A method for the generation of large numbers of dendritic cells from CD34+ hematopoietic stem cells from cord blood

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.

Isolation and culture of chicken bone marrow-derived CD34+ hematopoietic stem and progenitor cells and induced differentiation to myeloid cells

Hematopoietic stem and progenitor cell (HSPC) research will help elucidate the pathogenesis of hematologic diseases. The present study aimed to establish an isolation method and culture system for chicken bone marrow (BM)-derived HSPCs and test their proliferation and differentiation abilities. Mononuclear cells were collected from chicken BM, and CD34+ HSPCs were isolated. Then, the cells were cultured in media with different cytokine compositions, and the growth status, cell phenotype, and morphological appearance of the cells were analyzed at different time points. Our results showed that Iscove's Modified Dulbecco's Medium supplemented with 50 ng/mL stem cell factor, 30 ng/mL Flt-3 ligand, 10 μg/mL interleukin 3, 50 ng/mL interleukin 6%, and 10% chicken serum supported chicken CD34+ HSPC survival ex vivo for approximately 10 d. Further, 80 ng/mL granulocyte-colony stimulating factor and 30 ng/mL granulocyte macrophage-colony stimulating factor were added into the above culture system to form a myeloid cell differentiation induction culture system. After culturing in this system for 72 h, approximately 66% of chicken CD34+ HSPCs exhibited a CD11b+ phenotype, indicating that HSPCs differentiated into myeloid cells. In conclusion, chicken BM-derived CD34+ cells possess HSPC characteristics that can self-renew and differentiate into myeloid cells in a culture medium containing growth factors.

Impact of intravenous fluid administration on cardiac output and oxygenation during cardiopulmonary resuscitation

BACKGROUND

The effect of intravenous fluid (IVF) administration during cardiopulmonary resuscitation (CPR) is an unexplored factor that may improve cardiac output (CO) during CPR. The aim of this study was to determine the effect of IVF administration on CO and oxygenation during CPR.

METHODS

This experimental animal study was performed in a critical care animal laboratory. Twenty-two Landrace-Yorkshire female piglets weighing 27-37 kg were anesthetized, intubated, and placed on positive pressure ventilation. Irreversible cardiac arrest was induced with bupivacaine. CPR was performed with a LUCAS 3 mechanical compression device. Pigs were randomized into IVF or no-IVF groups. Pigs in the IVF group were given 20 mL/kg of Plasma-Lyte (Baxter International, Deerfield, IL USA), infused from 15 to 35 min of CPR. CPR was maintained for 50 min with serial measurements of CO obtained using ultrasound dilution technology and partial pressure of oxygen (PaO₂).

RESULTS

A mixed-effects repeated measures analysis of variance was used to compare within-group, and between-group mean changes in CO and PaO₂ over time. CO and PaO₂ for the piglets were measured at 10-min intervals during the 50 min of CPR. CO was greater in the IVF compared with the control group at all time points during and after the infusion of the IVF. Mean PaO₂ decreased with time; however, at no time was there a significant difference in PaO₂ between the IVF and control groups.

CONCLUSIONS

Administration of IVF during CPR resulted in a significant increase in CO during CPR both during and after the IVF infusion. There was no statistically significant decrease in PaO₂ between the IVF and control groups.

Dendritic cell transfer for cancer immunotherapy

Dendritic cells (DCs) play a major role in cancer immunosurveillance as they bridge innate and adaptive immunity by detecting tumor-associated antigens and presenting them to T lymphocytes. The adoptive transfer of antigen loaded DCs has been proposed as an immunotherapeutic approach for the treatment of various types of cancer. Nevertheless, despite promising preclinical data, the therapeutic efficacy of DC transfer is still deceptive in cancer patients. Here we summarize recent findings in DC biology with a special focus on the development of actionable therapeutic strategies and discuss experimental and clinical approaches that aim at improving the efficacy of DC-based immunotherapies, including, but not limited to, optimized DC production and antigen loading, stimulated maturation, the co-treatment with additional immunotherapies, as well as the inhibition of DC checkpoints.

Alloantigen-activated (AAA) CD4+ T cells reinvigorate host endogenous T cell immunity to eliminate pre-established tumors in mice

BACKGROUND

Cancer vaccines that induce endogenous antitumor immunity represent an ideal strategy to overcome intractable cancers. However, doing this against a pre-established cancer using autologous immune cells has proven to be challenging. "Allogeneic effects" refers to the induction of an endogenous immune response upon adoptive transfer of allogeneic lymphocytes without utilizing hematopoietic stem cell transplantation. While allogeneic lymphocytes have a potent ability to activate host immunity as a cell adjuvant, novel strategies that can activate endogenous antitumor activity in cancer patients remain an unmet need. In this study, we established a new method to destroy pre-developed tumors and confer potent antitumor immunity in mice using alloantigen-activated CD4⁺ (named AAA-CD4⁺) T cells.

METHODS

AAA-CD4⁺ T cells were generated from CD4⁺ T cells isolated from BALB/c mice in cultures with dendritic cells (DCs) induced from C57BL/6 (B6) mice. In this culture, allogeneic CD4⁺ T cells that recognize and react to B6 mouse-derived alloantigens are preferentially activated. These AAA-CD4⁺ T cells were directly injected into the pre-established melanoma in B6 mice to assess their ability to elicit antitumor immunity in vivo.

RESULTS

Upon intratumoral injection, these AAA-CD4⁺ T cells underwent a dramatic expansion in the tumor and secreted high levels of IFN-γ and IL-2. This was accompanied by markedly increased infiltration of host-derived CD8⁺ T cells, CD4⁺ T cells, natural killer (NK) cells, DCs, and type-1 like macrophages. Selective depletion of host CD8⁺ T cells, rather than NK cells, abrogated this therapeutic effect. Thus, intratumoral administration of AAA-CD4⁺ T cells results in a robust endogenous CD8⁺ T cell response that destroys pre-established melanoma. This locally induced antitumor immunity elicited systemic protection to eliminate tumors at distal sites, persisted over 6 months in vivo, and protected the animals from tumor re-challenge. Notably, the injected AAA-CD4⁺ T cells disappeared within 7 days and caused no adverse reactions.

CONCLUSIONS

Our findings indicate that AAA-CD4⁺ T cells reinvigorate endogenous cytotoxic T cells to eradicate pre-established melanoma and induce long-term protective antitumor immunity. This approach can be immediately applied to patients with advanced melanoma and may have broad implications in the treatment of other types of solid tumors.

Comparison of the PU.1 transcriptional regulome and interactome in human and mouse inflammatory dendritic cells

Dendritic cells (DCs) are key immune modulators and are able to mount immune responses or tolerance. DC differentiation and activation imply a plethora of molecular and cellular responses, including transcriptional changes. PU.1 is a highly expressed transcription factor in DCs and coordinates relevant aspects of DC biology. Due to their role as immune regulators, DCs pose as a promising immunotherapy tool. However, some of their functional features, such as survival, activation, or migration, are compromised due to the limitations to simulate in vitro the physiologic DC differentiation process. A better knowledge of transcriptional programs would allow the identification of potential targets for manipulation with the aim of obtaining "qualified" DCs for immunotherapy purposes. Most of the current knowledge regarding DC biology derives from studies using mouse models, which not always find a parallel in human. In the present study, we dissect the PU.1 transcriptional regulome and interactome in mouse and human DCs, in the steady state or LPS activated. The PU.1 transcriptional regulome was identified by performing PU.1 chromatin immunoprecipitation followed by high-throughput sequencing and pairing these data with RNAsequencing data. The PU.1 interactome was identified by performing PU.1 immunoprecipitation followed by mass spectrometry analysis. Our results portray PU.1 as a pivotal factor that plays an important role in the regulation of genes required for proper DC activation and function, and assures the repression of nonlineage genes. The interspecies differences between human and mouse DCs are surprisingly substantial, highlighting the need to study the biology of human DCs.