SARS-CoV-2 antigen-carrying extracellular vesicles activate T cell responses in a human immunogenicity model.

Extracellular vesicles (EVs) are entering the clinical arena as novel biologics for infectious diseases, potentially serving as the immunogenic components of next generation vaccines. However, relevant human assays to evaluate the immunogenicity of EVs carrying viral antigens are lacking, contributing to challenges in translating rodent studies to human clinical trials. Here, we engineered EVs to carry SARS-CoV-2 Spike to evaluate the immunogenicity of antigen-carrying EVs using human peripheral blood mononuclear cells (PBMCs). Delivery of Spike EVs to PBMCs resulted in specific immune cell activation as assessed through T cell activation marker expression. Further, Spike EVs were taken up largely by antigen-presenting cells (monocytes, dendritic cells and B cells). Taken together, this human PBMC-based system models physiologically relevant pathways of antigen delivery, uptake and presentation. In summary, the current study highlights the suitability of using human PBMCs for evaluating the immunogenicity of EVs engineered to carry antigens for infectious disease therapeutics.

A clinically relevant large-scale biomanufacturing workflow to produce natural killer cells and natural killer cell-derived extracellular vesicles for cancer immunotherapy.

Natural killer cell-derived extracellular vesicles (NK-EVs) have shown promising potential as biotherapeutics for cancer due to their unique attributes as cytotoxic nanovesicles against cancer cells and immune-modulatory activity towards immune cells. However, a biomanufacturing workflow is needed to produce clinical-grade NK-EVs for pre-clinical and clinical applications. This study established a novel biomanufacturing workflow using a closed-loop hollow-fibre bioreactor to continuously produce NK-EVs from the clinically relevant NK92-MI cell line under serum-free, Xeno-free and feeder-free conditions following GMP-compliant conditions. The NK92 cells grown in the bioreactor for three continuous production lots resulted in large quantities of both NK cell and NK-EV biotherapeutics at the end of each production lot (over 109 viable cells and 1013 EVs), while retaining their cytotoxic payload (granzyme B and perforin), pro-inflammatory cytokine (interferon-gamma) content and cytotoxicity against the human leukemic cell line K562 with limited off-target toxicity against healthy human fibroblast cells. This scalable biomanufacturing workflow has the potential to facilitate the clinical translation of adoptive NK cell-based and NK-EV-based immunotherapies for cancer with GMP considerations.

Effects of Copper or Zinc Organometallics on Cytotoxicity, DNA Damage and Epigenetic Changes in the HC-04 Human Liver Cell Line.

Copper and zinc organometallics have multiple applications and many are considered "data-poor" because the available toxicological information is insufficient for comprehensive health risk assessments. To gain insight into the chemical prioritization and potential structure activity relationship, the current work compares the in vitro toxicity of nine "data-poor" chemicals to five structurally related chemicals and to positive DNA damage inducers (4-nitroquinoline-oxide, aflatoxin-B1). The HC-04 non-cancer human liver cell line was used to investigate the concentration-response effects (24 h and 72 h exposure) on cell proliferation, DNA damage (γH2AX and DNA unwinding assays), and epigenetic effects (global genome changes in DNA methylation and histone modifications using flow cytometry). The 24 h exposure screening data (DNA abundance and damage) suggest a toxicity hierarchy, starting with copper dimethyldithiocarbamate (CDMDC, CAS#137-29-1) > zinc diethyldithiocarbamate (ZDEDC, CAS#14324-55-1) > benzenediazonium, 4-chloro-2-nitro-, and tetrachlorozincate(2-) (2:1) (BDCN4CZ, CAS#14263-89-9); the other chemicals were less toxic and had alternate ranking positions depending on assays. The potency of CDMDC for inducing DNA damage was close to that of the human hepatocarcinogen aflatoxin-B1. Further investigation using sodium-DMDC (SDMDC, CAS#128-04-1), CDMDC and copper demonstrated the role of the interactions between copper and the DMDC organic moiety in generating a high level of CDMDC toxicity. In contrast, additive interactions were not observed with respect to the DNA methylation flow cytometry data in 72 h exposure experiments. They revealed chemical-specific effects, with hypo and hypermethylation induced by copper chloride (CuCl2, CAS#10125-13-0) and zinc-DMDC (ZDMDC, CAS#137-30-4), respectively, but did not show any significant effect of CDMDC or SDMDC. Histone-3 hypoacetylation was a sensitive flow cytometry marker of 24 h exposure to CDMDC. This study can provide insights regarding the prioritization of chemicals for future study, with the aim being to mitigate chemical hazards.

Specific location of galactosylation in an afucosylated antiviral monoclonal antibody affects its FcγRIIIA binding affinity.

Monoclonal antibodies (mAbs) comprise an essential type of biologic therapeutics and are used to treat diseases because of their anti-cancer and anti-inflammatory properties, and their ability to protect against respiratory infections. Its production involves post-translational glycosylation, a biosynthetic process that conjugates glycans to proteins, which plays crucial roles in mAb bioactivities including effector functions and pharmacokinetics. These glycans are heterogeneous and have diverse chemical structures whose composition is sensitive to manufacturing conditions, rendering the understanding of how specific glycan structures affect mAb bioactivity challenging. There is a need to delineate the effects of specific glycans on mAb bioactivity to determine whether changes in certain glycosylation profiles (that can occur during manufacturing) will significantly affect product quality. Using enzymatic transglycosylation with chemically-defined N-glycans, we show that galactosylation at a specific location of N-glycans in an afucosylated anti-viral mAb is responsible for FcγRIIIA binding and antibody-dependent cell-mediated cytotoxicity (ADCC) activity. We report a facile method to obtain purified asymmetric mono-galactosylated biantennary complex N-glycans, and their influence on bioactivity upon incorporation into an afucosylated mAb. Using ELISA, surface plasmon resonance and flow cytometry, we show that galactosylation of the α6 antenna, but not the α3 antenna, consistently increases FcγRIIIA binding affinity. We confirm its relevance in an anti-viral model of respiratory syncytial virus (RSV) using an adapted ADCC reporter assay. We further correlate this structure-function relationship to the interaction of the galactose residue of the α6 antenna with the protein backbone using 2D-1H-15N-NMR, which showed that galactosylation of at this location exhibited chemical shift perturbations compared to glycoforms lacking this galactose residue. Our results highlight the importance of identifying and quantifying specific glycan isomers to ensure adequate quality control in batch-to-batch and biosimilar comparisons.

Ozone-dependent increases in lung glucocorticoids and macrophage response: Effect modification by innate stress axis function.

Although considerable inter-individual variability exists in health effects associated with air pollutant exposure, underlying reasons remain unclear. We examined whether innate differences in stress axis function modify lung glucocorticoid and macrophage responses to ozone (O3). Highly-stress responsive Fischer (F344) and less responsive Lewis (LEW) rats were exposed for 4 h by nose-only inhalation to air or O3 (0.8 ppm). Ozone increased corticosterone recovered by bronchoalveolar lavage in both strains (F344 > LEW). Higher corticosterone in F344 was associated with a blunted response to O3 of macrophage pro-inflammatory genes compared to LEW. Pharmacological inhibition of O3-dependent corticosterone production in F344 enhanced the inflammatory gene response to O3, mimicking the LEW phenotype. Examination of potential impacts of glucocorticoids on macrophage function using a human monocyte-derived macrophage cell line (THP-1) showed that cortisol modified phagocytosis in a macrophage phenotype-dependent manner. Overall, our data implicate endogenous glucocorticoids in the regulation of pulmonary macrophage responses to O3.

Hollow-fiber bioreactor production of extracellular vesicles from human bone marrow mesenchymal stromal cells yields nanovesicles that mirrors the immuno-modulatory antigenic signature of the producer cell.

BACKGROUND: Extracellular vesicles (EVs) produced by human bone marrow-derived mesenchymal stromal cells (hBM-MSCs) are currently investigated for their clinical effectiveness towards immune-mediated diseases. The large amounts of stem cell-derived EVs required for clinical testing suggest that bioreactor production systems may be a more amenable alternative than conventional EV production methods for manufacturing products for therapeutic use in humans. METHODS: To characterize the potential utility of these systems, EVs from four hBM-MSC donors were produced independently using a hollow-fiber bioreactor system under a cGMP-compliant procedure. EVs were harvested and characterized for size, concentration, immunophenotype, and glycan profile at three separate intervals throughout a 25-day period. RESULTS: Bioreactor-inoculated hBM-MSCs maintained high viability and retained their trilineage mesoderm differentiation capability while still expressing MSC-associated markers upon retrieval. EVs collected from the four hBM-MSC donors showed consistency in size and concentration in addition to presenting a consistent surface glycan profile. EV surface immunophenotypic analyses revealed a consistent low immunogenicity profile in addition to the presence of immuno-regulatory CD40 antigen. EV cargo analysis for biomarkers of immune regulation showed a high abundance of immuno-regulatory and angiogenic factors VEGF-A and IL-8. CONCLUSIONS: Significantly, EVs from hBM-MSCs with immuno-regulatory constituents were generated in a large-scale system over a long production period and could be frequently harvested with the same quality and quantity, which will circumvent the challenge for clinical application.

Highly sensitive magnetic-microparticle-based aptasensor for Cryptosporidium parvum oocyst detection in river water and wastewater: Effect of truncation on aptamer affinity.

Many methods have been reported to detect Cryptosporidium parvum (C. parvum) oocysts in the water environment using monoclonal antibodies. Herein, we report the use of DNA aptamers as an alternative ligand. We present the highly sensitive detection of C. parvum oocysts in wastewater samples based on aptamer-conjugated magnetic beads. A previously selected DNA aptamer (R4-6) that binds to C. parvum oocysts with high affinity and selectivity was rationally truncated into two minimer aptamers (Min_Crypto1 and Min_Crypto2), and conjugated to micro-magnetic beads. In flow cytometry tests with phosphate buffer, river water, and wastewater samples, both the minimers showed improved affinity and specificity toward C. parvum oocysts than the parent R4-6. Moreover, Min_Crypto2 showed higher affinity to its target than the parent aptamer when testing in wastewater, indicating superior binding properties in a complex matrix. Using a fluorescence microplate-based assay, and when incubated with different numbers of oocysts, Min_Crypto2 showed a limit of detection as low as 5 C. parvum oocysts in 300 µL of wastewater. Results described here indicate that Min_Crypto2 has superior specificity and sensitivity for the detection of C. parvum oocysts, and has a strong potential to be used successfully in a sensor.

A comprehensive proteomics profiling identifies NRP1 as a novel identity marker of human bone marrow mesenchymal stromal cell-derived small extracellular vesicles.

BACKGROUND: Clinical applications have shown extracellular vesicles (EVs) to be a major paracrine effector in therapeutic responses produced by human mesenchymal stromal/stem cells (hMSCs). As the regenerative capacity of EVs is mainly ascribed to the transfer of proteins and RNA composing its cargo, and to the activity attributed by the protein surface markers, we sought to profile the protein composition of small EVs released from hMSCs to identify hMSC-EV biomarkers with potential clinical relevance. METHODS: Small EVs were produced and qualified from five human bone marrow MSC donors at low passage following a 48-h culture in exosome-depleted medium further processed by steps of centrifugation, filtration, and precipitation. Quantitative proteomic analysis comparing the protein profile of the EVs released from hMSCs and their parental cell was conducted using tandem mass tag labeling combined to mass spectrometry (LC-MS/MS) to identify enriched EV protein markers. RESULTS: Nanoparticle tracking analysis showed no differences in the EV concentration and size among the five hMSC donors (1.83 × 1010 ± 3.23 × 109/mL), with the mode particle size measuring at 109.3 ± 5.7 nm. Transmission electron microscopy confirmed the presence of nanovesicles with bilayer membranes. Flow cytometric analysis identified commonly found exosomal (CD63/CD81) and hMSC (CD105/CD44/CD146) markers from released EVs in addition to surface mediators of migration (CD29 and MCSP). Quantitative proteomic identified 270 proteins significantly enriched by at least twofold in EVs released from hMSCs as compared to parental hMSCs, where neuropilin 1 (NRP1) was identified among 21 membrane-bound proteins regulating the migration and invasion of cells, as well as chemotaxis and vasculogenesis. Validation by western blot of multiple batches of EVs confirmed consistent enrichment of NRP1 in the nanovesicles released from all five hMSC donors. CONCLUSION: The identification and verification of NRP1 as a novel enriched surface marker from multiple batches of EVs derived from multiple hMSC donors may serve as a biomarker for the assessment and measurement of EVs for therapeutic uses.

Integrin α4ß7 expression on peripheral blood CD4+ T cells predicts HIV acquisition and disease progression outcomes.

The gastrointestinal (GI) mucosa is central to HIV pathogenesis, and the integrin α4ß7 promotes the homing of immune cells to this site, including those that serve as viral targets. Data from simian immunodeficiency virus (SIV) animal models suggest that α4ß7 blockade provides prophylactic and therapeutic benefits. We show that pre-HIV infection frequencies of α4ß7+ peripheral blood CD4+ T cells, independent of other T cell phenotypes and genital inflammation, were associated with increased rates of HIV acquisition in South African women. A similar acquisition effect was observed in a Kenyan cohort and in nonhuman primates (NHPs) after intravaginal SIV challenge. This association was stronger when infection was caused by HIV strains containing V2 envelope motifs with a preference for α4ß7 binding. In addition, pre-HIV α4ß7+ CD4+ T cells predicted a higher set-point viral load and a greater than twofold increased rate of CD4+ T cell decline. These results were confirmed in SIV-infected NHPs. Increased frequencies of pre-HIV α4ß7+ CD4+ T cells were also associated with higher postinfection expression of lipopolysaccharide binding protein, a microbial translocation marker, suggestive of more extensive gut damage. CD4+ T cells expressing α4ß7 were rapidly depleted very early in HIV infection, particularly from the GI mucosa, and were not restored by early antiretroviral therapy. This study provides a link between α4ß7 expression and HIV clinical outcomes in humans, in line with observations made in NHPs. Given the availability of a clinically approved anti-α4ß7 monoclonal antibody for treatment of inflammatory bowel disease, these data support further evaluation of targeting α4ß7 integrin as a clinical intervention during HIV infection.

Elevated expression of LAG-3, but not PD-1, is associated with impaired iNKT cytokine production during chronic HIV-1 infection and treatment.

BACKGROUND: LAG-3 is a potent negative regulator of the immune response but its impact in HIV infection in poorly understood. Unlike exhaustion markers such as PD-1, Tim-3, 2B4 and CD160, LAG-3 is poorly expressed on bulk and antigen-specific T cells during chronic HIV infection and its expression on innate lymphocyte subsets is not well understood. The aim of this study was to assess LAG-3 expression and association with cellular dysfunction on T cells, NK cells and iNKT cells among a cohort of healthy and HIV-infected female sex workers in Nairobi, Kenya. RESULTS: Ex vivo LAG-3 expression was measured by multiparametric flow cytometry, and plasma cytokine/chemokine concentrations measured by bead array. Although LAG-3 expression on bulk T cells was significantly increased among HIV-infected women, the proportion of cells expressing the marker was extremely low. In contrast, LAG-3 was more highly expressed on NK and iNKT cells and was not reduced among women treated with ART. To assess the functional impact of LAG-3 on iNKT cells, iNKT cytokine production was measured in response to lipid (αGalCer) and PMA/Io stimulation by both flow cytometry and cytokine bead array. iNKT cytokine production is profoundly altered by both HIV infection and treatment, and LAG-3, but not PD-1, expression is associated with a reduction in iNKT IFNγ production. CONCLUSIONS: LAG-3 does not appear to mediate T cell exhaustion in this African population, but is instead expressed on innate lymphocyte subsets including iNKT cells. HIV infection alters iNKT cytokine production patterns and LAG-3 expression is uniquely associated with iNKT dysfunction. The continued expression of LAG-3 during treatment suggests it may contribute to the lack of innate immune reconstitution commonly observed during ART.

Enrichment of LAG-3, but not PD-1, on double negative T cells at the female genital tract.

PROBLEM: The expression of inhibitory markers such as LAG-3 and PD-1 on T lymphocytes regulates immune function. Their expression at the genital mucosa is poorly understood, but regulation of immune activation at the female genital tract likely controls susceptibility to sexually transmitted infections. METHOD OF STUDY: Cervical mononuclear cells were phenotyped by flow cytometry. Concentrations of cytokines were determined in cervical-vaginal lavage samples by bead array. RESULTS: LAG-3 expression was significantly elevated at the genital mucosa and was associated with expression of CCR5 and CD69. Double negative (DN) T cells expressed the highest levels of LAG-3, but not PD-1, and were more activated than other T lymphocytes. CONCLUSION: The elevated expression of LAG-3 at the genital tract suggests it may regulate T-cell activation, and identify cells susceptible to HIV infection. The enrichment of LAG-3 on DN T cells suggests LAG-3 may contribute to the immunoregulatory activity of these cells.

Amyotrophic lateral sclerosis in Olmsted County, Minnesota, 1925 to 1998.

The authors sought to determine trends in the incidence of ALS in Olmsted County from 1925 to 1998. Seventy-seven cases of ALS were identified during the period studied. The incidence rate remained stable at 1.7 cases per 100,000 people per year. Mean age at onset was 63 years. Mean survival was 23 months from diagnosis. Mean survival for patients <60 years old was 31 months; for patients aged >or=60 years, it was 20 months (p = 0.02). Mean time from symptom onset to diagnosis was 13 months. Neither survival nor time to diagnosis changed significantly over time.