, respectively. In addition, trypan blue staining analysis demonstrated that the cell viability of CIKs and DC-CIKs was 96% and 98%, respectively. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) analysis verified that CIK and DC-CIK cytotoxicity in Hela cells was 58% and 80%, respectively, with a significant difference. Taken together, our results indicate that the cell proliferation, cell phenotype and antitumor activity of CIKs were all enhanced following co-culture with DCs in vitro. These results are likely to be useful for DC-CIK application in antitumor therapies.

Anti-CD20 antibody induces the improvement of cytokine-induced killer cell activity via the STAT and MAPK/ERK signaling pathways.

There is a current requirement for novel therapeutic strategies for the treatment of hematopoietic tumors. Residual tumor cells are the main origin of tumor relapse. The aim of this study was to eliminate the residual tumor cells of hematopoietic tumors. Cytokine-induced killer (CIK) cells are used in immunotherapy to deplete the residual cells. However, it is necessary to increase the antitumor activity and clinical applicability of CIK cells. The present study investigated the antitumor activity of CIK cells to the SU-DHL2 human B-cell lymphoma and K562 human chronic myelogenous leukemia cell lines. CD3+CD56+ cells from healthy donors were expanded in culture with cytokines and anti-CD20 monoclonal antibody (mAb; rituximab) to generate CIK cells. A preliminary investigation of their mechanism was then performed. The increase in the cytotoxicity of the CIK cells induced by the anti-CD20 mAb was associated with an increase in the expression of cytotoxic factors. The expression of components of the signal transducer and activator of transcription (STAT) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathways was found to increase. Upregulation of the expression of STAT1, STAT3 and STAT5 is important as these co-stimulatory molecules enhance T-cell proliferation. Activation of the MAPK signaling pathway is a possible mechanism for the anti-apoptosis effect on the proliferation of CIK cells. In conclusion, anti-CD20 mAb may play an important role in the improvement of CIK-mediated cytotoxicity to tumor cells. These observations may aid in the improvement of the effects of immunotherapy in depleting the residual cells of hematopoietic tumors. Thus, the use of CIK cells cultured with anti-CD20 mAb could be a novel therapeutic strategy for the depletion of chemotherapy-resistant or residual cells in anaplastic large and B-cell lymphoma.

Investigation of proliferation and cytotoxicity capacity of cytokine-induced killer cells: Omics strategy

C trials of Cytokine-Induced Killer (CIK) cells based immunotherapy against cancer are widely performed in China. However, the mechanism of CIK cell proliferation and acquisition of cytolytic function against tumor have not been well elucidated yet. We compared the proliferation and tumor toxic capacity between CIKIL-2 and CIKIL-15. By employing microarray, we analyzed miRNA expression profiles of PBMCs, CIKIL-2 and CIKIL-15. Moreover, RNA-seq was performed to identify differentially expressed genes between CIKIL-2 and CIKIL-15. The results indicated that CIKIL-15 showed improved cell proliferation capacity compared to CIKIL-2. However, CIKIL-2 has exhibited greater tumor cytotoxic effect than CIKIL-15. Bioinformatic analysis indicated that miR-143-3p/miR-145-5p was miRNA cluster which may positively regulated cell proliferation. In contrast, miR-340-5p/miR340-3p cluster may negatively regulate cell proliferation via induction apoptosis, which may cause decreased cell proliferation capacity of CIKIL-2. Importantly, we found that repressed miR-193a-5p may regulate the expressions of inhibitory receptor KLRD1 which may restrict cytotoxic function of CIK. Employing deep sequencing, a total of 374 differentially expressed genes (DEGs) were identified. Among DEGs in CIKIL-15, Wnt signaling and cell adhesion were significant GO terms and pathways which related with their functions. In CIKIL-2, type I interferon signaling and cytokine-cytokine receptor interaction were significant GO terms and pathways. We found that inhibitory signal from interaction between CTLA4 and CD80 may be responsible for the weak proliferation capacity of CIKIL-2. Our findings have provided new insights into mechanisms of CIK cells production and tumor cytotoxic function.

Effects of different stimulatory factors on functions of CIK cells

This study was aimed to investigate the effects of different stimulatory factors on proliferation and function of cytokine induced killer (CIK) cells. Peripheral blood mononuclear cells (PBMNC) were separated by Ficoll-Hypacue gradient. According to supplement of different stimulatory factors (CD28 mAb, IL-15 and IL-21), the experiment was divided into five groups:control group (CIK), CB28+IL-15+IL-21 group, IL-15+IL-21 group, CD28+IL-15 group and CD28+IL-21 group. Effects of different stimulatory factors on the proliferation of CIK cells were assayed by an automated hematology analyzer. Changes of granzyme B,perforin and CD107a were detected by flow cytometry. IL-10, IL-12, INF-γ and TNF-α were quantified by ELISA. Cytotoxicities on lung cancer cell line A549, breast adenocarcinoma cell line MFC-7 and human melanoma cell line HME1 were examined by lactate dehydrogenase release method. The results showed that there were significant differences among different groups. The highest proliferation index on days 10 was observed in group CD28mAb, IL-15 and IL-21(255.3 ± 6.3), which was higher than control group, IL-21+IL-15 group and CD28 mAb+IL-21 group (166.6 ± 13.5, 199.4 ± 15.0 and 228.8 ± 16.6) (P < 0.05). The expression of perforin in CD28 mAb+IL-15 group was higher than the other groups. The expression of perforin,GranB and CD107a of costimulatory groups was higher than control group. The cytotoxicities of CD28 mAb+IL-15 group on A549, MFC-7 and HME1 cells (82.2%, 59.3% and 70.6%) were much higher than that of control group (60.9%, 49.6% and 48.4%) (P < 0.05). The highest IFN-γsecretion was found in CD28 mAb, IL-15 and IL-21 groups. It is concluded that there are significant difference of proliferative capacity, cytokine secretion and cytotoxicity after being activated by different stimulatory factors. Adding corresponding stimulatory factors into the culture system displays a great value for target cells culture.

Multiple Cytotoxic Factors and JAK/STAT Pathways Are Involved in the Enhanced Antitumor Function of CIK Cells Induced by IL-21

Abstract 1059Adoptive transfer of activated T and NK cells has had significant clinical benefits in certain tumor models. Cytokine induced killer (CIK) cells are a group of cells that possess both T and NK cell like recognition of target cells. These cells are generated after extensive ex vivo manipulation of PBMCs. Maintenance of not only CIK cells but other activated effector T and NK cells in culture is vital for their effective transfer and development following adoptive immunotherapy. IL-21 is the newest member of the common γ chain family which has been shown to increase cytotoxic factors and cytokine secretion in immune cells without over stimulation. Such qualities make IL-21 a suitable agent in immunotherapy of tumors. IL-21 has shown effective antitumor function and is currently going clinical trials for tumors such as renal cell carcinoma, melanoma and lymphoma. Our previous experiment showed that like in T cells and NK cells, IL-21 significantly improves the cytotoxicity of CIK cell on K562 cells and primary leukemic cells from patients. Although proliferation of cells in a CIK cell pool was not observed we found that it helped maintain and grow the CD3+ and CD56+ phenotype. Our present experiment aims to explain the mechanism through which IL-21 promotes CIK cells survival and cell cytotoxicity.In our experiment, blood from healthy donors was collected and PBMCs were transformed into CIK cells following 14 days of culture using appropriate methods. The cells were then stimulated with IL-21 for a defined period of time and subjected to MTT assays to measure cellular viability and cytotoxicity to K562 cells. To elucidate the mechanism of action of IL-21, CIK cells were checked for the level of mRNA expression of perforin, Granzyme B, FasL, INF-γ, TNF-α,Granzyme A,NKG2D, TNF-β using RT-PCR. Furthermore the expression of significantly important cytotoxic factors and cytokines was measured through flow cytometry and ELISA. Western blot was performed to check the involvement of JAK/STAT pathway following stimulation.We found that IL-21 doesn’t enhance in vitro proliferation of CIK cells, but does increase the number of cells expressing the CD3+/CD56+ phenotype. IL-21 can also significantly increase the cytotoxic potential of CIK cells to K562 cells. It does so with significantly increased production of perforin which increased almost 2 folds from (0.5592±0.1457) to (0.9831±0.1265); Granzyme B also by almost 2 folds from (0.4084±0.1589) to (0.7319±0.1639) and FasL which increased by almost 2 folds from (0.4015±0.2842) to (0.7381±0.2568). Increase in secretion of cytokines such as INF-γ was observed from (25.8±6.1)ng/L to (56.0±2.3)ng/L; and TNF-α from (5.64±0.61)ug/L to (15.14±0.93)ug/L while no significant difference was observed in the expression of Granzyme A,TNF-β and NKG2D. Measurement of IL-21R receptor on CIK cell surface following IL-21 stimulation caused a more than two folds increase in expression of IL-21R from 1.88% to 4.25%. We further affirm that JAK/STAT is actively involved in IL-21 signalling. STAT3 and STAT5b could be potential signalling mechanisms taking part in IL-21 enhanced cytotoxic potential of CIK cells.Using this information we have concluded that increased expression of perforin, Granzyme B, FasL, IFN-γ and TNF-α plays a significant role in IL-21 enhanced cytotoxic potential of CIK cells and STAT-3 and STAT-5b signaling pathway are involved in the processes. Our data indicate that IL-21 is a potent enhancer of antitumor function of CIK cells. As CIK cells and IL-21 have both been shown to increase patient survival or tumor free periods in certain hematological malignancies using them in conjunction might be therapeutically more beneficial. Disclosures:No relevant conflicts of interest to declare.

English

This research objective was to exploit a novel method for measuring the proliferation, cytotoxicity of&nbsp;cytokine-induced killer&nbsp;(CIK)&nbsp;cells using carboxyfluorescein succinimidyl ester/proliferation index&nbsp;(CFSE/PI)&nbsp;and flow cytometric assay. As cells divide, CFSE is apportioned equally between the two daughter cells, leading to a characteristic flow cytometric profile where a number of peaks of progressively halving CFSE fluorescence intensity&nbsp;were&nbsp;observed. The test principle of cytotoxicity is based on target cell labeling with CFSE and subsequent DNA-labeling with PI for the identification of target cells with compromised cell membranes. Results of CFSE&nbsp;fluorescence&nbsp;profile&nbsp;of the entire cell population&nbsp;showed that these cells underwent up to 6 divisions after 21 days. The percentage of total dividing cell population was 97.12%, of which 17.28% cells went through 6 rounds and 6.84% cells entered the seventh generation. The cytotoxicity of CIK cells showed a significant and positive correlation with effector: target (E:T) ratio ranging from 50:1 to 6.25:1. CFSE labeling combined with flow cytometry can therefore be used to monitor the proliferation of CIK cells. Moreover, it presents an advantageous method to measure cytotoxicity of CIK cells by avoiding radioactive substance, increasing sensitivity at low E:T ratio, analyzing on a cell-to-cell basis and allowing for long-term incubation. &nbsp; Key words:&nbsp;Flow cytometry, CFSE,&nbsp;cytokine-induced killer cell, proliferation, cytotoxicity.

Effects of inducible co-stimulator gene on the cytotoxic activity of cytokine-induced killer cells against cholangiocarcinoma cells

Objective To explore the effects of inducible co-stimulator (ICOS) gene on the cytotoxic activity of cytokine-induced killer (CIK) cells against cholangiocarcinoma cells. Methods CIK-ICOS cells were obtained by stable transfecting ICOS genes into CIK cells through the adenovirus vector whereas untransfected and EGFP-transfected CIK cells were treated as controls. The proliferation and apoptosis of different CIK cells, as well as their cytotoxicity against cholangiocarcinoma cells in the three groups were detected. The expressions of IFN-T, IL-2 and TNF-α in the supernatant of different CIK cells were measured by ELISA. SCID mice with cholangiocarcinoma were randomly divided into CIK group, CIK-EGFP group, CIK-ICOS group and normal saline group. The cytotoxic activity of CIK-ICOS cells against cholangiocarcinoma cells in vivo was observed. Results CIK-ICOS cells displayed better proliferation than CIK cells and CIK-EGFP cells. At day 20 and 23 of culture, the apoptosis rate of CIK-ICOS cells was 0.69% and 0.89%, respectively, while that of the CIK cells was 2.90% and 4.92%. The cytotoxic effect of CIK-ICOS cells at different E: T ratio against cholangiocarcinoma cells was significantly stronger than that of CIK cells and CIK-EGFP cells (F=13.37, 6.46, 25.51, P<0.05). The concentration of IFN-γ in CIK-ICOS cultured supernatant was (49.50±4.73)μg/L, which was significantly higher than that in the cultured supernatant of CIK cells [(30.53±3.73)μg/L] and CIK-EGFP cells [(30.12±2.64)μg/L](F=38.89, P<0.05). The growth of cholangiocarcinoma was significantly slower in CIK-ICOS group than that in CIK group and CIK-EGFP group, whereas the necrosis area of tumor was larger and the CIK cells in CIK-ICOS group was more than those in the other two groups. Conclusions CIK cells had the function of killing cholangiocarcinoma cells in vitro and in vivo. After ICOS genes were transfected into CIK cells, the survival time of CIK cells in vitro was prolonged and the proliferation of CIK cells was enhanced, as well as the secretion of IFN-γ was increased so that the cytotoxicity of CIK cells against cholangiocarcinoma cells in vitro and in vivo was enhanced. Key words: Cholangiocarcinoma; Inducible co-stimulator; Cytokine-induced killer cells

The apoptotic and proliferative fate of cytokine-induced killer cells after redirection to tumor cells with bispecific Ab

Cytokine-induced killer (CIK) cells are ex vivo expanded T cells with co-expression of CD3 and CD56 and NK activity. They have recently been evaluated in a phase I/II clinical trial against malignant lymphoma. Bispecific Ab (bsAb) redirect CIK cells to tumor targets, thus enhancing their cytotoxicity. While bsAb may improve T-cell mediated anti-tumor activity, little is known about the fate of effector cells upon redirection to tumor targets using a bsAb. Using ex vivo-activated CIK cells, Her2/neu expressing breast and ovarian cell lines and a F(ab')2 Her2/neu x CD3 bsAb, we investigated the anti-tumor activity and the proliferative and apoptotic outcome of CIK cells. When redirected to tumor targets with bsAb, there was a significant increase in anti-tumor activity as well as an increase in both CIK cell proliferation and apoptosis. The addition of agonistic Ab against CD28 did not significantly increase proliferation or apoptosis of CIK cells redirected to CD80- and CD86- tumor targets. To attempt to reduce T-cell apoptosis, we incubated CIK cells in the presence of the pan-caspase inhibitor z-VAD-fmk, which led to a partial reduction in T-cell apoptosis without increasing cellular cytotoxicity. bsAb are effective in redirecting activated T cells to tumor targets and such redirection leads to both T-cell proliferation and apoptosis that are not altered by co-stimulation through CD28. Effector cell apoptosis can be reduced by using a caspase inhibitor but this does not increase CIK cell cytotoxicity.

Effects of Ganoderma lucidum polysaccharides on proliferation and cytotoxicity of cytokine-induced killer cells

To study the effects (and the mechanisms thereof) of Ganoderma lucidum polysaccharides (Gl-PS) on the proliferation and the anti-tumor activity of cytokine-induced killer (CIK) cells, and to make use of CIK cells as a means to investigate the interactions between Gl-PS and cytokines. CIK cells were prepared by using the standard protocol as a positive control. Experimental groups also underwent the standard protocol, except that Gl-PS (400 mg/L or 100 mg/L) was added and the dose of anti-CD3 and interleukin-2 they received was reduced by 50% and 75%, respectively. For negative controls, Gl-PS in the experimental protocol was replaced with soluble starch or methylcellulose (400 mg/L or 100 mg/L). CIK cell proliferation, cytotoxicity, and phenotype were determined by using the Trypan blue exclusion method, MTT assay, and flow cytometry. By synergizing cytokines, Gl-PS (400 mg/L or 100 mg/L) could decrease the amount of cytokine in lymphokine activated killer (LAK) cells and CIK cells culture, but had no significant effect on the proliferation, cytotoxicity, or phenotype of LAK cells, or CIK cells induced by cytokines at higher doses alone, in which CIK cells expanded about 80-fold and the main effectors, CD3+NK1.1+ cells, expanded by more than 15%. The cytotoxicity of CIK cells in experimental groups was 79.3%+/-4.7%, 76.9%+/-6.8% versus the positive control 80.7%+/-6.8% against P815 (P>0.05) and 88.9%+/-5.5%, 84.7%+/-7.9% versus the positive control 89.8%+/-4.5% against YAC-1 (P>0.05). The activity of Gl-PS could mostly be blocked by anti-CR3. Gl-PS was shown to be a promising biological response modifier and immune potentiator. The effect of Gl-PS on CIK cells is possibly mediated primarily through complement receptor type 3.