The identification of activated T-lymphocytes restricted to myelin-derived immunogenic peptides in multiple sclerosis (MS) and aquaporin-4 water channel in neuromyelitis optica (NMO) in the blood of patients opened the possibility for developing highly selective and disease-specific therapeutic approaches. Antigen presenting cells and in particular dendritic cells (DCs) represent a strategy to inhibit pro-inflammatory T helper cells. DCs are located in peripheral and lymphoid tissues and are essential for homeostasis of T cell-dependent immune responses. The expression of a particular set of receptors involved in pathogen recognition confers to DCs the property to initiate immune responses. However, in the absence of danger signals different DC subsets have been revealed to induce active tolerance by inducing regulatory T cells, inhibiting pro-inflammatory T helper cells responses or both. Interestingly, several protocols to generate clinical-grade tolerogenic DC (Tol-DC) in vitro have been described, offering the possibility to restore the homeostasis to central nervous system-related antigens. In this review, we discuss about different DC subsets and their role in tolerance induction, the different protocols to generate Tol-DCs and preclinical studies in animal models as well as describe recent characterization of Tol-DCs for clinical application in autoimmune diseases and in particular in MS and NMO patients. In addition, we discuss the clinical trials ongoing based on Tol-DCs to treat different autoimmune diseases.

Background: Immune check-point blockade (ICB) has shown clinical benefit in mismatch repair-deficient/microsatellite instability high metastatic colorectal cancer (mCRC) but not in mismatch repair-proficient/microsatellite stable patients. Cancer vaccines with autologous dendritic cells (ADC) could be a complementary therapeutic approach to ICB as this combination has the potential to achieve synergistic effects. Methods: This was a Phase I/II multicentric study with translational sub-studies, to evaluate the safety, pharmacodynamics and anti-tumor effects of Avelumab plus ADC vaccine in heavily pre-treated MSS mCRC patients. Primary objective was to determine the maximum tolerated dose and the efficacy of the combination. The primary end-point was 40% progression-free survival at 6 months with a 2 Simon Stage. Results: A total of 28 patients were screened and 19 pts were included. Combined therapy was safe and well tolerated. An interim analysis (Simon design first-stage) recommended early termination because only 2/19 (11%) patients were disease free at 6 months. Median PFS was 3.1 months [2.1–5.3 months] and overall survival was 12.2 months [3.2–23.2 months]. Stimulation of immune system was observed in vitro but not clinically. The evaluation of basal RNA-seq noted significant changes between pre and post-therapy liver biopsies related to lipid metabolism and transport, inflammation and oxidative stress pathways. Conclusions: The combination of Avelumab plus ADC vaccine is safe and well tolerated but exhibited modest clinical activity. Our study describes, for the first-time, a de novo post-therapy metabolic rewiring, that could represent novel immunotherapy-induced tumor vulnerabilities.

Dendritic cells (DCs) are APCs essential in regulating the immune response. PGE₂, produced during inflammation, has a pivotal role in the maturation of DCs and, therefore, is vital for the immune response. The large variety of biologic functions governed by PGE₂ is mediated by its signaling through 4 distinct E-type prostanoid (EP) receptors. Immunogenic DCs express EP₂ and EP₄, which mediate the PGE₂ signaling. However, the expression and function of EP receptors in human tolerogenic DCs (tol-DCs), which present an inhibitory phenotype, have not yet, to our knowledge, been assessed. To clarify the role of EP receptors in tol-DCs, we examined the expression of different EP receptors and their effect using selective agonists in human cells. We find that EP₂ and EP₃ expression are up-regulated in in vitro–generated tol-DCs compared with mature DCs (mDCs). Activation of EP₂–EP₄ has a direct effect on the surface expression of costimulatory molecules and maturation receptors, such as CD80, CD83, and CD86 or MHCII and CCR7 in tol-DCs, the latter being exclusively modulated by PGE₂–EP₄ signaling. Importantly, we find that EP₂ and EP₃ receptors are involved in tolerance induction through IL-10 production by tol-DCs. These results are in sharp contrast with the inflammatory role of EP₄. Moreover, we show that DCs generated in the presence of agonists for EP receptors, induce naive T cell differentiation toward polarized Th1/Th17 cells. Given the differential effects of EP receptors, our results suggest that EP receptor agonist/antagonists might become relevant novel drug templates to modulate immune response.

Adoptive T cell therapy has successfully been implemented for the treatment of cancer. Nevertheless, ex vivo expansion of T cells by artificial antigen-presenting cells (aAPCs) remains cumbersome and can compromise T cell functionality, thereby limiting their therapeutic potential. We propose a radically different approach aimed at direct expansion of T cells in vivo, thereby omitting the need for large-scale ex vivo T cell production. We engineered nanosized immunofilaments (IFs), with a soluble semiflexible polyisocyanopeptide backbone that presents peptide-loaded major histocompatibility complexes and costimulatory molecules multivalently. IFs readily activated and expanded antigen-specific T cells like natural APCs, as evidenced by transcriptomic analyses of T cells. Upon intravenous injection, IFs reach the spleen and lymph nodes and induce antigen-specific T cell responses in vivo. Moreover, IFs display strong antitumor efficacy resulting in inhibition of the formation of melanoma metastases and reduction of primary tumor growth in synergy with immune checkpoint blockade. In conclusion, nanosized IFs represent a powerful modular platform for direct activation and expansion of antigen-specific T cells in vivo, which can greatly contribute to cancer immunotherapy.

During the last 20 years, chemotherapy has improved survival rates of colorectal cancer (CRC). However, the majority of metastatic cases do not respond to or progress after first line conventional chemotherapy and contribute to the fatalities of patients with CRC. Insights into the immune contexture of the tumor microenvironment (TME) have enabled the development of new systemic treatments that boost the host immune system against the tumor—the immune checkpoint inhibitors (ICI). These promising drugs have already shown astonishing efficacies in other cancer types and have raised new hope for the treatment of metastatic CRC (mCRC). In this review, we will summarize the results of the clinical trials that led to their accelerated approval by the U.S. Food and Drug Administration (FDA) in 2017, as well as all relevant recent studies conducted since then—some of which are not published yet. We will focus on therapeutic efficacy, but also discuss the available data for drug safety and security, changes in quality of life indicators and predictive biomarkers for treatment response. The burgeoning evidence for a potential use of ICIs in other settings than mCRC will also be mentioned. For each trial, we have made a preliminary assessment of the quality of clinical trial design and of the “European Society of Medical Oncology (ESMO) magnitude of clinical benefit” (ESMO-MCBS) in order to provide the first evidence-based recommendation to the reader.