A rapid culture technique produces functional dendritic-like cells from human acute myeloid leukemia cell lines

Different In Vitro-Generated MUTZ-3-Derived Dendritic Cell Types Secrete Dexosomes with Distinct Phenotypes and Antigen Presentation Potencies

Human dendritic cell (DC) dexosomes were evaluated for their function and preclinical validation for vaccines. Dexosomes are small DC-secreted vesicles that contain absorbing immune signals. Vaccine manufacturing requires a significant number of monocyte-derived DCs (Mo-DCs) from donor blood; thus, Mo-DC dexosomes are expected to serve as novel materials for cancer vaccination. In this study, we characterized a potential dexosome model using immature and mature MUTZ3-derived DCs (M-imIL-4-DC, M-imIFN-DC, M-mIL-4-DC, and M-mIFN-DC) and their dexosomes (M-imIL-4-Dex, M-imIFN-Dex, M-mIL4-Dex, and M-mIFN-Dex). Despite the lack of significant differences in viability, M-mIFN-DC showed a significantly higher level of yield and higher levels of maturation surface markers, such as CD86 and HLA-ABC, than M-mIL-4-DC. In addition, M-mIFN-Dex expressed a higher level of markers, such as HLA-ABC, than M-mIL-4-Dex. Furthermore, M-mIFN-Dex exhibited a higher level of antigen presentation potency, as evaluated using a MART-1 system, than either M-imIFN-Dex or M-mIL-4-Dex. We found that M-mIFN-Dex is one of the four types of MUTZ3-derived DCs that harbor potential immunogenicity, suggesting that DC dexosomes could be useful resources in cancer immunotherapy.

Therapeutic cancer vaccine therapy for acute myeloid leukemia

Antitumor function of the immune system has been harnessed to eradicate tumor cells as cancer therapy. Therapeutic cancer vaccines aim to help immune cells recognize tumor cells, which are difficult to target owing to immune escape. Many attempts at vaccine designs have been conducted throughout the last decades. In addition, as the advanced understanding of immunosuppressive mechanisms mediated by tumor cells, combining cancer vaccines with other immune therapies seems to be more efficient for cancer treatment. Acute myeloid leukemia (AML) is the most common acute leukemia in adults with poor prognosis. Evidence has shown T-cell-mediated immune responses in AML, which encourages the utility of immune therapies in AML. This review discusses cancer vaccines in AML from vaccine design as well as recent progress in vaccination combination with other immune therapies.

Human leukocyte antigen class II quantification by targeted mass spectrometry in dendritic-like cell lines and monocyte-derived dendritic cells

The major histocompatibility complex II (HLA-II) facilitates the presentation of antigen-derived peptides to CD4+ T-cells. Antigen presentation is not only affected by peptide processing and intracellular trafficking, but also by mechanisms that govern HLA-II abundance such as gene expression, biosynthesis and degradation. Herein we describe a mass spectrometry (MS) based HLA-II-protein quantification method, applied to dendritic-like cells (KG-1 and MUTZ-3) and human monocyte-derived dendritic cells (DCs). This method monitors the proteotypic peptides VEHWGLDKPLLK, VEHWGLDQPLLK and VEHWGLDEPLLK, mapping to the α-chains HLA-DQA1, -DPA1 and -DRA1/DQA2, respectively. Total HLA-II was detected at 176 and 248 fmol per million unstimulated KG-1 and MUTZ-3 cells, respectively. In contrast, TNF- and LPS-induced MUTZ-3 cells showed a 50- and 200-fold increase, respectively, of total α-chain as measured by MS. HLA-II protein levels in unstimulated DCs varied significantly between donors ranging from ~ 4 to ~ 50 pmol per million DCs. Cell surface HLA-DR levels detected by flow cytometry increased 2- to 3-fold after DC activation with lipopolysaccharide (LPS), in contrast to a decrease or no change in total HLA α-chain as determined by MS. HLA-DRA1 was detected as the predominant variant, representing > 90% of total α-chain, followed by DPA1 and DQA1 at 3-7% and ≤ 1%, respectively.

Towards a surrogate system to express human lipid binding TCRs

BACKGROUND

Previously we reported that natural nut lipids were necessary for sensitization and that natural killer T cells (NKTs) must play a critical role in the development of food allergic responses. A major bottleneck in further understanding the interaction of nut lipids with the cells of the human immune system is the lack of well-characterized lipid responsive human cell lines.

OBJECTIVE

In the present study, we engineered human T cell receptor (TCR) sequences TRAV10 and TRBV25 responsive to α-GalCer into a stable murine iNKT hybridoma and surrogate human T cell lines.

RESULTS

The murine hybridoma system has shown to be problematic. To overcome this limitation, the expression of human TCR α/β sequences has been achieved driven by a bidirectional promoter on a plasmids or a lentivirus system, employing stable DC cell lines as lipid presenting cells, and a stable T cell line as a surrogate system. Further, a commercial human Jurkat T cell line containing an inducible secreted luciferase reporter construct was shown to be functional and can be used for a transient expression of human TCRs in a lipid screening program. The transfection efficiencies were improved using the lentivirus polycistronic constructs containing the P2A sequence in a TCR αβ/γδ null cell line (Jurkat 76).

CONCLUSIONS

The results suggest that the mis-pairing of the endogenous α/β TCR during ER folding in the presence of the new human TCR sequences could be impairing the functionality of the TCR lipid receptors. The surrogate systems presented here are important first steps in the establishment of human cell-specific lipid responsive libraries for the study of natural lipid substances.

Can Dendritic Cell Vaccination Prevent Leukemia Relapse?

Leukemias are clonal proliferative disorders arising from immature leukocytes in the bone marrow. While the advent of targeted therapies has improved survival in certain subtypes, relapse after initial therapy is a major problem. Dendritic cell (DC) vaccination has the potential to induce tumor-specific T cells providing long-lasting, anti-tumor immunity. This approach has demonstrated safety but limited clinical success until recently, as DC vaccination faces several barriers in both solid and hematological malignancies. Importantly, vaccine-mediated stimulation of protective immune responses is hindered by the aberrant production of immunosuppressive factors by cancer cells which impede both DC and T cell function. Leukemias present the additional challenge of severely disrupted hematopoiesis owing to both cytogenic defects in hematopoietic progenitors and an abnormal hematopoietic stem cell niche in the bone marrow; these factors accentuate systemic immunosuppression and DC malfunction. Despite these obstacles, several recent clinical trials have caused great excitement by extending survival in Acute Myeloid Leukemia (AML) patients through DC vaccination. Here, we review the phenotype and functional capacity of DCs in leukemia and approaches to harness DCs in leukemia patients. We describe the recent clinical successes in AML and detail the multiple new strategies that might enhance prognosis in AML and other leukemias.

Hydrogels in three-dimensional dendritic cell (MUTZ-3) culture as a scaffold to mimic human immuno competent subcutaneous tissue

The objective of this study was to develop a 3D cell culture model of the human subcutaneous tissue, allowing the prediction of the immunogenicity of subcutaneously injected therapeutic proteins. Several hydrogels were evaluated as scaffolds to mimic the human subcutaneous tissue in vitro. Cytocompatibility of the hydrogels with the human myelomonocytic cell line (MUTZ-3) was investigated, as well as their influence on cellular phenotype changes. Elastic Young's moduli in compression of the hydrogels were measured by a texture analyser and compared to ex vivo human samples. MUTZ-3 cells were differentiated into dendritic cells before embedding in hydrogels. Agarose at various concentrations (0.5%, 0.35% and 0.25% w/v), Geltrex® matrix and HyStem™ scaffold (1% w/v) displayed a wide range of elastic Young's moduli from 560 kPa to 49 kPa, compared to the reference value of 23 kPa obtained for human tissue. With the exception of HyStem™, good cytocompatibility of hydrogels was shown at the concentrations tested. An optimal combination of MUTZ-3 cells with 0.25% agarose or Geltrex® is suggested.

Dendritic cell vaccine against leukemia: advances and perspectives

As with many other types of malignancies, sustainable eradication of leukemia has been a challenge. This is related to the inevitable failure of conventional chemotherapeutic agents and radiation therapy to target the relatively quiescent leukemia stem cells, which are believed to have multidrug resistance, antiapoptotic capacity and enhanced DNA repair mechanisms allowing them to evade the immune system. Considering other therapeutic options that are minimally toxic to normal cells and effectively target not only the majority and more differentiated cancer cells, but also the rare residual leukemia cells, is of paramount importance. A number of immunotherapeutic options have been proposed to counter this challenge. One of the remarkable achievements in the field of immunotherapy has been the successful use of antigen presenting cells as vehicles of tumor/pathogenic antigens to the T-cell compartments. This review will focus on advances and perspectives of this arm of immunotherapy against leukemia.