ISSN:1524-9557    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Among the many promising cancer immunotherapeutic strategies, dendritic cells (DC) have become of particular interest. This study aims to optimize a clinical grade protocol for culture and transfection of human DC. Monocytes and CD34+hematopoietic stem cells (HSC) from same donor were differentiated under serum-free conditions and analyzed for their susceptibility to several recently described nonviral transfection methods as compared with established virally mediated gene transfer. Nonviral gene transfer methods studied were square-wave electroporation, lipofection, and particle-mediated transfer of plasmid DNA or in vitro transcribed mRNA. We conclude that DNA is not suitable for transduction of DC using nonviral methods. In contrast, mRNA and square-wave electroporation reproducibly yields 60% and 50% transfected monocyte- and CD34+-derived DC, respectively, measured at protein level, without affecting the cell viability. Thus, the transfection efficiency of this method is comparable with the 40–90% transgene expression obtained using retroviral (RV) or adenoviral (AdV) vectors in CD34+- and monocyte-derived DC, respectively. In monocyte-derived DC, however, the amount of protein expressed per-cell basis was higher after AdV (MOI = 1000) compared with mRNA electroporation-mediated transfer. This is the first study directly demonstrating side-by-side that mRNA electroporation into DC of different origin indeed results in a comparable number of transduced cells as when using virus-mediated gene transfer.

ISSN:1524-9557    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

CTLA4 is a negative regulator of the costimulatory signals induced by the interaction of CD28 on T cells and B7 on dendritic cells (DCs). Antibodies (Abs) against CTLA4 can block its function and increase the activation of T cells primed to recognize antigens. The effect of CTLA4 blockade on the cross-presentation of tumor antigens by DCs to T cells was examined. Immune T cells and DC precursors were collected from patients receiving idiotype protein-pulsed DC vaccines, exposed to antigen, and examined for antitumor activity by measuring intracellular cytokine production by FACS. Idiotype-specific activation occurred in CD8+and CD4+T-cell populations and was up to 58 fold higher with CTLA4 blockade. These T cells could be expanded quickly and maintained tumor cytolytic activity. T-cell responses to whole tumor cell-pulsed DCs were then examined. DCs contain Fc receptors and efficiently phagocytose lymphoma cells when coated with opsonizing anti-CD20 Abs. Within a few hours, DCs ingested tumor cells and labeled proteins were observed in the cytoplasm. When anti-CD20 Ab-coated tumor-pulsed DCs were used in combination with CTLA4 blockade, up to 15 fold higher activation of Id-specific CD8+and 3 fold higher CD4+T cells resulted. Thus, CTLA4 blockade can enhance the measurement of Ag-specific T-cell responses and the expansion of T cells for clinical studies. In addition, the combination of CTLA4 blockade and Ab targeting of tumor to DCs is an effective method for the cross-presentation of tumor cell antigens.

ISSN:1524-9557    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

The BCR-ABL fusion proteins, b2a2 and b3a2, are potential targets for a beneficial graft-versus-leukemia (GVL) effect after allogeneic stem cell transplantation for chronic myeloid leukemia (CML). This study demonstrates that CD4+T cells specific to the b2a2 peptide can be generated from a normal allogeneic stem cell transplant donor after stimulation with monocyte-derived dendritic cells (Mo-DC) using culture conditions applicable to clinical use. Stimulation of donor T-cell enriched mononuclear cells (MNC) with b2a2-pulsed Mo-DC produced approximately 3 × 109b2a2-specific CD4+T cells. The CD4+T cells were HLA-DR7 restricted. These results confirm that the generation of donor derived b2a2-specific T cells for clinical use is feasible and warrants clinical testing after stem cell transplantation.

ISSN:1524-9557    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Previous studies from our laboratory demonstrated that CD44 knockout mice exhibit marked decrease in interleukin (IL)-2-induced vascular leak syndrome (VLS), thereby suggesting a role for CD44 in VLS. In the current study, we tested whether treatment with mAbs against CD44 or hyaluronic acid (HA), the ligand for CD44, can abrogate IL-2-induced VLS. Interestingly, administration of HA caused a marked increase in IL-2-induced VLS in the lungs and liver of C57BL/6 mice. In contrast, use of anti-CD44 mAbs reduced IL-2-induced VLS in the lungs and liver. Treatment with HA enhanced the IL-2-induced edema and lymphocytic infiltration in these organs and caused marked increase in IL-2-induced lymphokine-activated killer (LAK) cell activity, whereas administration of anti-CD44 mAbs caused a significant decrease in edema and LAK activity but similar levels of lymphocytic infiltration. Anti-CD44 mAbs, but not HA caused marked downregulation of CD44 expression on LAK cells. These studies demonstrate that molecular targeting of CD44 may serve as a useful tool to selectively alter the LAK activity and to prevent endothelial cell injury induced by IL-2.

ISSN:1524-9557    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Interferon (IFN)-&ggr; and Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) enhance tumor immunogenicity. The authors assessed tolerability and effectiveness of a combination therapy of these recombinant human (rh) cytokines in patients with inoperable hepatocellular carcinoma (HCC). In a monocentric, open, nonrandomized pilot study, rhGM-CSF (5 &mgr;g/kg qd, Monday and Tuesday) and rhIFN-&ggr; (100 &mgr;g qd, Wednesday and Thursday) were subcutaneously administered in 9-week cycles. Primary objective was survival, as secondary outcomes volumetric changes of tumor mass and biologic parameters reflecting systemic immunologic or local tumor responses were measured. Only patients with complete response (CR), partial response (PR), or stable disease (SD) proceeded to new treatment cycles. Fifteen patients (median 63 years, range 46–74 years, all men) were enrolled. Survival after the first cycle was 80% with SD in 9 of 15 patients (60%). PR was detected in one patient after the second cycle. Two patients finished five treatment cycles. Overall survival at 26 and 52 weeks was 40% and 20%, respectively. Median survival in patients with inducible HLA-DR on hepatoma cells (40%) was increased (42 weeks, 27–100) as compared with HLA-DR negative cases (60%; 13 weeks, 8–23; p < 0.0001), and a control group (p = 0.01). Parameters reflecting systemic immunomodulatory activities were not associated with clinical outcome. In 13 of 15 patients (87%), adverse events were reported, all less than grade 2 and none requiring therapy discontinuation. Immunotherapeutic approaches hold promise to prolong survival in selected patients with advanced HCC who respond by enhanced tumor immunogenicity.

ISSN:1524-9557    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

Dendritic cells (DC) have been recognized as the most potent antigen presenting cells (APC) of the immune system. We performed a phase 1 study in twelve patients with metastatic renal cell carcinoma (RCC) using autologous immature DC loaded with autologous tumorlysate (TuLy) as a vaccine based on our earlier in vitro observations that such DC can activate tumor-specific cytotoxic T-lymphocytes. The treatment was combined with low-dose interleukin (IL)-2, as this has shown benefit in DC-based therapies. Patients received three intradermal vaccinations at two weekly intervals, and, after each vaccination, IL-2 was administered for 5 consecutive days. In six patients, keyhole-limpet hemocyanin (KLH) was added to the DC culture for immunologic monitoring purposes. In general, DC phenotype was CD14low, CD86high, CD40high, CD80low, and CD83low. We noticed that the number of CD14+cultured DC increased during treatment. Nevertheless, ovalbumin uptake remained high, underlining that these cells were still functional immature DC. The vaccine was able to elicit cellular anti-KLH responses, emphasizing the ability of the injected DC to mount an immunologic response. However, proliferative responses against TuLy were not detected, and humoral responses against TuLy or KLH were absent. Objective clinical responses were not observed, but extended stable disease was noted. The absence of cellular, humoral, or clinical antitumor responses suggests that the vaccination strategy with immature DC has little benefit for patients with advanced RCC. Nevertheless, this study shows the feasibility of a completely autologous DC and tissue culture methodology for the generation of TuLy pulsed DC.

ISSN:1524-9557    

出版商:OVID    

年代:2002

数据来源: OVID