Paolo Macor

Therapeutic cancer vaccines have been proposed to stimulate an immune response for controlling disease progression and reducing treatment recurrence in cancer, such as pancreatic ductal adenocarcinoma (PDAC). Here, we proposed the use of PLGA/PVA nanoparticles (NPs) as the delivery component of a vaccine constituted by a chimeric protein composed of glypican-1 (GPC1) associated with flagellin (FL) from Salmonella typhi (GPC1-FL) for PDAC treatment. Subcutaneous and oral vaccination protocols were performed in a PDAC syngeneic mouse model with GPC1-FL PLGA/PVA NPs. In a syngeneic mouse model of human GPC1-expressing PDAC, we showed evidence of immunogenicity of GPC1-FL being capable of eliciting a specific anti-GPC1 IgG antibody response when subcutaneously administered. Moreover, we demonstrated that the use of PLGA/PVA NPs to encapsulate GPC1-FL is capable of increasing immunogenicity of the formulation, as demonstrated by the higher anti-GPC1 IgG titer, also associated with mouse survival increase. Finally, we demonstrated both in vitro and in vivo that the PLGA/PVA NPs are able to protect GPC1-FL during gastrointestinal transit and promote its delivery to the intestinal immune system after oral administration. PLGA/PVA NPs could act as the delivery component of an effective vaccine formulation against GPC1 that could be useful for PDAC treatment.

Objectives: The Certified Reference Material (CRM) ERM ^® -DA477/IFCC is a new polyclonal IgG anti-beta2-glycoprotein I (anti-β2GPI) material for the harmonization of the laboratory diagnosis of antiphospholipid syndrome (APS). We evaluated CRM’s ability to represent the heterogeneity of APS patient anti-β2GPI antibodies and to calibrate IgG anti-β2GPI methods. Methods: We characterized CRM for its reactivity against domain-1, using the QUANTA Flash ^® β2GPI-domain-1 assay, and against domains-4-5 of β2GPI, and single-domain-deleted β2GPI molecules using in-house ELISAs. We used QUANTA Lite ^® ELISA, QUANTA Flash ^® CLIA, and EliA™ FEIA methods to evaluate the CRM’s anti-Cardiolipin (anti-CL) activity. Four anti-β2GPI IgG methods (in-house and QUANTA Lite ^® ELISA, QUANTA Flash ^® CLIA, and EliA™ FEIA) were also used to evaluate the CRM’s calibration efficacy, alongside 133 clinical samples (CSs) and 99 controls. Results: The CRM showed high anti-domain-1 activity and no anti-domain-4-5 activity at the recommended assay dilution. The domain-dependent-β2GPI reactivity profiles were comparable with full-blown APS. There was acceptable dilution linearity for anti-CL assays with R ² ranging from 0.957 to 0.997. For the four anti-β2GPI IgG assays, calibration with the CRM led to a good comparability of the average result of CSs for two of the assays. New cut-offs calculated from this work improved comparability in quantitative results between three of the assays: 85 % concordance with CRM compared to 66 % concordance with assay-specific-calibration. Conclusions: The CRM is representative of patient anti-β2GPI/CL heterogeneity and should improve anti-β2GPI IgG method harmonization. However, the level of achievable method harmonization is affected by differences in the selectivity among the assays.

Introduction: The functionalization of nanoparticles (NPs) with an antiCD19 targeting mechanism represents a promising approach for the selective delivery of drugs and nucleic acids into normal and tumor B cells. This strategy has the advantage of minimizing off-target effects by restricting gene delivery to the desired cell population. However, the nanoplatform must guarantee both the local production of the protein and the safety of the treatment to allow an effective therapy with reduced systemic toxicity.Methods: In order to ensure a selective delivery of nucleic acids, we developed poly(lactic-co-glycolic acid) (PLGA)-poly(vinyl alcohol) (PVA) NPs loaded with an Enhanced Green Fluorescent Protein (EGFP)-coding plasmid and covalently coated with antiCD19 recombinant antibody as a targeting mechanism. To assess the functionality of the NPs, physicochemical characterization, safety tests, and transfection assay were employed to evaluate the NPs’ behavior in vitro and in vivo, in a human/zebrafish lymphoma xenograft model.Results: The results demonstrated that the PLGA-PVA nanoplatform was capable of efficiently encapsulating and releasing the payload. These nanostructures demonstrated a favorable safety profile, as evidenced by the absence of significant cell cytotoxicity, coagulation activation, complement system activation, and the slight activation of endothelial cells and leukocytes. The targeting mechanism facilitated the interaction of NPs with target cells, thereby enhancing their internalization and subsequent exogenous plasmid DNA (pDNA) translation and protein expression. In the human/zebrafish lymphoma xenograft model, no evidence of toxicity was observed, and targeted NPs demonstrated the capacity to enhance exogenous pDNA expression.Conclusion: Our findings provide a rationale for the use of targeted NPs as a DNA delivery system for the local expression of therapeutic proteins.

Proline-rich antimicrobial peptides (PrAMPs) have gained attention due to their antimicrobial properties and low cytotoxicity. B7-005, a small optimized PrAMP, exhibits a broader spectrum of activity than native PrAMPs, due to an antimicrobial mechanism based on inhibiting prokaryotic protein synthesis and destabilizing bacterial membranes. However, the toxicity and the in vivo efficacy of B7-005 remain poorly understood, so in vitro and in vivo microbiology and toxicology experiments were used to assess its suitability as an anti-infective agent. The incidence of resistance towards B7-005 by E. coli was lower than for other PrAMPs and antibiotics; moreover, it maintained antimicrobial activity in the presence of human serum. B7-005 exerted its antimicrobial effect at a much lower concentration than those causing harmful effects on four different cell types, such as membrane permeabilization or non-lytic depolarization of mitochondria. The latter effect may be related to the inhibition of eukaryotic protein synthesis by B7-005 observed in vitro . In a zebrafish embryo model, B7-005 was well tolerated and reduced mortality from pre-existing E. coli bacteraemia. Overall, B7-005 was safe for human cells and effective against systemic infection in vivo , making it a promising lead for developing new antibiotics.

Purpose: In the bloodstream, nanoparticles (NPs) interact with serum proteins to form the protein corona, which includes both opsonins, promoting NP recognition and elimination, and dysopsonins, which can inhibit opsonin activity. Albumin, the most abundant serum protein, is part of this corona and can act as a dysopsonin, potentially hiding NPs from the immune system. This study aims to investigate how a covalently bound layer of human serum albumin (HSA) on polymeric NPs affects the protein corona and their behavior in the immune system. Methods: We covalently attached HSA to the surface of polymeric NPs to modify the protein corona composition. These HSA-covered nanostructures were then decorated with an anti-CD19 recombinant antibody fragment to target malignant B cells, specifically acute lymphoblastic leukemia (ALL) cells. The safety profile and bioavailability of these targeted HSA-nanoparticles were evaluated in vitro and in vivo using a human-zebrafish xenograft model of ALL. The efficacy of the nanostructures in delivering encapsulated doxorubicin and suppressing tumor growth was also assessed. Results: The HSA coating on polymeric NPs effectively modified the protein corona, preventing opsonization and subsequent macrophage-mediated elimination. The targeted HSA-nanoparticles maintained a safe profile with reduced macrophage interaction and specifically targeted tumor cells in the xenograft model. This resulted in the successful delivery of doxorubicin, tumor growth suppression, and increased survival of the model organisms. Conclusion: The study demonstrates that HSA-coated nanoparticles can be used as a therapeutic nanoplatform with a safe profile and enhanced bioavailability. The ability to decorate these nanostructures with specific targeting agents, such as anti-CD19 antibodies, opens up the potential for developing versatile therapeutic platforms that can be tailored to target various clinical conditions.

The complement system is a pivotal component of innate immunity, extensively studied in vertebrates but also present in invertebrates. This study explores the existence of a terminal complement pathway in the tunicate Botryllus schlosseri, aiming to understand the evolutionary integration of innate and adaptive immunity. Through transcriptome analysis, we identified a novel transcript, BsITCCP, encoding a protein with both MACPF and LDLa domains—a structure resembling that of vertebrate C9 but with a simpler organization. Phylogenetic reconstruction positions BsITCCP between invertebrate perforins and vertebrate terminal complement proteins, suggesting an evolutionary link. Localization studies confirmed that bsitccp is transcribed in cytotoxic morula cells (MCs), which are also responsible for producing other complement components like BsC3, BsMBL, BsMASP, and BsBf. Functional assays demonstrated that bsitccp transcription is upregulated in response to nonself challenges and is dependent on BsC3 activity; inhibition of BsC3 led to a significant reduction in BsITCCP expression. Electron microscopy revealed that MCs form contact with perforated yeast cells, indicating a possible mechanism of cell lysis similar to the immunological synapse observed in vertebrates. These findings suggest that a C3-governed lytic complement pathway exists in B. schlosseri, challenging the assumption that a C5 ortholog is necessary for such a pathway. This work enhances our understanding of the evolution of the complement system and suggests that invertebrates possess a terminal complement complex capable of mediating cell lysis, regulated by C3. Future studies will focus on confirming the pore-forming ability of BsITCCP and its role in the immunological synapse.

Background: Nanoparticles represent one of the most important innovations in the medical field. Among nanocarriers, polymeric nanoparticles (PNPs) attracted much attention due to their biodegradability, biocompatibility, and capacity to increase efficacy and safety of encapsulated drugs. Another important improvement in the use of nanoparticles as delivery systems is the conjugation of a targeting agent that enables the nanoparticles to accumulate in a specific tissue. Despite these advantages, the clinical translation of therapeutic approaches based on nanoparticles is prevented by their interactions with blood proteins. In fact, the so-formed protein corona (PC) drastically alters the biological identity of the particles. Adsorbed activated proteins of the complement cascade play a pivotal role in the clearance of nanoparticles, making them more easily recognized by macrophages, leading to their rapid elimination from the bloodstream and limiting their efficacy. Since the mouse is the most used preclinical model for human disease, this work compared human and mouse PC formed on untargeted PNPs (uPNPs) and targeted PNPs (tPNPs), paying particular attention to complement activation. Results: Mouse and human serum proteins adsorbed differently to PNPs. The differences in the binding of mouse complement proteins are minimal, whereas human complement components strongly distinguish the two particles. This is probably due to the human origin of the Fc portion of the antibody used as targeting agent on tPNPs. tPNPs and uPNPs mainly activate complement via the classical and alternative pathways, respectively, but this pattern did not affect their binding and internalization in macrophages and only a limited consumption of the activity of the human complement system was documented. Conclusions: The results clearly indicate the presence of complement proteins on PNPs surface but partially derived from an unspecific deposition rather than an effective complement activation. The presence of a targeting antibody favors the activation of the classical pathway, but its absence allows an increased activation of the alternative pathway. This results in similar opsonization of both PNPs and similar phagocytosis by macrophages, without an impairment of the activity of circulating complement system and, consequently, not enhancing the susceptibility to infection. Graphical

Antibody-Drug Conjugates (ADCs) represent an innovative class of potent anti-cancer compounds that are widely used in the treatment of hematologic malignancies and solid tumors. Unlike conventional chemotherapeutic drug-based therapies, that are mainly associated with modest specificity and therapeutic benefit, the three key components that form an ADC (a monoclonal antibody bound to a cytotoxic drug via a chemical linker moiety) achieve remarkable improvement in terms of targeted killing of cancer cells and, while sparing healthy tissues, a reduction in systemic side effects caused by off-tumor toxicity. Based on their beneficial mechanism of action, 15 ADCs have been approved to date by the market approval by the Food and Drug Administration (FDA), the European Medicines Agency (EMA) and/or other international governmental agencies for use in clinical oncology, and hundreds are undergoing evaluation in the preclinical and clinical phases. Here, our aim is to provide a comprehensive overview of the key features revolving around ADC therapeutic strategy including their structural and targeting properties, mechanism of action, the role of the tumor microenvironment and review the approved ADCs in clinical oncology, providing discussion regarding their toxicity profile, clinical manifestations and use in novel combination therapies. Finally, we briefly review ADCs in other pathological contexts and provide key information regarding ADC manufacturing and analytical characterization.