Publications by authors named "Nathan Roth"

Article Synopsis
  • Ongoing research is essential for tracking and understanding the emergence of new SARS-CoV-2 variants, particularly as diagnostic testing declines in Australia during the COVID-19 pandemic.
  • In 2023, collaborations with pathology and genomics teams allowed for the monitoring of SARS-CoV-2 variants in New South Wales through various methods, including viral culture and analysis of immune responses from a large pool of blood donations.
  • Findings indicated that while existing antibodies generally neutralized many variants, specific mutations in emerging strains, particularly JN.1, suggested future challenges in controlling their spread due to enhanced transmissibility.
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Article Synopsis
  • The Omicron variant of COVID-19, which began in 2022, evolved from several lineages (BA.1, BA.2, BA.5) and developed mutations that help it evade neutralizing antibodies.
  • Researchers evaluated the effectiveness of antibody responses by tracking over 420,000 U.S. plasma donors and studying blood samples from vaccinated and recovered individuals, along with testing clinically approved therapies.
  • Findings indicated that antibody responses improved over time, but emerging variants like BQ.1.1 and XBF were increasingly resistant to treatments like Evusheld and Sotrovimab, suggesting that even dominant variants can evade antibodies while maintaining a persistent advantage in spreading.
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Background: Genetically distinct viral variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been recorded since January 2020. The introduction of global vaccine programs has contributed to lower COVID-19 hospitalisation and mortality rates, particularly in developed countries. In late 2021, Omicron BA.

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Background: COVID-19 convalescent plasma (CCP) was approved under emergency authorization to treat critically ill patients with COVID-19 in the United States in 2020. We explored the demographics of donors contributing plasma for a hyperimmune, plasma-derived therapy to evaluate factors that may be associated with anti-SARS-CoV-2 antibody response variability and, subsequently, antibody titers.

Study Design: An electronic search of CCP donors was performed across 282 US plasma donation centers.

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Genetically distinct variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have emerged since the start of the COVID-19 pandemic. Over this period, we developed a rapid platform (R-20) for viral isolation and characterization using primary remnant diagnostic swabs. This, combined with quarantine testing and genomics surveillance, enabled the rapid isolation and characterization of all major SARS-CoV-2 variants circulating in Australia in 2021.

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Analysis of convalescent plasma derived from individuals has shown that IgG3 has the most important role in binding to SARS-CoV-2 antigens; however, this has not yet been confirmed in large studies, and the link between binding and neutralization has not been confirmed. By analyzing plasma pools consisting of 247-567 individual convalescent donors, we demonstrated the binding of IgG3 and IgM to Spike-1 protein and the receptor-binding domain correlates strongly with viral neutralization in vitro. Furthermore, despite accounting for only approximately 12% of total immunoglobulin mass, collectively IgG3 and IgM account for approximately 80% of the total neutralization.

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Background: Plasma-derived intravenous immunoglobulin (IVIg) products contain a dynamic spectrum of immunoglobulin (Ig) G reactivities reflective of the donor population from which they are derived. We sought to model the concentration of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG which could be expected in future plasma pool and final-product batches of CSL Behring's immunoglobulin product Privigen.

Study Design And Methods: Data was extracted from accessible databases, including the incidence of coronavirus disease 2019 and SARS-CoV-2 vaccination status, antibody titre in convalescent and vaccinated groups and antibody half-life.

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The United States is currently affected by widespread hepatitis A virus (HAV) outbreaks. We investigated HAV incidence rates among source plasma donors in the United States since 2016. Serial donations from HAV-positive frequent donors were analyzed for common biologic markers to obtain a detailed picture of the course of infection.

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Despite the burgeoning field of coronavirus disease-19 (COVID-19) research, the persistence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralising antibodies remains unclear. This study validated two high-throughput immunological methods for use as surrogate live virus neutralisation assays and employed them to examine the half-life of SARS-CoV-2 neutralising antibodies in convalescent plasma donations made by 42 repeat donors between April and September 2020. SARS-CoV-2 neutralising antibody titres decreased over time but typically remained above the methods' diagnostic cut-offs.

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Background: Hepatitis E virus (HEV) is the leading cause of acute hepatitis throughout the world. Increasing blood component transfusion-associated HEV infections highlight the need for reliable virus inactivation procedures for plasma derivatives from pooled plasma donations.

Study Design And Methods: An animal infection study was conducted to evaluate the efficiency of HEV inactivation by pasteurization during the manufacturing process of the von Willebrand Factor/Factor VIII (VWF/FVIII) concentrate Haemate P/Humate-P (CSL Behring, Marburg, Germany).

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Comets contain primitive material leftover from the formation of the Solar System, making studies of their composition important for understanding the formation of volatile material in the early Solar System. This includes organic molecules, which, for the purpose of this review, we define as compounds with C-H and/or C-C bonds. In this review, we discuss the history and recent breakthroughs of the study of organic matter in comets, from simple organic molecules and photodissociation fragments to large macromolecular structures.

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Anion-exchange chromatography (AEX) is used in the downstream purification of monoclonal antibodies to remove impurities and potential viral contamination based on electrostatic interactions. Although the isoelectric point (pI) of viruses is considered a key factor predicting the virus adsorption to the resin, the precise molecular mechanisms involved remain unclear. To address this question, we compared structurally homologous parvoviruses that only differ in their surface charge distribution.

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Background: Nanofiltration entails the filtering of protein solutions through membranes with pores of nanometric sizes that have the capability to effectively retain a wide range of viruses.

Study Design And Methods: Data were collected from 754 virus validation studies (individual data points) by Plasma Protein Therapeutics Association member companies and analyzed for the capacity of a range of nanofilters to remove viruses with different physicochemical properties and sizes. Different plasma product intermediates were spiked with viruses and filtered through nanofilters with different pore sizes using either tangential or dead-end mode under constant pressure or constant flow.

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Background: Point-of-care ultrasound (PoCUS) by emergency physicians for renal colic has been proposed as an alternative to computed tomography (CT) to avoid ionizing radiation exposure and shorten emergency department length of stay. Previous studies have employed experienced or credentialed ultrasonographers or required advanced ultrasound skills. We sought to measure the diagnostic accuracy of PoCUS by physicians with varied experience using a simplified binary outcome of presence or absence of hydronephrosis.

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Recombinant protein therapeutics, vaccines, and plasma products have a long record of safety. However, the use of cell culture to produce recombinant proteins is still susceptible to contamination with viruses. These contaminations cost millions of dollars to recover from, can lead to patients not receiving therapies, and are very rare, which makes learning from past events difficult.

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Replacement therapy with plasma-derived C1-inhibitor (C1-INH) has been used for decades to treat patients with hereditary angioedema (HAE) with C1-INH deficiency. This article reviewed the rationale for using C1-INH replacement therapy in patients with HAE and the process of manufacturing plasma-derived C1-INH. The manufacture of C1-INH is an involved and carefully monitored process that includes screening and selection of prospective donors, the collection of source plasma, and purification with dedicated pathogen reduction steps.

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Different parvoviruses are used interchangeably as models in validation studies to demonstrate effective clearance of small viruses by filtration in the manufacturing of biotherapeutics. The aim of these experiments was to determine if filtration of different parvoviruses (canine parvovirus [CPV], minute virus of mice [MVM], and porcine parvovirus [PPV]) results in similar virus retention. While filtration with a Planova™ 20 N filter (mean pore size: 19 ± 2 nm) completely removed PPV and MVM from the filtrate (mean log reduction factors [LRFs] ≥5.

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Hepatitis E virus (HEV) is an emerging concern for the safety of plasma-derived medicinal products. The lack of an efficient cell culture system hampers the studies on HEV biology as well as validation studies to test the capacity of virus reduction steps to clear HEV. Hence, a surrogate hepevirus that can efficiently replicate in cell culture is needed.

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Background: Careful selection and testing of plasma reduces the risk of blood-borne viruses in the starting material for plasma-derived products. Furthermore, effective measures such as pasteurization at 60°C for 10 hours have been implemented in the manufacturing process of therapeutic plasma proteins such as human albumin, coagulation factors, immunoglobulins, and enzyme inhibitors to inactivate blood-borne viruses of concern. A comprehensive compilation of the virus reduction capacity of pasteurization is presented including the effect of stabilizers used to protect the therapeutic protein from modifications during heat treatment.

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Background: Hepatitis E virus (HEV) is a small, nonenveloped, single-stranded, RNA virus of emerging concern in industrialized countries. HEV transmission through transfusion of blood components has been reported, but not via plasma-derived medicinal products (PDMPs) manufactured with virus inactivation and/or removal steps. This study aimed to determine the prevalence of HEV among US source plasma donors.

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Alpha-proteinase inhibitor (API) deficiency is a genetic condition predisposing to emphysema. Respreeza/Zemaira, a therapeutic preparation of API, is prepared from human plasma. This article describes the purity and stability of Respreeza/Zemaira and the capacity of virus and prion reduction steps incorporated into its manufacturing process.

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Background: Beriplex P/N/Kcentra/Coaplex/Confidex is a four-factor human prothrombin complex concentrate (PCC). Here, we describe the pathogen safety profile and biochemical characteristics of an improved manufacturing process that further enhances the virus safety of Beriplex P/N.

Study Design And Methods: Samples of product intermediates were spiked with test viruses, and prions were evaluated under routine production and robustness conditions of the scale-down version of the commercial manufacturing process for their capacity to inactivate or remove pathogens.

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Objective: MicroRNAs are involved in many critical functions, including angiogenesis. Ultrasound-targeted microbubble destruction (UTMD) is a noninvasive technique for targeted vascular transfection of plasmid DNA and may be well suited for proangiogenic microRNA delivery. We aimed to investigate UTMD of miR-126-3p for therapeutic angiogenesis in chronic ischemia.

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