Effect Of Dendritic Cells Research Articles

Experimental study of transfecting adenovirus carrying G250 antigen gene to dendritic cells and to activate immune effector cells in kidney cancer treatment

Objective To investigate T cell-mediated effects of dendritic cells(DC)transfected with kidney associated antigen G250 gene using adenovirus(Ad)as vector in the treatment of kidney cancer. Methods Peripheral blood mononuclear cells(PBMC)were isolated by standard FicollPaque density gradient centrifugation of heparinized blood obtained from healthy donors.After removal of the nonadherent ceils,the adherent cells were divided into gene transfer group,protein pulsed group and control group.The gene transfer group was infected with Ad/G250 virus;the protein pulsed group was added with G250 protein; the control group was added with PBS.The DCs were cultured and proliferated in vitro using recombinant human granulocyte macrophage colony stimulating factor and inlerleukin-4.The autologous T cells were added into the 3 DC groups(responders:dendritics,20:1).After 5 d co-culture,3 eytotoxic T lymphocyte(CTL)groups were collected.TheG250 mRNA expression was detected in transduced DCs using RT-PCR.The G250 protein translation products and cell surface marker of DCs were analyzed by flow cytometry.The specific cytolytic activities of CTL to different target cells(renal carcinoma 786-0 cell line and lung cancer A549 cell line)were assessed by MTT method. Results Ad/G250 transfected DC successfully and the G250 expression was confirmed by RT-PCR. The expression levels of CD_(80), CD_(83). HLA-DR and CD_(86) in the Ad/G250 group were higher than those in the other 2 groups. The cytotoxicity to 786-0 of T lymphocytes activated by Ad/G250 transfecting DCs(83. 4±2. 8)% was greater than those of T lymphocytes in the protein pulsed group(79. 6±2. 4)% and control group(77. 3±2. 1)%. There were no significant differences of the cytotyxicities to A549 among the 3 cytotoxic T lymphocyte groups(F=0. 373.P=0.693). Conclusions Ad-loading DCs may be useful for immunotherapeutic protocols against self-antigens for the kidney cancer. Key words: Dendritic cells; Carcinoma, renal cell; Adenoviridae; T-lymphocytes, cytotoxic

1-MT enhanced potency of dendritic cells pulsed with tumor cell lysate by downregulation of CD4 ~+ CD25~+ treg

Objective To determine whether 1-methyl-tryptophan (1-MT, an IDO inhibitor) might reduce CD4~+ CD25~+ Treg and improve the anti-tumor effects of dendritic cells pulsed with tumor cell lysate in the murine pancreas adenocarcinoma model. Methods Pan02 cell line was injected into syngeneic C57BL/6 mice. 1-MT was administered to pancreas adenocarcinoma mice and its effect on the prevalence of regulatory T cells (Treg) in tumor draining lymph nodes (TDLNs) and spleen was investigated. The prevalence of Treg in the TDLNs and tumor spleen (TS) was detected by using flow cytometry. The expression level of Foxp3 mRNA was detected in the spleen and TDLN by real-time PCR. To prepare the DC vaccine,dendritic cells were pulsed with tumor cell lysate. This DC vaccine, as a single agent or in combination with 1-MT, was administered to pancreas adenocarcinoma mice. The anti-tumor effects in different treatment were deter mined by regular observation of tumor development. Results There was statistically significant difference in the percentage of CD4~+ CD25~+ T lyraphocytessignificant between 1-MT-treated group [TDLNs (16.01 ± 2.21)% and TS (13. 11 ± 1. 93)%] than PBS control group [TDLNs (25. 00 ± 2. 16)% and TS (22.14 ±2.33)%] (P<0.05,P<0.01). In 1-MT-treated group,the Foxp3 expression was significantly lower in TDLN and TS than in control LN and spleen. Furthemore,in 1-MT + DC vaccine-treated group,the tumor growth rate was significantly slower than in groups of DC vaccine, 1-MT and PBS (the tumor volume was (789.0 ±111.0), (1768.0 ±251. 3), (1854.0 ±192. 1),(1899.0 ±201.2) mmJ at the 36th day af ter tumor challenge, respectively (P < 0. 01). Conclusion 1-MT can enhance anti-tumor effects of den dritic cells pulsed with tumor cell lysate by downregulating the expression of CD4~+ CD25~+ Treg. Key words: Pancreas adenocarcinoma; Dendritic cells; Vaccine

Treatment of established colon carcinoma-bearing mice by dendritic cells pulsed with lysates of heat-treated tumor cells

To investigate the therapeutic effect of dendritic cells pulsed with lysates of heat-treated CT26 colon carcinoma cells. Bone marrow-derived DCs were pulsed with lysates of heat-treated tumor cells and were used to immunize BALB/c mice with established colon carcinoma. Cytotoxic T lymphocyte (CTL) response was detected. The therapeutic effect induced by DCs was observed by tumor weight and survival time. DCs pulsed with lysates of heat-treated tumor cells markedly induced specific cytotoxic activity of CTLs. Tumor growth in the immunized BALB/c mice was significantly inhibited and the survival time of the tumor-bearing mice was prolonged. DCs pulsed with lysates of heat-treated tumor cells have an observable therapeutic effect on established colon carcinoma-bearing mice.

Effects of dendritic cell vaccines on hematogenous micrometastasis of bladder cancer carrying for PBL-SCID mice

To study the effect of dendritic cells loaded with whole tumor antigen on hematogenous micrometastasis of bladder cancer model in hu-PBL-SCID mice. T24-3 cell subset was selected from human bladder transitional cell carcinoma T24 cell line by Boyden chamber system. The SCID mice intraperitoneally injected with 4 × 107 hu-PBL and subcutaneously injected with 3 × 106 T24-3 cells were named hu-PBL-T24-3-SCID model. Human IgG level in the blood plasma of mice was detected by ELISA, and human CD3+, CD4+, CD8+ T cells in blood and spleen cells of mice were detected by FCM analysis for human immune reconstruction study. Human CK20 mRNA expression in mice peripheral blood was detected by RT-PCR to investigate metastasis of tumor cells. The PBMCs were isolated from human peripheral blood, and were induced into DCs by co-culture with rhGM-CSF and rhIL-4 in vitro. The DC vaccines were produced by co-culturing with whole tumor antigen which was purified through freezing and melting T24-3 cell subset. After T24-3 cells injected into SCID mice for 5 weeks, the mice were treated with DC vaccines. All mice were initially treated at 5th week. The expression of CK20 mRNA in peripheral blood of DC vaccines treated mice was the lowest. There was 2 mice showing CK20 mRNA expression and 3 mice with metastasis tumor in PBS group. MMP-7 mRNA expression in tumor tissues of DC vaccines treated mice was statistically lower than that of PBS group (P < 0.01). DC vaccines have a good effect on hu-PBL-SCID mice bladder cancer model by reducing hematogenous micrometastasis.

RETRACTED: Immunosuppressive networks in the tumour environment and their effect in dendritic cells

The failure of the immune system to provide protection against tumour cells is an important immunological problem. It is now evident that inadequate function of the host immune system is one of the main mechanisms by which tumours escape from immune control, as well as an important factor that limits the success of cancer immunotherapy. In recent years, it has become increasingly clear that defects in dendritic cells have a crucial role in non-responsiveness to tumours. This article focuses on the functional consequences and recently described mechanisms of the dendritic-cell defects in cancer.

Cancer Immunotherapy UsingIn vitroGenetically Modified Targeted Dendritic Cells

Modest clinical outcomes of dendritic cell (DC) vaccine trials call for novel strategies. In this study, we have created a chimeric CD40 molecule that incorporates a single chain Fv (scFv) molecule specific for human ErbB2 antigen and fusing to the membrane spanning and cytosolic domains of murine CD40. After adenoviral transfer to bone marrow-derived DC, this chimeric receptor (CR) induced nuclear factor-kappaB (NF-kappaB)-dependent DC activation and effector function when cultured with immobilized ErbB2 protein or ErbB2-positive tumor cells in vitro. In vivo migration assays showed that approximately 40% injected CR-modified DC (scFv-CD40-DC) effectively migrated to ErbB2-positive tumors, where they were activated after ErbB2 antigen stimulation, and sequentially homed into the draining lymph nodes. In murine ErbB2-positive D2F2/E2 breast tumor (BALB/c) and EL4/E2 thymoma (C57BL/6) models, i.v. injection of 1 x 10(6) scFv-CD40-DC significantly inhibited tumor growth and cured established tumors. Importantly, the cured mice treated by injection of scFv-CD40-DC were effective in preventing both ErbB2-positive and parental ErbB2-negative tumor rechallenge. Analysis of the underlying mechanism revealed that i.v. infusion of scFv-CD40-DC elicited tumor-specific CTL responses, and the transfer of CTLs from scFv-CD40-DC-treated mice protected naive mice against a subsequent tumor challenge. These results support the concept that genetic modification of DC with tumor-associated antigen-specific CD40 chimeric receptor might be a useful strategy for treatment of human cancers.

CADA, a Potential Anti-HIV Microbicide that Specifically Targets the Cellular CD4 Receptor

The cyclotriazadisulfonamide (CADA) compounds are a new class of specific CD4-targeted HIV entry inhibitors. The in vitro anti-HIV activity of CADA was shown to correlate with its ability to specifically downmodulate cell surface expression of the CD4 receptor in human cells. Here, we evaluated its potential as an anti-HIV microbicide. CADA exerted a clear CD4 receptor downregulating effect in dendritic cells (DC) and subsequently inhibited HIV-1(BaL) replication in DC/T cell co-cultures. The compound proved to be active against a variety of clinical isolates belonging to the HIV-1 subtypes A, B, C, D, F, G, H, AE and O. Furthermore, it prevented human T cells from being infected with the laboratory-adapted strains X4 HIV-1(NL4.3) and R5 SIV(mac251). Flow cytometric analysis demonstrated a significant and dose-dependent downregulation of CD4 on macaque PBMCs. In addition, the compound exerted a marked anti-SIV(mac251) activity in these cells from simian origin. The combination of CADA with cellulose acetate phthalate (CAP) resulted in a synergistic inhibition of HIV-1 and SIV infection. Finally, gel formulated CADA proved to preserve the CD4 downmodulating and antiviral activity of this compound when formulated as a microbicide gel. Thus, our data suggest that CADA may have potential as a broad-spectrum anti-HIV microbicide drug candidate. The preservation of the activity of gel formulated CADA will make it now feasible for testing this unique entry inhibitor in non-human primates, not only as a single drug but also in a synergistic conjunction with other anti-HIV compounds.

Effect of dendritic cells loaded with HBsAg on the differentiation of HBsAg-specific T helper 1 cells in patients with chronic hepatitis B

Effect of dendritic cells loaded with HBsAg on the differentiation of HBsAg-specific T helper 1 cells in patients with chronic hepatitis B

The effect of dendritic cells on the retinal cell transplantation

The potential of bone marrow cell-derived immature dendritic cells (myeloid iDCs) in modulating the efficacy of retinal cell transplantation therapy was investigated. (1) In vitro, myeloid iDCs but not BMCs enhanced the survival and proliferation of embryonic retinal cells, and the expression of various neurotrophic factors by myeloid iDCs was confirmed with RT-PCR. (2) In subretinal transplantation, neonatal retinal cells co-transplanted with myeloid iDCs showed higher survival rate compared to those transplanted without myeloid iDCs. (3) CD8 T-cells reactive against donor retinal cells were significantly increased in the mice with transplantation of retinal cells alone. These results suggested the beneficial effects of the use of myeloid iDCs in retinal cell transplantation therapy.

TGF-beta insensitive dendritic cells: an efficient vaccine for murine prostate cancer.

Dendritic cells (DCs) are highly potent initiators of the immune response, but DC effector functions are often inhibited by immunosuppressants such as transforming growth factor beta (TGF-beta). The present study was conducted to develop a treatment strategy for prostate cancer using a TGF-beta-insensitive DC vaccine. Tumor lysate-pulsed DCs were rendered TGF-beta insensitive by dominant-negative TGF-beta type II receptor (TbetaRIIDN), leading to the blockade of TGF-beta signals to members of the Smad family, which are the principal cytoplasmic intermediates involved in the transduction of signals from TGF-beta receptors to the nucleus. Expression of TbetaRIIDN did not affect the phenotype of transduced DCs. Phosphorylated Smad-2 was undetectable and expression of surface co-stimulatory molecules (CD80/CD86) were upregulated in TbetaRIIDN DCs after antigen and TGF-beta1 stimulation. Vaccination of C57BL/6 tumor-bearing mice with the TbetaRIIDN DC vaccine induced potent tumor-specific cytotoxic T lymphocyte responses against TRAMP-C2 tumors, increased serum IFN-gamma and IL-12 level, inhibited tumor growth and increased mouse survival. Furthermore, complete tumor regression occurred in two vaccinated mice. These results demonstrate that blocking TGF-beta signals in DC enhances the efficacy of DC-based vaccines.

Potential Side Effects of Dendritic Cells Pulsed with Allogenic Melanoma Cell Lysate in Mice

An attempt has been made to investigate the toxicity of cancer immunotherapy based on the dendritic cells pulsed with lysate of allogenic melanoma cell, DM401. Dendritic cells pulsed with lysate of clone M3 were subcutaneously administered once a week eight times to C57BL/6 mice at 0, 2.5, 5, and 10 x 10(7) cells/kg. No changes attributable to the administration were observed in clinical signs and food and water consumption. The administration induced slight increases in body weights, white blood cells, total protein, total cholesterol, triglyceride, phospholipids, and absolute spleen weights, but a slight decrease in albumin/globulin ratio. Microscopic examinations revealed the infiltration of inflammatory cells in the lung, mainly in the pulmonary arteriole, in which the tunica media thickened, and in the pulmonary alveoli and alveolar space. Thickened tunica media of pulmonary arteriole was observed in both males and females at all selected doses. In addition, the subcutis at the test substance-application site showed inflammation and fibrosis. In conclusion, lung is a target organ of DM401, and most of the changes including the findings in lung are considered as the immunomodulatory functions of dendritic cells.

Human platelets target dendritic cell differentiation and production of proinflammatory cytokines

Dendritic cells (DCs) are the most potent antigen-presenting cells that initiate and regulate immune responses. They are unique in their feature to produce bioactive interleukin (IL)-12, a major proinflammatory cytokine connecting innate and adaptive immunity. Platelets (PLTs) are highly reactive components of the circulatory system with fundamental importance in hemostasis and innate immunity. Recently, immunomodulatory capacities of single specific human PLT-derived products on DC effector functions were identified. To improve the understanding of PLT-DC interactions, this study investigates the influence of intact resting and activated PLTs on DC phenotype and key functions. Magnetic beads sorted CD14+ cells were expanded in the presence and absence of resting or activated PLTs. DC differentiation, maturation, allostimulatority capacity, antigen uptake, and cytokine profile were estimated to control group. Activated PLTs potently impaired DC differentiation according to CD1a expression (mean reduction, 62%; p < 0.05). Production of IL-12p70 and tumor necrosis factor-alpha was reduced in the presence of resting (mean reduction, 46 and 55%, respectively; p < 0.05) as well as activated PLTs (mean reduction, 63 and 49%, respectively; p < 0.05). In contrast to the suppression of proinflammatory cytokines, activated PLTs increased production of the immunoregulatory cytokine IL-10 by DCs (mean increase, 52%; p < 0.05). DC allostimulatority capacity, antigen uptake, and phenotypic maturation remained unaffected. It is proposed that intact PLTs connect immunity and hemostasis by interfering with DC differentiation and cytokine production. This interference might be of importance in clinical settings, such as DC therapy and PLT transfusions.

Nitric Oxide Sensitizes Tumor Cells to Dendritic Cell–Mediated Apoptosis, Uptake, and Cross-Presentation

Dendritic cells are professional antigen-presenting cells associated with efficient antigen processing and presentation to T cells. However, recent evidence also suggests that dendritic cells may mediate direct tumoricidal functions. In this study, we investigated the mechanism by which murine dendritic cells mediate the apoptotic death of murine lymphoma cell lines, and whether dendritic cell effector function could be enhanced by preconditioning tumor cells with the protein phosphatase inhibitor nitric oxide (NO) by altering the balance of proapoptotic/antiapoptotic proteins in the treated cells. We observed that NO donor compound sensitized lymphomas to dendritic cell-mediated cytotoxicity in vitro. Both immature and spontaneously matured bone marrow-derived dendritic cells (SM-DC) were capable of inducing tumor cell apoptosis, with SM-DCs serving as comparatively better killers. Fas ligand (FasL)-Fas engagement proved important in this activity because elevated expression of membrane-bound FasL was detected on SM-DCs, and dendritic cells derived from FasL-deficient mice were less capable of killing NO-sensitized tumor cells than wild-type dendritic cells. As FasL-deficient dendritic cells were still capable of mediating a residual degree of tumor killing, this suggests that FasL-independent mechanisms of apoptosis are also involved in dendritic cell-mediated tumor killing. Because NO-treated tumor cells displayed a preferential loss of survivin protein expression via a proteasome-dependent pathway, enhanced tumor sensitivity to dendritic cell-mediated killing may be associated with the accelerated turnover of this critical antiapoptotic gene product. Importantly, NO-treated tumor cells were also engulfed more readily than control tumor cells and this resulted in enhanced cross-presentation of tumor-associated antigens to specific T cells in vitro.

Milk‐Derived GM3 and GD3 Differentially Inhibit Dendritic Cell Maturation and Effector Functionalities

Gangliosides are complex glycosphingolipids, which exert immune-modulating effects on various cell types. Ganglioside GD(3) and GM(3) are the predominant gangliosides of human breast milk but during the early phase of lactation, the content of GD(3) decreases while GM(3) increases. The biological value of gangliosides in breast milk has yet to be elucidated but when milk is ingested, dietary gangliosides might conceptually affect immune cells, such as dendritic cells (DCs). In this study, we address the in vitro effect of GD(3) and GM(3) on DC effector functionalities. Treatment of bone marrow-derived DCs with GD(3) before lipopolysaccharide-induced maturation decreased the production of interleukin-6 (IL-6), IL-10, IL-12 and tumor necrosis factor-alpha as well as reduced the alloreactivity in mixed leucocyte reaction (MLR). In contrast, only IL-10 and IL-12 productions were significantly inhibited by GM(3,) and the potency of DCs to activate CD4(+) cells in MLR was unaffected by GM(3). However, both gangliosides suppressed expression of CD40, CD80, CD86 and major histocompatibility complex class II on DCs. Because GD(3) overall inhibits DC functionalities more than GM(3), the immune modulating effect of the ganglioside fraction of breast milk might be more prominent in the commencement of lactation during which the milk contains the most GD(3).

4-Tertiary Butyl Phenol Exposure Sensitizes Human Melanocytes to Dendritic Cell-Mediated Killing: Relevance to Vitiligo

The trigger initiating an autoimmune response against melanocytes in vitiligo remains unclear. Patients frequently experience stress to the skin prior to depigmentation. 4-tertiary butyl phenol (4-TBP) was used as a model compound to study the effects of stress on melanocytes. Heat shock protein (HSP)70 generated and secreted in response to 4-TBP was quantified. The protective potential of stress proteins generated following 4-TBP exposure was examined. It was studied whether HSP70 favors dendritic cell (DC) effector functions as well. Melanocytes were more sensitive to 4-TBP than fibroblasts, and HSP70 generated in response to 4-TBP exposure was partially released into the medium by immortalized vitiligo melanocyte cell line PIG3V. Stress protein HSP70 in turn induced membrane tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expression and activation of DC effector functions towards stressed melanocytes. Melanocytes exposed to 4-TBP demonstrated elevated TRAIL death receptor expression. DC effector functions were partially inhibited by blocking antibodies to TRAIL. TRAIL expression and infiltration by CD11c+ cells was abundant in perilesional vitiligo skin. Stressed melanocytes may mediate DC activation through release of HSP70, and DC effector functions appear to play a previously unappreciated role in progressive vitiligo.

445 Differential effects of dendritic cells versus monocytes on CD4+ and CD8+ T cell induction by HCV-derived lipopeptide LP20-44

445 Differential effects of dendritic cells versus monocytes on CD4+ and CD8+ T cell induction by HCV-derived lipopeptide LP20-44

Study of immunological effect of dendritic cell transfected with survivin gene on the specific anti-alimentary tract tumor

To investigate the effects of dendritic cells (DCs) transfected with survivin gene, and to observe the effective and specific anti-tumor immunological effect induced by modified DC in vitro. Survivin gene was transfected to DCs with liposomes. Survivin expression could be detected both in DCs cells and in cell culture with method of Western blot. Cytokines as well as cellular surface molecule such as IL-12, TNF-alpha, CD1 alpha, CD83, MHCII, CD80 and CD86 were detected. The competence of inducing human specific cytotoxic T lymphocyte (CTLs) was also detected with MTT. Survivin expression could be detected both in DCs which were transfected with survivin cDNA and in cell culture superior. The IL-12 and TNF-alpha level was (265.2 +/- 32.7), (437.1 +/- 83.5) pg/ml, and much higher in transgened DC cells than blank DC cells (P < 0.05). CD1 alpha, CD83, MHCII, CD80 and CD86 was high expressed in survivin-DC cells, however, it was low expressed in blank DC cells. The lyse rate to gastric cancer cell, colon cancer cell and bile duct cancer cell was 65%, 77%, and 85% respectively, and these were much higher than those of blank DC cells. DCs transfected with survivin gene could induce specific cytotoxic T lymphocytes and strikingly raised DC cell's antigen present function, and have specific CTL killing activity.

Effects of dendritic cells transfected with full length wild type P53 and modified by gastric cancer lysate on immune response.

To investigate the effects of dendritic cells (DCs) transfected with full length wild type p53 and modified by gastric cancer lysates on immune response, the wild type P53 was transducted to DCs with adenovirus, and the DCs were modified by gastric cancer lysates (Lywt-P53DC). The concentration of the surface molecules (B7-1, B7-2, MHC-I , MHC-II) of all DCs was determined by FACS, and the ability of the DCs to induce efficient and specific immunological response in anti-51Cr-labeled target cells studied. BALB/c mice model infected with DCs and Mk28 was established. CTL response in mice immunized with Lywt-p53DC and the effectiveness of Lywt-p53DC in the treatment of tumor-bearing mice was assayed. FACS revealed that the surface molecules of Ly-wt-P53 DC had a high expression: for B7-1 86.70% +/- 0.07%, B7-2 18.77% +/- 0.08%, MHC-I 87.20% +/- 0.05%, MHC-II 56.70%+/-0.07%; The T lymphocytes had a specific CTL lysing ability induced by Lywt-P53DC with the CTL lysis rate being 81%. The immune protective effect of Lywt-p53DC group was more obvious than any other groups (P<0.05). The tumor diameter in Lywt-p53DC group was 3.10+/-0.31 mm, 2.73+/-0.23 mm, 3.70+/-0.07 mm on the day 13, 16 and 19, smaller than DC, wtp53DC and LyDC groups (P<0.05). On the other hand, the growth rate of tumor in Lywt-p53DC group was slower than any other groups (P<0.05). It was suggested that DCs transfected with wild type P53 and modified by gastric cancer lysates had specific CTL killing capability.

Effect of dendritic cells on flow cytometric quantification of cytomegalovirus-specific, interferon-gamma-producing T cells.

Flow cytometric measurement of intracellular cytokines in T cells exposed to antigen is a widely used method for quantification of an antigen-specific T-cell response. As the frequency of antigen-specific T cells is often very low, any improvement in signal to noise ratio is of great importance. Thus, in this study, the ability of antigen-pulsed dendritic cells (DCs) to increase the number of antigen-specific, interferon-gamma (IFN-gamma)-producing CD4+ T cells measurable both in fresh peripheral blood and in reconstituted frozen blood mononuclear cell (MNC) samples was evaluated. Cytomegalovirus (CMV) was used as antigen in a 10 h assay, using cells from both CMV-seropositive and -seronegative donors. When reconstituted frozen samples were analysed, the general response towards CMV lysate in CMV-seropositive donors was 23-86% lower compared to the corresponding fresh blood samples. Antigen-pulsed DCs could not improve the sensitivity of the intracellular cytokine-detection assay when fresh peripheral blood samples were used. Interestingly, however, the addition of CMV lysate-pulsed DCs to cryopreserved MNC samples substantially increased the frequency of specifically induced IFN-gamma-producing cells to a level comparable to the frequency found in the corresponding fresh blood samples.

Overexpression of CCL-21/Secondary Lymphoid Tissue Chemokine in Human Dendritic Cells Augments Chemotactic Activities for Lymphocytes and Antigen Presenting Cells

BackgroundEx vivo generated dendritic cells (DC) genetically modified to express secondary lymphoid tissue chemokine (CCL-21/SLC) have been shown to stimulate potent antitumor responses in murine models. When injected intratumorally, CCL-21 colocalizes DC and lymphocyte effector cells at the tumor site. This may improve tumor antigen presentation and T cell activation by utilizing the tumor as an in vivo source of antigen for DC. In order to develop DC-based cancer therapies for intratumoral injection that could promote tumor antigen uptake and presentation in situ, we constructed and characterized an adenoviral vector that expresses human CCL-21 (AdCCL-21).ResultsHuman monocyte derived DC were cultured in GM-CSF and IL-4 for 6 days. Following AdCCL-21 transduction, CCL-21 protein production was assessed by ELISA on day 8. DC transduced with AdCCL-21 at multiplicities of infection (MOIs) of 50:1 or 100:1 produced up to 210 ± 9 ng/ml and 278 ± 6.5 ng/ml /106 cells/48 hours, respectively. Following transduction, an immature DC phenotype was maintained and an upregulation of the costimulatory molecule, CD86 was noted. In addition, supernatant from AdCCL-21-DC caused significant chemotaxis of peripheral blood lymphocytes and mature DC.ConclusionsThese studies demonstrate that AdCCL-21-DC generate functional levels of CCL-21 without adversely altering DC phenotype. These findings strengthen the rationale for further investigation of AdCCL-21-DC as a DC-based therapy in cancer treatment.