Generation of large numbers of highly purified dendritic cells from bone marrow progenitor cells after co-culture with syngeneic murine splenocytes

The Potential of Dendritic Cell Subsets in the Development of Personalized Immunotherapy for Cancer Treatment

Since the discovery of dendritic cells (DCs) in 1973 by Ralph Steinman, a tremendous amount of knowledge regarding these innate immunity cells has been accumulating. Their role in regulating both innate and adaptive immune processes is gradually being uncovered. DCs are proficient antigen-presenting cells capable of activating naive T-lymphocytes to initiate and generate effective anti-tumor responses. Although DC-based immunotherapy has not yielded significant results, the substantial number of ongoing clinical trials underscores the relevance of DC vaccines, particularly as adjunctive therapy or in combination with other treatment options. This review presents an overview of current knowledge regarding human DCs, their classification, and the functions of distinct DC populations. The stepwise process of developing therapeutic DC vaccines to treat oncological diseases is discussed, along with speculation on the potential of combined therapy approaches and the role of DC vaccines in modern immunotherapy.

The emerging role of regulatory cell-based therapy in autoimmune disease

Autoimmune disease, caused by unwanted immune responses to self-antigens, affects millions of people each year and poses a great social and economic burden to individuals and communities. In the course of autoimmune disorders, including rheumatoid arthritis, systemic lupus erythematosus, type 1 diabetes mellitus, and multiple sclerosis, disturbances in the balance between the immune response against harmful agents and tolerance towards self-antigens lead to an immune response against self-tissues. In recent years, various regulatory immune cells have been identified. Disruptions in the quality, quantity, and function of these cells have been implicated in autoimmune disease development. Therefore, targeting or engineering these cells is a promising therapeutic for different autoimmune diseases. Regulatory T cells, regulatory B cells, regulatory dendritic cells, myeloid suppressor cells, and some subsets of innate lymphoid cells are arising as important players among this class of cells. Here, we review the roles of each suppressive cell type in the immune system during homeostasis and in the development of autoimmunity. Moreover, we discuss the current and future therapeutic potential of each one of these cell types for autoimmune diseases.

Discrimination of the heterogeneity of bone marrow‑derived dendritic cells

The present study aimed to discriminate different subsets of cultured dendritic cells (DCs) to evaluate their immunological characteristics. DCs offer an important foundation for immunological studies, and mouse bone marrow (BM) cells cultured with granulocyte-macrophage colony-stimulating factor (GM-CSF) have been used extensively to generate CD11c⁺/major histocompatibility complex II⁺ BM-derived DCs (BMDCs). Immature DCs are considered to have strong migration and phagocytic antigen-capturing abilities, whereas mature DCs are thought to activate naive T cells and express high levels of costimulatory cytokines and adhesion molecules. In most culture systems, non-adherent cells are collected as mature and qualified DCs, and the remaining adherent cells are discarded. The output from GM-CSF cultures comprises mostly adherent cells, and only a small portion of them is non-adherent. This situation has resulted in ambiguities in the attempts to understand results from the use of cultured DCs. In the present study, DCs were divided into three subsets: i) Non-adherent cells; ii) adherent cells and iii) mixed cells. The heterogeneous features of cultured DCs were identified by evaluating the maturation status, cytokine secretion and the ability to activate allogeneic T cells according to different subsets. Results from the study demonstrated that BMDC culture systems were a heterogeneous group of cells comprising non-adherent cells, adherent cells, mixed cells and firmly adherent cells. Non-adherent cells may be used in future studies that require relatively mature DCs such as anticancer immunity. Adherent cells may be used to induce tolerance DCs, whereas mixed cells may potentiate either tolerogenicity or pro-tumorigenic responses. Firmly adherent cells were considered to have macrophage-like properties. The findings may aid in immunological studies that use cultured DCs and may lead to more precise DC research.

Regulation of PGE2 signaling pathways and TNF-alpha signaling pathways on the function of bone marrow-derived dendritic cells and the effects of CP-25

This study was to investigate PGE2 and TNF-alpha signaling pathway involving in the maturation and activation of bone marrow dendritic cells (DCs) and the effect of CP-25. Bone marrow DCs were isolated and stimulated by PGE2 and TNF-alpha respectively. The markers of maturation and activation expressed on DCs, such as CD40, CD80, CD83, CD86, MHC-II, and the ability of antigen uptake of DCs were analyzed by flow cytometry. The proliferation of T cells co-cultured with DCs, the signaling pathways of PGE2-EP4-cAMP and TNF-alpha-TRADD-TRAF2-NF-κB in DCs were analyzed. The results showed that both PGE2 and TNF-alpha up-regulated the expressions of CD40, CD80, CD83, CD86, and MHC-II, decreased the antigen uptake of DCs, and DCs stimulated by PGE2 or TNF-alpha could increase T cell proliferation. CP-25 (10(-5), 10(-6), and 10(-7)mol/l) decreased significantly the expressions of CD40, CD80, CD83, CD86 and MHC-II, increased the antigen uptake of DCs, and suppressed T cell proliferation induced by DCs. PGE2 increased the expressions of EP4, NF-κB and down-regulated cAMP level of DCs. TNF-alpha could also up-regulate TNFR1, TRADD, TRAF2, and NF-κB expression of DCs. CP-25 (10(-5), 10(-6), and 10(-7)mol/l) decreased the expressions of EP4 and NF-κB, increased cAMP level in DCs stimulated by PGE2. CP-25 (10(-5), 10(-6), and 10(-7)mol/l) also could down-regulate significantly TNFR1, TRADD, TRAF2, and NF-κB expression in DCs stimulated by TNF-alpha. These results demonstrate that PGE2 and TNF-alpha could enhance DCs functions by mediating PGE2-EP4-cAMP pathway, TNF-alpha-TNFR1-TRADD-TRAF2-NF-κB pathway respectively. CP-25 might inhibit the function of DCs through regulating PGE2-EP4-cAMP and TNF-alpha-TNFR1-TRADD-TRAF2-NF-κB pathways.

T-cell mediated anti-tumor immunity after photodynamic therapy: why does it not always work and how can we improve it?

Photodynamic therapy (PDT) uses the combination of non-toxic photosensitizers and harmless light to generate reactive oxygen species that destroy tumors by a combination of direct tumor cell killing, vascular shutdown, and activation of the immune system. It has been shown in some animal models that mice that have been cured of cancer by PDT, may exhibit resistance to rechallenge. The cured mice can also possess tumor specific T-cells that recognize defined tumor antigens, destroy tumor cells in vitro, and can be adoptively transferred to protect naïve mice from cancer. However, these beneficial outcomes are the exception rather than the rule. The reasons for this lack of consistency lie in the ability of many tumors to suppress the host immune system and to actively evade immune attack. The presence of an appropriate tumor rejection antigen in the particular tumor cell line is a requisite for T-cell mediated immunity. Regulatory T-cells (CD25+, Foxp3+) are potent inhibitors of anti-tumor immunity, and their removal by low dose cyclophosphamide can potentiate the PDT-induced immune response. Treatments that stimulate dendritic cells (DC) such as CpG oligonucleotide can overcome tumor-induced DC dysfunction and improve PDT outcome. Epigenetic reversal agents can increase tumor expression of MHC class I and also simultaneously increase expression of tumor antigens. A few clinical reports have shown that anti-tumor immunity can be generated by PDT in patients, and it is hoped that these combination approaches may increase tumor cures in patients.

Interleukin-4 affects the mature phenotype and function of rat bone marrow-derived dendritic cells

Granulocyte macrophage‑colony stimulating factor (GM‑CSF), and GM‑CSF plus interleukin‑4 (GM‑CSF + IL‑4) are two commonly‑used cytokine therapies for the generation of bone marrow‑derived dendritic cells (DCs). However, the mechanisms underlying IL‑4 involvement in DC generation and maturation remain unclear. In order to investigate the effect of IL‑4 on DC generation, DCs from rat bone marrow progenitors were generated using GM‑CSF, with and without IL‑4. GM‑CSF + IL‑4 DCs exhibited more mature phenotypes, and the levels of naïve allogeneic T cell stimulation were greater compared with GM‑CSF DCs. Phosphorylated signal transducer and activator of transcription 6 (p‑STAT6), the active form of STAT6, was expressed in GM‑CSF + IL‑4 DCs but not in GM‑CSF DCs. The present study demonstrated that IL‑4 influences DC morphology and immune function, and that this process may be associated with the activation of STAT6.

Characteristics of immunogenic and tolerogenic dendritic cells within the arterial wall in atherosclerosis and in vitro

AIM

To investigate the characteristic of mature dendritic cell (mDC) and tolerogenic dendritic cell (TDC) in human lower limb atherosclerosis occlusion syndrome (ASO) and diabetic foot and in vitro.

METHODS

58 human ASO and diabetic foot arterial specimens were collected from surgical operation and autopsy. Immunohistochemical and Western blotting method were used to examine the distribution and the content of CD83 and CD1a positive reaction mDC and CD11b and DC-SIGN positive reaction TDC. Furthermore, bone marrow-derived DCs were induced by rmGM-CSF and rmIL-4 in the presence or absence of LPS in vitro. The percent of CD11c(+)CD11b(+)TDC and CD11c(+)CD83(+)mDC were analyzed by flow cytometry. The effects of TDC and mDC on T lymphocytes were analyzed by the IL-17 level, the percent of Th17, and IL-17 mRNA expression.

RESULTS

Immunogenicity mDC was heavily found in intima plaque and around the small vessel of adventitia on artherosclerosis aorta of lesion group, and was positively correlated to the progress of the disease. However, there were low expression of TDC and was negatively correlated to the progress of the disease. Meanwhile, we found that there is a close relationship between high glucose and disease progression. TDC expressed high levels of IL-10 and TGF-β1 and down-regulated the percent of CD4(+)IL-17(+) Th17, IL-17 mRNA and the level of IL-17 in vitro.

CONCLUSION

TDC and mDC are assembled in the process of ASO, and the progression of the disease might be aggravated by DC-maturation. High glucose might closely relate to the progression of atherosclerosis.

Generation and characterization of regulatory dendritic cells derived from murine induced pluripotent stem cells

Regulatory dendritic cells (DCregs) represent a potential therapeutic tool for assessing a variety of immune overreaction conditions; however, current approaches for generating DCregs for therapeutic purposes are limited. We attempted to generate and characterize DCregs from murine induced pluripotent stem (iPS) cells. The iPS cells co-cultured with OP9 cells displayed mesodermally differentiated flat colonies. GM-CSF drove most of the colonies exhibiting a differentiated morphology. Thereafter, cells became morphologically heterologous under the effects of TGF-β and IL-10. Most of the floating cells developed an irregular shape with areas of protrusion. The generated iPS-DCregs demonstrated high CD11b/c and low CD40, CD80, CD86 and MHC-II expressions with a high antigen uptake ability and poor T-cell stimulatory function. Importantly, iPS-DCregs showed immune responsiveness regulation effects both in vitro and in vivo and the ability to generate regulatory T-cells in vitro. Our result illustrates a feasible approach for generating functional DCregs from murine iPS cells.

Effect of bone marrow-derived CD11b(+)F4/80 (+) immature dendritic cells on the balance between pro-inflammatory and anti-inflammatory cytokines in DBA/1 mice with collagen-induced arthritis

OBJECTIVE

To explore the effect of bone marrow-derived CD11b(+)F4/80(+) immature dendritic cells (BM CD11b(+)F4/80(+)iDC) on the balance between pro-inflammatory and anti-inflammatory cytokines in DBA/1 mice with collagen-induced arthritis (CIA).

METHODS

BM CD11b(+)F4/80(+)iDC were induced with rmGM-CSF and rmIL-4, and were identified by the expressions of toll-like receptor 2 (TLR-2), indoleamine 2,3-deoxygenase (IDO), interleukin (IL)-10, transforming growth factor (TGF)-β1 and mixed leukocyte reaction (MLR). CIA was established in DBA/1 mice by immunization with type II collagen. CIA mice were injected intravenously with BM CD11b(+)F4/80(+)iDC three times after immunization. The effect of BM CD11b(+)F4/80(+)iDC on CIA was evaluated by the arthritis index, joint histopathology, body weight, thymus index, thymocytes proliferation, IL-1β, tumor necrosis factor (TNF)-α, IL-17, IL-10 and TGF-β1 levels.

RESULTS

BM CD11b(+)F4/80(+)iDC induced with rmGM-CSF and rmIL-4 expressed high levels of TLR-2, IDO, IL-10 and TGF-β1. Infusion of BM CD11b(+)F4/80(+)iDC in CIA mice significantly reduced the arthritis index and pathological scores of joints, recovered the weight, decreased the thymus index and inhibited thymocyte proliferation. Levels of IL-1β, TNF-α and IL-17 were decreased in BM CD11b(+)F4/80(+)iDC-treated mice.

CONCLUSIONS

BM CD11b(+)F4/80(+)iDC can be induced successfully with rmGM-CSF and rmIL-4. BM CD11b(+)F4/80(+)iDC treatment can ameliorate the development and severity of CIA by regulating the balance between pro-inflammatory cytokines and anti-inflammatory cytokines.