Development of an antibody cocktail for treatment of Sudan virus infection.

Antibody-based therapies are a promising treatment option for managing ebolavirus infections. Several Ebola virus (EBOV)-specific and, more recently, pan-ebolavirus antibody cocktails have been described. Here, we report the development and assessment of a Sudan virus (SUDV)-specific antibody cocktail. We produced a panel of SUDV glycoprotein (GP)-specific human chimeric monoclonal antibodies (mAbs) using both plant and mammalian expression systems and completed head-to-head in vitro and in vivo evaluations. Neutralizing activity, competitive binding groups, and epitope specificity of SUDV mAbs were defined before assessing protective efficacy of individual mAbs using a mouse model of SUDV infection. Of the mAbs tested, GP base-binding mAbs were more potent neutralizers and more protective than glycan cap- or mucin-like domain-binding mAbs. No significant difference was observed between plant and mammalian mAbs in any of our in vitro or in vivo evaluations. Based on in vitro and rodent testing, a combination of two SUDV-specific mAbs, one base binding (16F6) and one glycan cap binding (X10H2), was down-selected for assessment in a macaque model of SUDV infection. This cocktail, RIID F6-H2, provided protection from SUDV infection in rhesus macaques when administered at 50 mg/kg on days 4 and 6 postinfection. RIID F6-H2 is an effective postexposure SUDV therapy and provides a potential treatment option for managing human SUDV infection.

Pharmacokinetic Profiles of a Proposed Biosimilar Ustekinumab (BFI-751): Results From a Randomized Phase 1 Trial.

BioFactura has developed a proposed biosimilar candidate (BFI-751) to ustekinumab reference product. Results are reported for the first-in-human trial designed to compare the pharmacokinetic profiles, safety, and immunogenicity of BFI-751 and ustekinumab reference products from the European Union and United States as well as similarity of the EU and US reference products. This was a multicenter, randomized, double blind, 3-parallel-group study (trial ID: NCT04843631). Healthy subjects were randomized to receive a single subcutaneous dose of 45 mg of BFI-751, EU ustekinumab, or US ustekinumab. The pharmacokinetic parameters were area under the concentration-time curve (AUC) from time zero to infinity, AUC from time zero to the last quantifiable concentration, and maximum concentration. Safety, tolerability, and immunogenicity data were also reported. Pairwise comparisons among the 3 treatments all met the standard bioequivalence criteria that the 90% confidence interval of the geometric mean ratios of AUC from time zero to infinity, AUC from time zero to the last quantifiable concentration, and maximum concentration are completely within the acceptance interval of 80%-125%. There were no marked differences in the safety and tolerability profiles for subjects receiving BFI-751 as compared to EU or US ustekinumab. Treatment-emergent adverse events were mild to moderate for all treatment groups.

Attenuating nicotine's effects with high affinity human anti-nicotine monoclonal antibodies.

Use of nicotine-specific monoclonal antibodies (mAbs) to sequester and reduce nicotine distribution to brain has been proposed as a therapeutic approach to treat nicotine addiction (the basis of tobacco use disorder). A series of monoclonal antibodies with high affinity for nicotine (nic•mAbs) was isolated from B-cells of vaccinated smokers. Genes encoding 32 unique nicotine binding antibodies were cloned, and the mAbs expressed and tested by surface plasmon resonance to determine their affinity for S-(-)-nicotine. The highest affinity nic•mAbs had binding affinity constants (KD) between 5 and 67 nM. The 4 highest affinity nic•mAbs were selected to undergo additional secondary screening for antigen-specificity, protein properties (including aggregation and stability), and functional in vivo studies to evaluate their capacity for reducing nicotine distribution to brain in rats. The 2 most potent nic•mAbs in single-dose nicotine pharmacokinetic experiments were further tested in a dose-response in vivo study. The most potent lead, ATI-1013, was selected as the lead candidate based on the results of these studies. Pretreatment with 40 and 80 mg/kg ATI-1013 reduced brain nicotine levels by 56 and 95%, respectively, in a repeated nicotine dosing experiment simulating very heavy smoking. Nicotine self-administration was also significantly reduced in rats treated with ATI-1013. A pilot rat 30-day repeat-dose toxicology study (4x200mg/kg ATI-1013) in the presence of nicotine indicated no drug-related safety concerns. These data provide evidence that ATI-1013 could be a potential therapy for the treatment of nicotine addiction.

Experiments from unfinished Registered Reports in the Reproducibility Project: Cancer Biology.

As part of the Reproducibility Project: Cancer Biology, we published Registered Reports that described how we intended to replicate selected experiments from 29 high-impact preclinical cancer biology papers published between 2010 and 2012. Replication experiments were completed and Replication Studies reporting the results were submitted for 18 papers, of which 17 were accepted and published by eLife with the rejected paper posted as a preprint. Here, we report the status and outcomes obtained for the remaining 11 papers. Four papers initiated experimental work but were stopped without any experimental outcomes. Two papers resulted in incomplete outcomes due to unanticipated challenges when conducting the experiments. For the remaining five papers only some of the experiments were completed with the other experiments incomplete due to mundane technical or unanticipated methodological challenges. The experiments from these papers, along with the other experiments attempted as part of the Reproducibility Project: Cancer Biology, provides evidence about the challenges of repeating preclinical cancer biology experiments and the replicability of the completed experiments.

Lipid Nanoparticle Formulation Increases Efficiency of DNA-Vectored Vaccines/Immunoprophylaxis in Animals Including Transchromosomic Bovines.

The use of nucleic acid as a drug substance for vaccines and other gene-based medicines continues to evolve. Here, we have used a technology originally developed for mRNA in vivo delivery to enhance the immunogenicity of DNA vaccines. We demonstrate that neutralizing antibodies produced in rabbits and nonhuman primates injected with lipid nanoparticle (LNP)-formulated Andes virus or Zika virus DNA vaccines are elevated over unformulated vaccine. Using a plasmid encoding an anti-poxvirus monoclonal antibody (as a reporter of protein expression), we showed that improved immunogenicity is likely due to increased in vivo DNA delivery, resulting in more target protein. Specifically, after four days, up to 30 ng/mL of functional monoclonal antibody were detected in the serum of rabbits injected with the LNP-formulated DNA. We pragmatically applied the technology to the production of human neutralizing antibodies in a transchromosomic (Tc) bovine for use as a passive immunoprophylactic. Production of neutralizing antibody was increased by >10-fold while utilizing 10 times less DNA in the Tc bovine. This work provides a proof-of-concept that LNP formulation of DNA vaccines can be used to produce more potent active vaccines, passive countermeasures (e.g., Tc bovine), and as a means to produce more potent DNA-launched immunotherapies.

Bacterial-based systems for expression and purification of recombinant Lassa virus proteins of immunological relevance.

BACKGROUND: There is a significant requirement for the development and acquisition of reagents that will facilitate effective diagnosis, treatment, and prevention of Lassa fever. In this regard, recombinant Lassa virus (LASV) proteins may serve as valuable tools in diverse antiviral applications. Bacterial-based systems were engineered for expression and purification of recombinant LASV nucleoprotein (NP), glycoprotein 1 (GP1), and glycoprotein 2 (GP2). RESULTS: Full-length NP and the ectodomains of GP1 and GP2 were generated as maltose-binding protein (MBP) fusions in the Rosetta strains of Escherichia coli (E. coli) using pMAL-c2x vectors. Average fusion protein yields per liter of culture for MBP-NP, MBP-GP1, and MBP-GP2 were 10 mg, 9 mg, and 9 mg, respectively. Each protein was captured from cell lysates using amylose resin, cleaved with Factor Xa, and purified using size-exclusion chromatography (SEC). Fermentation cultures resulted in average yields per liter of 1.6 mg, 1.5 mg, and 0.7 mg of purified NP, GP1 and GP2, respectively. LASV-specific antibodies in human convalescent sera specifically detected each of the purified recombinant LASV proteins, highlighting their utility in diagnostic applications. In addition, mouse hyperimmune ascitic fluids (MHAF) against a panel of Old and New World arenaviruses demonstrated selective cross reactivity with LASV proteins in Western blot and enzyme-linked immunosorbent assay (ELISA). CONCLUSION: These results demonstrate the potential for developing broadly reactive immunological assays that employ all three arenaviral proteins individually and in combination.

Enhanced expression of a biosimilar monoclonal antibody with a novel NS0 platform.

The precise product quality and lower cost of goods demands of the growing biosimilars industry are driving biomanufacturing innovation. Biosimilar cell lines that produce complex glycoproteins such as monoclonal antibodies must be both highly productive and express a product with critical quality attributes closely matching those of the innovator reference. In this work, a biomanufacturing platform is described that harnesses the commercially-established NS0 host cell in new ways to create stable, highly productive cell lines with characteristics meeting the current demands. A cholesterol metabolic selection marker and implementation strategy that can be generically applied are shown to yield high expressing cell lines as well as eliminate the need for cholesterol addition, which has been a significant barrier in both stainless steel reactors as well as in single-use plastic systems. Additionally, for the first time, a multiplex selection strategy was implemented that served to increase NS0 cell line specific productivity >10-fold and volumetric yields >6-fold. The best overall performing cell line had a Qp of 28.5 picograms per cell per day and was rapidly adapted to a lean production medium. Yields in l-glutamine fed-batch shaker cultures exceeded 500 mg/L. An initial screening of four feeding strategies resulted in a final 13-day yield of over 1.4 g/L in small shaker culture. Overall, this work shows both the strategy to develop biosimilar cell lines and the commercial potential of a novel expression system highly suited for the manufacture of biosimilars of reference biologics currently produced in murine cells. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:455-462, 2018.

Intranasal monkeypox marmoset model: Prophylactic antibody treatment provides benefit against severe monkeypox virus disease.

Concerns regarding outbreaks of human monkeypox or the potential reintroduction of smallpox into an immunological naïve population have prompted the development of animal models and countermeasures. Here we present a marmoset model of monkeypox and smallpox disease utilizing a relevant poxvirus via a natural exposure route. We found that 1000 plaque forming units (PFU) of Monkeypox virus was sufficient to recapitulate smallpox disease, to include an incubation period of approximately 13 days, followed by the onset of rash, and death between 15 and 17 days. Temporally accurate manifestation of viremia and oral shedding were also features. The number of lesions ranged from no lesions to 299, the most reported in a marmoset exposed to a poxvirus. To both evaluate the efficacy of our antibodies and the applicability of the model system, marmosets were prophylactically treated with two monoclonal antibodies, c7D11 and c8A. Of three marmosets, two were completely free of disease and a single marmoset died 8 days after the mock (n = 1) or PBS control(s) (n = 2). Evaluation of the serum levels of the three animals provided a possible explanation to the animal succumbing to disease. Interestingly, more females had lesions (and a greater number of lesions) and lower viral burden (viremia and oral shedding) than males in our studies, suggesting a possible gender effect.

Replication Study: Melanoma genome sequencing reveals frequent PREX2 mutations.

In 2015, as part of the Reproducibility Project: Cancer Biology, we published a Registered Report (Chroscinski et al., 2014) that described how we intended to replicate selected experiments from the paper "Melanoma genome sequencing reveals frequent PREX2 mutations" (Berger et al., 2012). Here we report the results of those experiments. We regenerated cells stably expressing ectopic wild-type and mutant phosphatidylinositol-3,4,5-trisphosphate-dependent Rac exchange factor 2 (PREX2) using the same immortalized human NRASG12D melanocytes as the original study. Evaluation of PREX2 expression in these newly generated stable cells revealed varying levels of expression among the PREX2 isoforms, which was also observed in the stable cells made in the original study (Figure S6A; Berger et al., 2012). Additionally, ectopically expressed PREX2 was found to be at least 5 times above endogenous PREX2 expression. The monitoring of tumor formation of these stable cells in vivo resulted in no statistically significant difference in tumor-free survival driven by PREX2 variants, whereas the original study reported that these PREX2 mutations increased the rate of tumor incidence compared to controls (Figure 3B and S6B; Berger et al., 2012). Surprisingly, the median tumor-free survival was 1 week in this replication attempt, while 70% of the control mice were reported to be tumor-free after 9 weeks in the original study. The rapid tumor onset observed in this replication attempt, compared to the original study, makes the detection of accelerated tumor growth in PREX2 expressing NRASG12D melanocytes extremely difficult. Finally, we report meta-analyses for each result.

Registered report: tumour vascularization via endothelial differentiation of glioblastoma stem-like cells.

The Nature in 2010 (Ricci-Vitiani et al., 2010). The experiments that will be replicated are those reported in Figure 4B and Supplementary Figure 10B (Ricci-Vitiani et al., 2010), which demonstrate that glioblastoma stem-like cells can derive into endothelial cells, and can be selectively ablated to reduce tumor progression in vivo, and Supplementary Figures S10C and S10D (Ricci-Vitiani et al., 2010), which demonstrate that fully differentiated glioblastoma cells cannot form functionally relevant endothelium. The Reproducibility Project: Cancer Biology is a collaboration between the eLife.

Registered report: Melanoma genome sequencing reveals frequent PREX2 mutations.

The Reproducibility Project: Cancer Biology seeks to address growing concerns about reproducibility in scientific research by conducting replications of 50 papers in the field of cancer biology published between 2010 and 2012. This Registered Report describes the proposed replication plan of key experiments from "Melanoma genome sequencing reveals frequent PREX2 mutations" by Berger and colleagues, published in Nature in 2012 (Berger et al., 2012). The key experiments that will be replicated are those reported in Figure 3B and Supplementary Figure S6. In these experiments, Berger and colleagues show that somatic PREX2 mutations identified through whole-genome sequencing of human melanoma can contribute to enhanced lethality of tumor xenografts in nude mice (Figure 3B, S6B, and S6C; Berger et al., 2012). The Reproducibility Project: Cancer Biology is a collaboration between the Center for Open Science and Science Exchange, and the results of the replications will be published by eLife.

Lassa fever in post-conflict sierra leone.

BACKGROUND: Lassa fever (LF), an often-fatal hemorrhagic disease caused by Lassa virus (LASV), is a major public health threat in West Africa. When the violent civil conflict in Sierra Leone (1991 to 2002) ended, an international consortium assisted in restoration of the LF program at Kenema Government Hospital (KGH) in an area with the world's highest incidence of the disease. METHODOLOGY/PRINCIPAL FINDINGS: Clinical and laboratory records of patients presenting to the KGH Lassa Ward in the post-conflict period were organized electronically. Recombinant antigen-based LF immunoassays were used to assess LASV antigenemia and LASV-specific antibodies in patients who met criteria for suspected LF. KGH has been reestablished as a center for LF treatment and research, with over 500 suspected cases now presenting yearly. Higher case fatality rates (CFRs) in LF patients were observed compared to studies conducted prior to the civil conflict. Different criteria for defining LF stages and differences in sensitivity of assays likely account for these differences. The highest incidence of LF in Sierra Leone was observed during the dry season. LF cases were observed in ten of Sierra Leone's thirteen districts, with numerous cases from outside the traditional endemic zone. Deaths in patients presenting with LASV antigenemia were skewed towards individuals less than 29 years of age. Women self-reporting as pregnant were significantly overrepresented among LASV antigenemic patients. The CFR of ribavirin-treated patients presenting early in acute infection was lower than in untreated subjects. CONCLUSIONS/SIGNIFICANCE: Lassa fever remains a major public health threat in Sierra Leone. Outreach activities should expand because LF may be more widespread in Sierra Leone than previously recognized. Enhanced case finding to ensure rapid diagnosis and treatment is imperative to reduce mortality. Even with ribavirin treatment, there was a high rate of fatalities underscoring the need to develop more effective and/or supplemental treatments for LF.

Integrated biofabrication for electro-addressed in-film bioprocessing.

Many recent advances in bioprocessing have been enabled by developments in miniaturization and microfluidics. A continuing challenge, however, is integrating multiple unit operations that require distinct spatial boundaries, especially with included labile biological components. We have suggested "biofabrication" as a means for organizing cells and biomolecules in complex configurations while preserving function of individual components. Polysaccharide films of chitosan and alginate that are assembled on-chip by electrodeposition are "smart" configurable interfaces that mediate communication between the biological systems and microfabricated devices. Here, we demonstrate the scalable performance of a production address, where incubated cells secrete antibodies, and a capture address, where secreted antibody is retained with specificity and subsequently assayed. The antibody exchange from one electro-address to another exemplifies integrated in-film bioprocessing, facilitated by the integrated biofabrication techniques used. This in-film approach enables complex processes without need for microfluidics and valving. Finally, we have shown scalability by reducing electrode sizes to a 1 mm scale without compromising film biofabrication or bioprocessing performance. The in situ reversible deposition of viable cells, productivity characterization, and capture of secreted antibodies could find use in bioprocessing applications such as clonal selection, run-to-run monitoring, initial scale-up, and areas including drug screening and biopsy analysis.

Scalable purification of Bacillus anthracis protective antigen from Escherichia coli.

The anthrax toxin consists of three proteins, protective antigen (PA), lethal factor, and edema factor that are produced by the Gram-positive bacterium, Bacillus anthracis. Current vaccines against anthrax use PA as their primary component. In this study, we developed a scalable process to produce and purify multi-gram quantities of highly pure, recombinant PA (rPA) from Escherichia coli. The rPA protein was produced in a 50-L fermentor and purified to >99% purity using anion-exchange, hydrophobic interaction, and hydroxyapatite chromatography. The final yield of purified rPA from medium cell density fermentations resulted in approximately 2.7 g of rPA per kg of cell paste (approximately 270 mg/L) of highly pure, biologically active rPA protein. The results presented here exhibit the ability to generate multi-gram quantities of rPA from E. coli that may be used for the development of new anthrax vaccines and anthrax therapeutics.