Coagulation Factor IX-rich protrhombin complex concentrate (FIX-PCC) is a therapeutic biologic product that consists of a mixture of several human plasma-derived proteins, useful for treating hemophilia B. Due to its complex composition, FIX-PCC is very challenging to bioprocess through virus removing nanofilters in order to ensure its biosafety. This article describes a two-step filtration process of FIX-PCC using a nanocellulose-based filter paper with tailored porosity. The filters were characterized with scanning electron microscopy (SEM), cryoporometry with differential scanning calorimetry, and nitrogen gas sorption. Furthermore, in order to probe the filter’s cut-off size rejection threshold, removal of small- and large-size model viruses, i.e., ΦX174 (28 nm) and PR772 (70 nm), was evaluated. The feed, pre-filtrate, and permeate solutions were characterized with mass-spectrometric proteomic analysis, dynamic light scattering (DLS), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and analytical size-exclusion high-performance liquid chromatography (SEHPLC). By sequential filtration through 11 μm pre-filter and 33 μm virus removal filter paper, it was possible to achieve high product throughput and high virus removal capacity. The presented approach could potentially be applied for bioprocessing other protein-based drugs.

Background: The authors describe the developmental process of intravenous anti-COVID-19 hyperimmune immunoglobulin from anti-SARS-CoV-2 neutralizing antibody-containing plasma. Furthermore, the authors investigated its safety and protective activity in animal models. Materials & methods: The manufacturing process included standard ethanol fractionation, chromatographic purification steps and virus removal or inactivation. Results: The authors produced pure and safe immunoglobulin for intravenous administration, with 98.1 ± 6.5 mg/ml protein content, of which 97.6 ± 0.7% was IgG. The concentration factor of SARS-CoV-2 neutralizing antibodies was 9.4 ± 1.4-times. Safety studies in animals showed no signs of acute/chronic toxicity or allergenic or thrombogenic properties. Intravenous anti-COVID-19 hyperimmune immunoglobulin protected immunosuppressed hamsters against SARS-Cov-2. Conclusion: The obtained results can allow the start of clinical trials to study the safety and efficacy in healthy adults.

Introduction. Using of immunoglobulins containing SARS-CoV-2 neutralizing antibodies may be an effective and safe tool for COVID-19 treatment. An intravenous immunoglobulin COVID-globulin from donor blood plasma containing SARS-CoV-2 neutralizing antibodies was developed at Joint-Stock Company Nacimbio.Aim. A pilot study of the safety of the "COVID-globulin".Materials and methods. When studying the safety of the preparation in animals the following parameters were evaluated: general toxicity, thrombogenic potential, influence on hematological and biochemical parameters, blood clotting and hemolytic activity, determination of local irritant action, pyrogenic properties, bacterial endotoxins, allergic effect of the drug preparation and its physicochemical characteristics.Results and discussion. Safety studies of "COVID-globulin" in animals showed no signs of intoxication, local irritant action and thrombogenic properties. Macroscopic and histological examination of the organs of rats treated with COVID-globulin showed no signs of necrosis, inflammation, atypia, or any significant pathological changes. Hematological and biochemical parameters of the blood of laboratory animals after the administration of "COVID-globulin" corresponded to the reference values. Administration of COVID-globulin to rabbits did not activate blood clot formation. The IgG subclasses distribution in the preparation corresponded to that in human plasma. The activity of the Fc-function of the immunoglobulin molecule was more than 130 % compared to the reference standard preparation, the concentration of the prekallikrein activator in the COVID-globulin ranged from 4.2 to 4.8 IU/ml, anticomplementary activity was less than 1 unit complement per 1 mg of protein.Conclusion. The results of all studies have demonstrated a high level of safety of the developed COVID-globulin preparation, which meets the safety requirements for human immunoglobulins for intravenous administration by national regulatory documents and the European Pharmacopoeia.

A method for determination of a non-methylated deoxycytidine (dC) residue in the recognition site of 5-cytosine DNA-methyltransferases is suggested. The method is based on treatment of methylated DNA by sodium bisulfite and successive reaction of the thus modified DNA with a repair enzyme, uracil-DNA glycosylase. This method was successfully applied to identify NlaX methyltransferase specificity.

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