Nanoplastics are pervasive environmental contaminants that continuously expose humans and accumulate in multiple organs. Increasing evidence associates NPs with adverse health effects, including inflammation and carcinogenesis, yet their impact on human innate and adaptive immunity remains poorly understood. This knowledge gap is particularly relevant for diseases treated with therapies that modulate immune responses. Here, we investigated the effects of NP exposure on major subsets of human peripheral lymphocytes, essential for antitumor and antiviral defense while preserving immune tolerance. Peripheral blood mononuclear cells from healthy donors were exposed to oxidized and plasma-exposed NPs, which acquired a stable protein corona. NP exposure induced a time-dependent increase in immune cell interactions and resulted in reduced activation and functionality of CD4⁺ and CD8⁺ T cells, B cells, and natural killer cells. T lymphocytes displayed impaired tumor antigen-specific responses, while natural killer cells showed decreased tumor cell-killing capacity. Notably, B cells internalized NPs, leading to reduced ability to generate antibodies against SARS-CoV-2. Overall, these findings demonstrate that NPs compromise both innate and adaptive immune functions, weakening antiviral and antitumor responses. Our results highlight potential risks associated with NP exposure for susceptibility to infections and cancer as well as immune-based therapy efficacy.

Abstract Background Bacterial toxins are emerging as promising hallmarks of colorectal cancer (CRC) pathogenesis. In particular, Cytotoxic Necrotizing Factor 1 (CNF1) from E. coli deserves special consideration due to the significantly higher prevalence of this toxin gene in CRC patients with respect to healthy subjects, and to the numerous tumor-promoting effects that have been ascribed to the toxin in vitro. Despite this evidence, a definitive causal link between CNF1 and CRC was missing. Here we investigated whether CNF1 plays an active role in CRC onset by analyzing pro-carcinogenic key effects specifically induced by the toxin in vitro and in vivo. Methods Viability assays, confocal microscopy of γH2AX and 53BP1 molecules and cytogenetic analysis were carried out to assess CNF1-induced genotoxicity on non-neoplastic intestinal epithelial cells. Caco-2 monolayers and 3D Caco-2 spheroids were used to evaluate permeability alterations specifically induced by CNF1, either in the presence or in the absence of inflammation. In vivo, an inflammatory bowel disease (IBD) model was exploited to evaluate the carcinogenic potential of CNF1. Immunohistochemistry and immunofluorescence stainings of formalin-fixed paraffin-embedded (FFPE) colon tissue were carried out as well as fecal microbiota composition analysis by 16 S rRNA gene sequencing. Results CNF1 induces the release of reactive oxidizing species and chromosomal instability in non-neoplastic intestinal epithelial cells. In addition, CNF1 modifies intestinal permeability by directly altering tight junctions’ distribution in 2D Caco-2 monolayers, and by hindering the differentiation of 3D Caco-2 spheroids with an irregular arrangement of these junctions. In vivo, repeated intrarectal administration of CNF1 induces the formation of dysplastic aberrant crypt foci (ACF), and produces the formation of colorectal adenomas in an IBD model. These effects are accompanied by the increased neutrophilic infiltration in colonic tissue, by a mixed pro-inflammatory and anti-inflammatory cytokine milieu, and by the pro-tumoral modulation of the fecal microbiota. Conclusions Taken together, our results support the hypothesis that the CNF1 toxin from E. coli plays an active role in colorectal carcinogenesis. Altogether, these findings not only add new knowledge to the contribution of bacterial toxins to CRC, but also pave the way to the implementation of current screening programs and preventive strategies.

Background: Breast cancer represents one of the leading causes of death among women. Surgery can be effective, but once breast cancer has metastasized, it becomes extremely difficult to treat. Conventional therapies are associated with substantial toxicity and poor efficacy due to tumor heterogeneity, treatment resistance and disease relapse. Moreover, immune checkpoint blockade appears to offer limited benefit in breast cancer. The poor tumor immunogenicity and the immunosuppressive tumor microenvironment result in scarce T-cell infiltration, leading to a low response rate. Thus, there is considerable interest in the development of improved active immunotherapies capable of sensitizing a patient’s immune system against tumor cells. Methods: We evaluated the in vitro anti-tumor activity of a personalized vaccine based on dendritic cells generated in the presence of interferon (IFN)-α and granulocyte-macrophage colony-stimulating factor (IFN-DC) and loaded with an oxidized lysate from autologous tumor cells expanded as 3D organoid culture maintaining faithful tumor antigenic profiles. Results: Our findings demonstrate that stimulation of breast cancer patients’ lymphocytes with autologous IFN-DC led to efficient Th1-biased response and the generation in vitro of potent cytotoxic activity toward the patients’ own tumor cells. Conclusions: This approach can be potentially applied in association with checkpoint blockade and chemotherapy in the design of new combinatorial therapies for breast cancer.

CT-PET scan showing clinical response of Pt#3

Supplementary Table I: IFN-DC release criteria and median values registered among patient-derived IFN-DC (min-max range); Supplementary Table 2: Patients MHC-I and MHC-II alleles and IGHV epitope sequences

CT-PET scan showing clinical response of Pt#2.

Immunotherapy with immune checkpoint inhibitors (ICIs) has revolutionized cancer treatment providing unprecedented clinical benefits. However, many patients do not respond to ICIs as monotherapy or develop resistance. Combining ICI-based immunotherapy with chemotherapy is a promising strategy to increase response rates, but few rationale-driven chemo-immunotherapy combinations have reached the clinical arena thus far. In the present study, we show that combined anti-PDL1 and anti-PDL2 antibodies optimally synergize with cyclophosphamide but not with cisplatin, and that the magnitude and duration of the therapeutic response is dependent on the immunogenic potential of the drug and of the tumor itself. Hallmarks of successful therapeutic outcomes were the enhanced infiltration by myeloid (mainly cross-presenting dendritic cells, eosinophils, and monocytic myeloid cells) and T lymphocytes into the tumor tissue and the expansion of circulating memory pools. Overall, our results suggest that immunomodulating chemotherapy can be exploited to increase the efficacy of PD1/PDL axis inhibitors in vivo, and that the magnitude of the synergic therapeutic response is affected by tumor-intrinsic immunogenicity.

Purpose: This study was aimed at evaluating the feasibility, safety, immunological and clinical responses in patients with Follicular lymphoma (FL) treated with monocyte-derived dendritic cells generated in the presence of interferon-alpha and GM-CSF (IFN-DC) in combination with low doses of Rituximab (R). Experimental design: Firstly, we analyzed in vitro and in vivo the immunological properties of IFN-DC against FL. Thus, we performed a phase I trial in 8 refractory and relapsed FL patients based on sequential intranodal injections of low-dose of R and unloaded IFN-DC and report the safety, clinical and immunological results of the enrolled patients. Results: Preclinical studies indicated that IFN-DC can synergize with R leading to increased cytotoxicity and T cell tumor infiltration. The clinical evaluation showed that the combined treatment was totally safe. The overall response rate was 50%, PET-negative complete response rate 37% and remission is still ongoing in 2/4 of responding patients (median follow- up 26 months, range 11-47). Notably, following the combined therapy all patients showed induction/enhancement of T cell responses by CD107 degranulation or IFN-g ELISPOT assay against patient-specific tumor IGHV sequences. Conclusions: These results represent the proof-of-principle on the effectiveness of unloaded IFN-DC in inducing durable clinical responses and promoting induction of tumor specific peripheral T cells, thus suggesting the occurrence of an effective endogenous antitumor vaccination. The overall findings indicate that some unique properties of IFN-DC can be successfully exploited to induce/enhance antitumor responses, thus representing a valuable antitumor strategy for novel and more effective combination therapies in cancer patients. Translational relevance: The development of protocols of in situ cancer immunotherapy aimed at inducing an endogenous vaccination is currently regarded as a practical and promising antitumor strategy, with potential advantages with respect to the use of defined tumor antigens for inducing a broader antitumor immunity, potentially targeting also neoantigens emerging during tumor progression and therapies. This study represents the first evidence on the safety and clinical effectiveness of IFN-DC, a unique type of DC rapidly generated from monocytes under simple GMP conditions and endowed with special immunostimulatory properties. Combined with low doses of intranodal injection of R, IFN-DC induced clinical response in cancer patients and promoted the induction of tumor specific T cells. All this implies the occurrence of an endogenous antitumor vaccination possibly resulting in clinical response. The findings suggest that IFN-DC are a good candidate for a selective clinical use in combination therapies in cancer patients Keywords: dendritic cells; follicular lymphoma (FL); immune system.

AbstractPurpose: This study was aimed at evaluating the feasibility, safety, immunologic and clinical responses in patients with follicular lymphoma treated with monocyte-derived dendritic cells generated in the presence of IFNα and GM-CSF (IFN-DC) in combination with low doses of rituximab. Patients and Methods: Firstly, we analyzed in vitro and in vivo the immunologic properties of IFN-DC against follicular lymphoma. Thus, we performed a phase I trial in 8 patients with refractory and relapsed follicular lymphoma based on sequential intranodal injections of low-dose of rituximab and unloaded IFN-DC and report the safety, clinical, and immunologic results of the enrolled patients. Results: Preclinical studies indicated that IFN-DC can synergize with rituximab leading to increased cytotoxicity and T-cell tumor infiltration. The clinical evaluation showed that the combined treatment was totally safe. The overall response rate was 50%, PET-negative complete response rate 37%, and remission is still ongoing in 2/4 of responding patients (median follow-up 26 months, range 11–47). Notably, following the combined therapy all patients showed induction/enhancement of T-cell responses by CD107 degranulation or IFNγ ELISPOT assay against patient-specific tumor IGHV sequences. Conclusions: These results represent the proof-of-principle on the effectiveness of unloaded IFN-DC in inducing durable clinical responses and promoting induction of tumor-specific peripheral T cells, thus suggesting the occurrence of an effective endogenous antitumor vaccination. The overall findings indicate that some unique properties of IFN-DC can be successfully exploited to induce/enhance antitumor responses, thus representing a valuable antitumor strategy for novel and more effective combination therapies in patients with cancer.

The perspective of combining cancer vaccines with immunomodulatory drugs is currently regarded as a highly promising approach for boosting tumor-specific T cell immunity and eradicating residual malignant cells. The efficacy of dendritic cell (DC) vaccination in combination with lenalidomide, an anticancer drug effective in several hematologic malignancies, was investigated in a follicular lymphoma (FL) model. First, we evaluated the in vitro activity of lenalidomide in modulating the immune responses of lymphocytes co-cultured with a new DC subset differentiated with IFN-α (IFN-DC) and loaded with apoptotic lymphoma cells. We next evaluated the efficacy of lenalidomide and IFN-DC-based vaccination, either alone or in combination, in hu-PBL-NOD/SCID mice bearing established human lymphoma. We found that lenalidomide reduced Treg frequency and IL-10 production in vitro, improved the formation of immune synapses of CD8 + lymphocytes with lymphoma cells and enhanced anti-lymphoma cytotoxicity. Treatment of lymphoma-bearing mice with either IFN-DC vaccination or lenalidomide led to a significant decrease in tumor growth and lymphoma cell spread. Lenalidomide treatment was shown to substantially inhibit tumor-induced neo-angiogenesis rather than to exert a direct cytotoxic effect on lymphoma cells. Notably, the combined treatment with the vaccine plus lenalidomide was more effective than either single treatment, resulting in the significant regression of established tumors and delayed tumor regrowth upon treatment discontinuation. In conclusion, our data demonstrate that IFN-DC-based vaccination plus lenalidomide exert an additive therapeutic effect in xenochimeric mice bearing established lymphoma. These results may pave the way to evaluate this combination in the clinical ground.

Although promising, the clinical benefit provided by dendritic cell (DC)-based vaccines is still limited and the choice of the optimal antigen formulation is still an unresolved issue. We have developed a new DC-based vaccination protocol for aggressive and/or refractory lymphomas which combines the unique features of interferon-conditioned DC (IFN-DC) with highly immunogenic tumor cell lysates (TCL) obtained from lymphoma cells undergoing immunogenic cell death. We show that treatment of mantle cell lymphoma (MCL) and diffuse large B-cell lymphoma (DLBCL) cell lines with 9-cis-retinoic acid and IFNα (RA/IFNα) induces early membrane exposure of Calreticulin, HSP70 and 90 together with CD47 down-regulation and enhanced HMGB1 secretion. Consistently, RA/IFNα-treated apoptotic cells and -TCLs were more efficiently phagocytosed by DCs compared to controls. Notably, cytotoxic T cells (CTLs) generated with autologous DCs pulsed with RA/IFNα-TCLs more efficiently recognized and specifically lysed MCL or DLBCL cells or targets loaded with several HLA-A*0201 cyclin D1 or HLA-B*0801 survivin epitopes. These cultures also showed an expansion of Th1 and Th17 cells and an increased Th17/Treg ratio. Moreover, DCs loaded with RA/IFNα-TCLs showed enhanced functional maturation and activation. NOD/SCID mice reconstituted with human peripheral blood lymphocytes and vaccinated with autologous RA/IFNα-TCL loaded-IFN-DCs showed lymphoma-specific T-cell responses and a significant decrease in tumor growth with respect to mice treated with IFN-DC unpulsed or loaded with untreated TCLs. This study demonstrates the feasibility and efficacy of the use of RA/IFNα to generate a highly immunogenic TCL as a suitable tumor antigen formulation for the development of effective anticancer DC-based vaccines.

AuNP and AuNP/DXM stability and drug release kinetics in different biological media.

Abstract INTRODUCTION Follicular lymphoma (FL) is considered a chronic, immune responsive and still incurable tumour. Recently two papers have shown the efficacy of active immunotherapy by repeated administration of autologous dendritic cells (DC) in Follicular Lymphoma (FL). Notably, in both studies a third of patients achieved long lasting remission. A novel DC population (IFN-DC), differentiated from human monocytes in the presence of GM-CSF and IFN-alpha has been developed in the laboratory of the Istituto Superiore di Sanità (ISS). IFN-DC have been demonstrated highly efficient in internalizing tumour-cell antigens, recovering "in vitro" T-cell responses from FL patients, as well as in mediating NK cell activation and enhanced cytotoxic effector function toward autologous FL cells. We have recently started a phase I study (approved by EC in 2014, EudraCT: 2013-003158-25) of intranodal immunotherapy based on sequential injection of low-dose anti-CD20 antibody (Ab) and IFN-D, in patients with advanced FL. Here we report early results of the ongoing trial. STUDY DESIGN IFN-DC Trial (EudraCT: 2013-003158-25) is a phase I trial aiming at evaluating safety and tolerability as well as immune and clinical responses of a IFN-DC based therapy in combination with rituximab for the treatment of patients with advanced FL. · The Primary endpoints are: I) Evaluation of safety and tolerability of treatment II) Evaluation of tumor-specific immune responses. by determining: i) Tumor-specific immune response in peripheral blood; ii) Intratumoral infiltration of immune cells; iii) DTH test. · The secondary endpoint is clinical response. The study population consists of patients with relapsed/refractory FL, aged 18-75 years, not needing immediate retreatment basing on the GELF Criteria. The · Treatment: the regimen foresees eight injection cycles, each consisting of the combined administration of rituximab and IFN-DC. The first four administered every two-weeks and the remaining four administered monthly. Rituximab (5-10mg) and low or high doses of IFN-DC (20±5 x106 or 40±5x106cells respectively), are administered by intranodal direct injection (IDI). RESULTS Five patients have been enrolled so far. The treatment proved to be safe, feasible and well tolerated. Three patients have completed treatment and two experienced complete remission with disappearance of both proximal and distal lesions, as confirmed by PET scan. Notably in both patients the distal lymph nodes, which had not been directly treated by intranodal injections, reduced to normal size earlier than those treated by IDI (abscopal effect). One of these two is still in durable complete clinical and molecular remission after 17 months while the latter patient, who had progressed after completing eight cycles of treatment, experienced a complete clinical remission after a second course of immunotherapy ( Fig.1). Two out of three patients performed the DHT test and, despite one of the two achieved remission, they both resulted non-responsive. The characterization of IFN-DC and lymphoma nodes in FL patients have shown high expression of PD-1 and PD-L1 in FL microenvironment and on IFN-DC respectively. Immunomonitoring is currently underway. However, quantification of NF-kB (p65) nuclear translocation by multispectral image flow cytometry, as a marker of NK cell activation, showed the persistence of higher percentages of activated NK cells in the two responding patients (Fig.2). CONCLUSION Currently no definitive data prove the benefit of IDI treatment, however the trial is ongoing and other patients are under screening. Notably both the responding patients showed the abscopal effect. The possible set-up of an effective and comparatively economic treatment, that exploits patients' immune system against this chronic and immune responsive tumour, is worth of exploring. Furthermore it can be envisaged that the combination of immune checkpoint inhibitor antibodies to DC-based therapies, might improve clinical activity of DC-based strategies. Disclosures No relevant conflicts of interest to declare.

Follicular lymphoma (FL) is the most common form of indolent non-Hodgkin lymphoma. This malignancy is considered virtually incurable, with high response rates to therapy but frequent relapses. We investigated the ability of monocyte-derived dendritic cells generated in the presence of IFN-α and GM-CSF (IFN-DC) and loaded with apoptotic lymphoma cells to activate immune responses against FL cells, with the ultimate goal of designing novel patient-specific vaccination strategies for the treatment of FL. In this article, we show that apoptotic tumor cell-loaded IFN-DC from FL patients, which were cultured for 2 wk with autologous lymphocytes, led to Th1 response skewing, based on significantly higher levels of IFN-γ production and a remarkable increase in CD8(+) and NK cell frequency, consistent with the detection of enhanced cytotoxic effector function toward autologous FL cells. IFN-DC were found to promote efficient NK cell activation, increased expression of cytotoxicity receptors, and extensive IFN-γ production in the virtual absence of IL-10. Moreover, direct recognition and killing of primary autologous lymphoma cells by activated NK cells from FL patients was also demonstrated. A critical role was demonstrated for MHC class I-related chain A and B and membrane-bound IL-15 in IFN-DC-mediated NK cell activation and early IFN-γ production. The overall results indicate that IFN-DC loaded with autologous apoptotic FL cells represent a valuable tool for improving the potency of therapeutic cancer vaccines through the efficient induction of NK cell activation and promotion of CD8(+) T cell antitumor immunity.

Cross-presentation allows antigen-presenting cells to present exogenous antigens to CD8(+) T cells, playing an essential role in controlling infections and tumor development. IFN-α induces the rapid differentiation of human mono-cytes into dendritic cells, known as IFN-DCs, highly efficient in mediating cross-presentation, as well as the cross-priming of CD8(+) T cells. Here, we have investigated the mechanisms underlying the cross-presentation ability of IFN-DCs by studying the intracellular sorting of soluble ovalbumin and nonstructural-3 protein of hepatitis C virus. Our results demonstrate that, independently from the route and mechanism of antigen entry, IFN-DCs are extraordinarily competent in preserving internalized proteins from early degradation and in routing antigens toward the MHC class-I processing pathway, allowing long-lasting, cross-priming capacity. In IFN-DCs, both early and recycling endosomes function as key compartments for the storage of both antigens and MHC-class I molecules and for proteasome- and transporter-associated with Ag processing-dependent auxiliary cross-presentation pathways. Because IFN-DCs closely resemble human DCs naturally occurring in vivo in response to infections and other danger signals, these findings may have important implications for the design of vaccination strategies in neoplastic or chronic infectious diseases.

IFN-α exerts multiple effects leading to immune protection against pathogens and cancer as well to autoimmune reactions by acting on monocytes and dendritic cells. We analyzed the versatility of human monocytes conditioned by IFN-α towards dendritic cell differentiation (IFN-DC) in shaping the autologous T-helper response. Priming of naïve CD4 T cells with autologous IFN-DC in the presence of either SEA or anti-CD3, resulted, in addition to a prominent expansion of CXCR3+ IFN-γ-producing CD4 Th1 cells, in the emergence of two distinct subsets of IL-17-producing CD4 T cells: i) a predominant Th17 population selectively producing IL-17 and expressing CCR6; ii) a minor Th1/Th17 population, producing both IL-17 and IFN-γ. After phagocytosis of apoptotic cells, IFN-DC induced Th17 cell expansion and IL-17 release. Notably, the use of neutralizing antibodies revealed that IL-23 was an essential cytokine in mediating Th17 cell development by IFN-DC. The demonstration of the IFN-DC-induced expansion of both Th1 and Th17 cell populations reveals the intrinsic plasticity of these DC in orienting the immune response and provides a mechanistic link between IFN-α and the onset of autoimmune phenomena, which have been correlated with both IL-17 production and exposure to IFN-α.

Virus-like particles (VLPs) are excellent tools for vaccines against pathogens and tumors. They can accommodate foreign polypeptides whose incorporation efficiency and immunogenicity however decrease strongly with the increase of their size. We recently described the CD8+ T cell immune response against a small foreign antigen (i.e., the 98 amino acid long human papilloma virus E7 protein) incorporated in human immunodeficiency virus (HIV)-1 based VLPs as product of fusion with an HIV-1 Nef mutant (Nefmut). Here, we extended our previous investigations by testing the antigenic/immunogenic properties of Nefmut-based VLPs incorporating much larger heterologous products, i.e., human hepatitis C virus (HCV) NS3 and influenza virus NP proteins, which are composed of 630 and 498 amino acids, respectively. We observed a remarkable cross-presentation of HCV NS3 in dendritic cells challenged with Nefmut–NS3 VLPs, as detected using a NS3 specific CD8+ T cell clone as well as PBMCs from HCV infected patients. On the other hand, when injected in mice, Nefmut–NP VLPs elicited strong anti-NP CD8+ T cell and CTL immune responses. In addition, we revealed the ability of Nefmut incorporated in VLPs to activate and mature primary human immature dendritic cells (iDCs). This phenomenon correlated with the activation of Src tyrosine kinase-related intracellular signaling, and can be transmitted from VLP-challenged to bystander iDCs. Overall, these results prove that Nefmut-based VLPs represent a rather flexible platform for the design of innovative CD8+ T cell vaccines.

Here we report a novel strategy for the induction of CD8+ T cell adaptive immune response against viral and tumor antigens. This approach relies on high levels of incorporation in HIV-1 VLPs of a mutant of HIV-1 Nef (Nefmut) which can act as anchoring element for foreign proteins. By in vitro assay, we found that VLP-associated Nefmut is efficiently cross-presented by antigen presenting cells. Inoculation in mice of VLPs incorporating the HPV-16 E7 protein fused to Nefmut led to an anti-E7 CD8+ T cell response much stronger than that elicited by E7 recombinant protein inoculated with incomplete Freund's adjuvant and correlating with well-detectable anti-E7 CTL activity. Most relevantly, mice immunized with Nefmut-E7 VLPs developed a protective immune response against tumors induced by E7 expressing tumor cells. These results make Nefmut VLPs a promising candidate for new vaccine strategies focused on the induction of CD8+ T cell immunity.