Fcγ receptors and toll-like receptor 9 synergize to drive immune complex-induced dendritic cell maturation

Bicalutamide reveals immunomodulatory effects in prostate cancer by regulating immunogenic dendritic cell maturation

Prostate cancer poses a significant global health challenge, ranking as the second most prevalent and fifth most lethal malignancy among males. The intricate interplay between androgen signaling and the immune microenvironment underscores the complexity of prostate cancer progression. Notably, androgen receptor (AR) signaling has been shown to affect immune response mediated by tumor antigen-presenting dendritic cells (DCs). Therefore, this study aimed to explore the potential of Bicalutamide, a nonsteroidal anti-androgen, in modulating DCs-mediated immune responses. Peripheral blood mononuclear cells (PBMCs) were isolated, and monocytes were extracted, followed by their differentiation into immature dendritic cells (iDCs) using GM-CSF and IL-4. Harvested tumor cell lysates from human prostate cancer cells were then utilized to induce the transformation of iDCs into mature dendritic cells (mDCs). Then, mDCs were treated with non-toxic concentration of Bicalutamide determined by annexin V/PI assay. The morphological characteristics of mDCs were investigated using an inverted light microscope. Flow cytometry was used to determine the cell surface expression of molecular markers of DC maturation, and qRT-PCR was employed to evaluate expression levels of proinflammatory genes involved in DC maturation. The obtained results indicated that Bicalutamide treatment of monocyte-derived mDCs induces an immunogenic and matured phenotype, marked by increased expression of CD86 and HLA-DR. Besides, qRT-PCR results evidenced that Bicalutamide decreased the expression of anti-inflammatory genes, including Interleukin-10 (IL-10) and TGF-beta, as an indication of immunogenic DCs. These findings suggest that beyond its established anti-androgen role, Bicalutamide may exert anti-tumor effects through the modulation of DCs-mediated immune responses. This novel immunomodulatory feature holds promise for the development of novel therapies, including combination therapies, in prostate cancer treatment.

Perspective view of allogeneic IgG tumor immunotherapy

Allogeneic tumors are eradicated by host immunity; however, it is unknown how it is initiated until the report in Nature by Yaron Carmi et al. in 2015. Currently, we know that allogeneic tumors are eradicated by allogeneic IgG via dendritic cells. AlloIgG combined with the dendritic cell stimuli tumor necrosis factor alpha and CD40L induced tumor eradication via the reported and our proposed potential signaling pathways. AlloIgG triggers systematic immune responses targeting multiple antigens, which is proposed to overcome current immunotherapy limitations. The promising perspectives of alloIgG immunotherapy would have advanced from mouse models to clinical trials; however, there are only 6 published articles thus far. Therefore, we hope this perspective view will provide an initiative to promote future discussion.

Use of Magnetotactic Bacteria as an MRI Contrast Agent for In Vivo Tracking of Adoptively Transferred Immune Cells

PURPOSE

In vivo immune cell tracking using MRI can be a valuable tool for studying the mechanisms underlying successful cancer therapies. Current cell labeling methods using superparamagnetic iron oxide (SPIO) lack the persistence to track the fate and location of transplanted cells long-term. Magnetospirillum magneticum is a commercially available, iron-producing bacterium that can be taken up by and live harmoniously within mammalian cells as magneto-endosymbionts (MEs). MEs have shown promise as labeling agents for in vivo stem and cancer cell tracking but have yet to be evaluated in immune cells. This pilot study examined ME labeling in myeloid-derived suppressor cells (MDSCs), cytotoxic T lymphocytes (CTLs), and dendritic cells (DCs) and its effects on cell purity, function, and MRI contrast.

PROCEDURES

MDSCs, CTLs, and DCs were incubated with MEs at various ME labeling ratios (MLR), and various biological metrics and iron uptake were assessed. For in vivo imaging, MDSCs were labeled overnight with either MEs or SPIO (Molday ION Rhodamine B) and injected into C3 tumor-bearing mice via tail vein injection 24 days post-implant and scanned daily with MRI for 1 week to assess cellular quantification.

RESULTS

Following incubations, MDSCs contained > 0.6 pg Fe/cell. CTLs achieved Fe loading of < 0.5 pg/cell, and DCs achieved Fe loading of ~ 1.4 pg/cell. The suppressive functionality of MDSCs at 1000 MLR was not affected by ME labeling but was affected at 2000 MLR. Markers of CTL dysfunction were not markedly affected by ME labeling nor were DC markers. In vivo data demonstrated that the MDSCs labeled with MEs generated sufficient contrast to be detectable using TurboSPI, similar to SPIO-labeled cells.

CONCLUSIONS

Cells can be labeled with sufficient numbers of MEs to be detectable with MRI without compromising cell viability. Care must be taken at higher concentrations of MEs, which may affect some cell types' functional activity and/or morphology. Immune cells with minimal phagocytic behavior have much lower iron content per cell after incubation with MEs vs SPIO; however, MEs can successfully be used as a contrast agent for phagocytic immune cells.

The performance and perspectives of dendritic cell vaccines modified by immune checkpoint inhibitors or stimulants

Therapeutic dendritic cell (DC) vaccines stimulate the elimination of tumor cells by the immune system. However, while antigen-specific T cell responses induced by DC vaccines are commonly observed, the clinical response rate is relatively poor, necessitating vaccine optimization. There is evidence that the suppression of DC function by immune checkpoints hinders the anti-tumor immune responses mediated by DC vaccines, ultimately leading to the immune escape of the tumor cells. The use of immune checkpoint inhibitors (ICIs) and immune checkpoint activators (ICAs) has extended the immunotherapeutic range. It is known that both inhibitory and stimulatory checkpoint molecules are expressed by most DC subsets and can thus be used to manipulate the effectiveness of DC vaccines. Such manipulation has been investigated using strategies such as chemotherapy, agonistic or antagonistic antibodies, siRNA, shRNA, CRISPR-Cas9, soluble antibodies, lentiviruses, and adenoviruses to maximize the efficacy of DC vaccines. Thus, a deeper understanding of immune checkpoints may assist in the development of improved DC vaccines. Here, we review the actions of various ICIs or ICAs shown by preclinical studies, as well as their potential application in DC vaccines. New therapeutic interventional strategies for blocking and stimulating immune checkpoint molecules in DCs are also described in detail.

Francisella and Antibodies

Immune responses to intracellular pathogens depend largely upon the activation of T helper type 1-dependent mechanisms. The contribution of B cells to establishing protective immunity has long been underestimated. Francisella tularensis, including a number of subspecies, provides a suitable model for the study of immune responses against intracellular bacterial pathogens. We previously demonstrated that Francisella infects B cells and activates B-cell subtypes to produce a number of cytokines and express the activation markers. Recently, we documented the early production of natural antibodies as a consequence of Francisella infection in mice. Here, we summarize current knowledge on the innate and acquired humoral immune responses initiated by Francisella infection and their relationships with the immune defense systems.