Biocatalytic Method for Producing an Affinity Resin for the Isolation of Immunoglobulins.

Affinity chromatography is a widely used technique for antibody isolation. This article presents the successful synthesis of a novel affinity resin with a mutant form of protein A (BsrtA) immobilized on it as a ligand. The key aspect of the described process is the biocatalytic immobilization of the ligand onto the matrix using the sortase A enzyme. Moreover, we used a matrix with primary amino groups without modification, which greatly simplifies the synthesis process. The resulting resin shows a high dynamic binding capacity (up to 50 mg IgG per 1 mL of sorbent). It also demonstrates high tolerance to 0.1 M NaOH treatment and maintains its effectiveness even after 100 binding, elution, and sanitization cycles.

Development and characterization of anti-SARS-CoV-2 intravenous immunoglobulin from COVID-19 convalescent plasma.

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.

An intravenous immunoglobulin with a high concentration of SARS-CoV-2-neutralizing antibodies was prepared from COVID-19 convalescent plasma, which could be utilized as a passive immunization tool in regard to COVID-19 treatment. The manufacturing process employed conforms to commonly held business standards within the intravenous immunoglobulin industry and includes plasma ethanol fractionation following chromatographic purification and special virus removal or inactivation steps. The results of the preclinical in vitro and in vivo experiments demonstrate that the immunoglobulin produced in this study is pure and safe enough to be considered for intravenous applications. The SARS-CoV-2 neutralizing antibody concentration was found to have increased 9.4 ± 1.4-times compared with human plasma. The anti-COVID-19 hyperimmune immunoglobulin showed no signs of toxicity and did not cause any blood clot formations when administered to rabbits. Furthermore, the anti-COVID-19 hyperimmune immunoglobulin was demonstrated to protect immunosuppressed hamsters against SARS-CoV-2.

Two-Step Size-Exclusion Nanofiltration of Prothrombin Complex Concentrate Using Nanocellulose-Based Filter Paper.

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.