Recombinant plasma proteins

Advances and challenges in the purification of recombinant coagulation factors: A review

Hemostasis is a complex process for the cessation of bleeding from an injured blood vessel, involving the interplay of 12 coagulation factors in the coagulation cascade with activated blood platelets and the vessel wall. Hence, the coagulation factors are important to control hemorrhage. However, the low abundance of many coagulation factors in human plasma proteins limited their production in therapeutic drugs and their clinical applications. With the development of modern biotechnology, commercially manufactured recombinant coagulation factors became available as hemostatic therapeutics, emerging a huge potential in pharmaceutical manufacturing market. Unlike antibodies, whose standard operation unit or platform purification processes in the industrial-scale downstream processing has been well-established, the complexity in post-translational modification and differences in structures of the coagulation factors posed specific challenges with respect to the downstream processing, which have long been limiting their industrial-scale production. This review presents a comprehensive overview of the technological development of commercially manufactured recombinant coagulation factors, with emphasis on their advances and challenges in the separation and purification processes. Firstly, the licensed products of the plasma derived and recombinant coagulation factors are summarized. Then, typical recombinant coagulation factors, i.e. factors VII, VIII and IX, are introduced with detailed discussion on their preparative separation procedures for both the licensed products of industrial-scale and the experimental cases of laboratory-scale. Finally, perspectives and challenges in the future development of the purification technology of recombinant coagulation factors are highlighted to provide new insight into the design of cost-effective purification processes of recombinant coagulation factors.

Extraction of plasmid DNA by use of a magnetic maghemite-polyaniline nanocomposite

We describe the use of a hybrid magnetic nanocomposite (HMNC) for the extraction and purification of plasmid DNA (pDNA) from Escherichia coli aqueous solutions. The HMNC, which was synthesized via emulsion polymerization, was characterized by transmission electron microscopy, scanning electron microscopy, UV-Vis spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering and magnetic measurements. The results confirmed the incorporation of polyaniline (Pani) in its conducting form onto a core formed by the magnetic iron oxide, with the hybrid particles presenting an average size of (95 ± 30) nm and a saturation magnetization of 30 emu/g. The yield, purity and quality of the pDNA purified by using the Pani HMNC were evaluated by UV-Vis spectroscopy, agarose gel electrophoresis, and Polymerase Chain Reaction (PCR), respectively. An average yield of ~6.9 μg was obtained in the DNA extraction process, with the collected material presenting a good purity (a ₳260/280 ratio in the 1.68-1.82 range) and an excellent quality, as confirmed by subsequent PCR assays. Hence, this HMNC appears as a promising material for use in pDNA purification protocols, and we suggest that this novel HMNC-based methodology can be of general interest and find widespread application in different biomedical procedures.

Eptacog beta: a novel recombinant human factor VIIa for the treatment of hemophilia A and B with inhibitors

INTRODUCTION

Hemophilia A and B are X-linked recessive disorders caused by the deficiency of factor VIII or factor IX, respectively. Bleeding episodes are treated with factor replacement therapy. The most serious complication of this treatment is the development of inhibitors. In such patients, bypassing agents, such as activated recombinant human factor VII (rhFVIIa) or plasma-derived activated prothrombin complex concentrates, are administered to prevent or treat bleeding episodes. The high cost of the current bypassing agents limits their availability in emerging countries. Areas covered: Authors reviewed the published data on the development and clinical testing of eptacog beta, a new second-generation rhFVIIa produced in the milk of transgenic rabbits. The available data indicate that activated eptacog beta exhibits structural (N- and O- glycosylation), pharmacodynamic and pharmacokinetic characteristics similar to activated eptacog alfa, its main competitor, but binds slightly better to platelets and HUVEC, and it is safe and effective. Expert commentary: This critical review of available data on activated eptacog beta shows that it represents an alternative source of rhFVIIa at potentially lower cost with easily expandable manufacturing capacity that could contribute to cover the future patient needs.

What can be learned in the snake antivenom field from the developments in human plasma derived products?

Human plasma-derived medicinal products and snake antivenom immunoglobulins are unique and complex therapeutic protein products. Human plasma products are obtained by fractionating large pools of plasma collected from blood plasma donors. They comprise a wide range of protein products, including polyvalent and hyperimmune immunoglobulins, coagulation factors, albumin, and various protease inhibitors that are transfused to patients affected by congenital or acquired protein deficiencies, immunological disorders, or metabolic diseases. Snake antivenoms are manufactured from pools of plasma collected from animals, typically horses, which have been immunized against snake venoms. Transfusing antivenoms is the cornerstone therapy to treat patients affected by snakebite envenoming. Over the last thirty years, much technical and regulatory evolution has been implemented to ensure that this class of biologicals meets modern quality requirements. The purpose of this review is to compare the main developments that took place in plasma production, protein fractionation, pathogen safety, quality control, preclinical and clinical studies, and regulations of these products. We also analyze whether both fields have been influencing and cross-fertilizing each other technically and in regulatory aspects to reach modern safety and efficacy standards at global levels, and how experience in the human plasma fractionation industry can further impact the manufacture of snake antivenom and that of other animal-derived antisera.

Broad substrate affinity and catalytic diversity of fibrinolytic enzyme from Pheretima posthumous-Purification and molecular characterization study

In this research, a serine protease was isolated and purified from Indian earthworm Pheretima posthumous by fractionation with ammonium sulfate followed by ion exchange and size exclusion chromatography. The molecular weight of purified protease was determined 29.5kDa by Maldi-TOF/MS. The enzyme exhibited a maximum proteolytic activity of 1.2U/ml with specific activity of 17.65U/mg at pH 8 and temperature 40°C. 2D electrophoresis study illustrated purity of enzyme, purified as a single peptide and isoelectric point (pI) 4.5. The enzyme has shown tremendous stability and proteolytic activity in the wide range of pH range (4-12) and temperatures (20-60°C). The kinetic constant Km and Vmax of purified protease were reported 0.09mg/ml and 23.25mg/ml/min. The enzyme also possesses excellent catalytic capacity with Kcat (341.9min^-1) and catalytic efficiency (3798.88). The N-terminal sequence of purified protease Arg-Lys-Lys-Gly-Ala-Ser-Try-Phe-Try-Pro-Trp-Ser-Val-Lys-Lys-Arg, PMF and MS/MS studies had shown a partial homology with Lumbrokinase-P2 (2) from Lumbricus rubellus. The CD spectroscopy result provided an evidence for broad substrate affinity and stability of enzyme. The different forms of secondary structures determined in EFE result broad substrate affinity of enzyme.

Plant Based Bioreactors of Recombinant Cytokines (Review)

Cytokines are a family of signaling polypeptides involved in intercellular interactions in the process of the immune response, as well as in the regulation of a number of normal physiological functions. Cytokines are used in medicine for the treatment of cancer, immune disorders, viral infections, and other socially significant diseases, but the extent of their use is limited by the high production cost of the active agent. The development of this area of pharmacology is associated with the success of genetic engineering, which allows the production of significant amounts of protein by transgenic organisms. The review discusses the latest advances in the production of various cytokines with the use of genetically modified plants.

Production of Human Albumin in Pigs Through CRISPR/Cas9-Mediated Knockin of Human cDNA into Swine Albumin Locus in the Zygotes

Precise genome modification in large domesticated animals is desirable under many circumstances. In the past it is only possible through lengthy and burdensome cloning procedures. Here we attempted to achieve that goal through the use of the newest genome-modifying tool CRISPR/Cas9. We set out to knockin human albumin cDNA into pig Alb locus for the production of recombinant human serum albumin (rHSA). HSA is a widely used human blood product and is in high demand. We show that homologous recombination can occur highly efficiently in swine zygotes. All 16 piglets born from the manipulated zygotes carry the expected knockin allele and we demonstrated the presence of human albumin in the blood of these piglets. Furthermore, the knockin allele was successfully transmitted through germline. This success in precision genomic engineering is expected to spur exploration of pigs and other large domesticated animals to be used as bioreactors for the production of biomedical products or creation of livestock strains with more desirable traits.

“Go no Go” in plasma fractionation in the world’s emerging economies: still a question asked 70 years after the COHN process was developed!

In the late 1980s, following the human immunodeficiency virus (HIV) epidemic and transfusion-transmitted infections from plasma-derived coagulation factor concentrates to hemophiliacs, many “advanced thinkers” claimed that plasma-derived products would be completely replaced by the year 2000 by safe recombinant products in most developed countries. However, things have not turned out that way, due to both the continual progress witnessed in plasma fractionation and viral-reduction technologies and technical difficulties still being encountered in developing more cost-effective non-immunogenic, fully active recombinant therapeutic proteins.

Accordingly, plasma fractionation remains a reasonably healthy industry worldwide, with an ever-increasing volume of plasma fractionated each year to meet the demands for safe and effective plasma-derived medicines at the global level. While high-income countries currently have generally good access to a panel of plasma-derived and recombinant products, desperate shortages of fractionated plasma products remain in developing economies, and patients still have to be treated inadequately.

The steady development of the collection of whole blood in developing economies, to gradually cover the recognized needs for red blood cell concentrates, generates an increasing volume of recovered plasma that is currently wasted. Incentives are therefore high for those countries to consider fractionating such plasma as a means of enhancing their supply of products to treat patients, thereby also decreasing the level of dependence on imported products.

Challenges of local plasma fractionation in developing economies are high, in a context where the technological and regulatory sophistication of the plasma fractionation industry is often underestimated, and the blood supply may be exposed to emerging infectious agents. In parallel, plasma product quality requirements and drivers are evolving in developed economies as is the awareness of clinicians to newer uses of products such as intravenous immunoglobulins, somewhat deviating from what currently remain the basic needs of developing countries in terms of affordable safe plasma products.

Global market trends for plasma-derived products, through plasma fractionation, are still increasing, despite increasing use of recombinant products, and attention is being focused on the five Ws of the fractionation field: which products; where; when; what and how much; and who will be the main suppliers?

Plasma and Plasma Protein Product Transfusion: A Canadian Blood Services Centre for Innovation Symposium

Plasma obtained via whole blood donation processing or via apheresis technology can either be transfused directly to patients or pooled and fractionated into plasma protein products that are concentrates of 1 or more purified plasma protein. The evidence base supporting clinical efficacy in most of the indications for which plasma is transfused is weak, whereas high-quality evidence supports the efficacy of plasma protein products in at least some of the clinical settings in which they are used. Transfusable plasma utilization remains composed in part of applications that fall outside of clinical practice guidelines. Plasma contains all of the soluble coagulation factors and is frequently transfused in efforts to restore or reinforce patient hemostasis. The biochemical complexities of coagulation have in recent years been rationalized in newer cell-based models that supplement the cascade hypothesis. Efforts to normalize widely used clinical hemostasis screening test values by plasma transfusion are thought to be misplaced, but superior rapid tests have been slow to emerge. The advent of non-vitamin K-dependent oral anticoagulants has brought new challenges to clinical laboratories in plasma testing and to clinicians needing to reverse non-vitamin K-dependent oral anticoagulants urgently. Current plasma-related controversies include prophylactic plasma transfusion before invasive procedures, plasma vs prothrombin complex concentrates for urgent warfarin reversal, and the utility of increased ratios of plasma to red blood cell units transfused in massive transfusion protocols. The first recombinant plasma protein products to reach the clinic were recombinant hemophilia treatment products, and these donor-free equivalents to factors VIII and IX are now being supplemented with novel products whose circulatory half-lives have been increased by chemical modification or genetic fusion. Achieving optimal plasma utilization is an ongoing challenge in the interconnected worlds of transfusable plasma, plasma protein products, and recombinant and engineered replacements.

Human plasma-derived immunoglobulin G fractionated by an aqueous two-phase system, caprylic acid precipitation, and membrane chromatography has a high purity level and is free of detectable in vitro thrombogenic activity

BACKGROUND AND OBJECTIVES

Instituto Clodomiro Picado has developed an immunoglobulin G (IgG) plasma fractionation process combining a polyethylene glycol/phosphate aqueous two-phase system (ATPS), caprylic acid precipitation and anion-exchange membrane chromatography. We evaluated the purity and in vitro thrombogenicity of such IgG, in line with current international requirements.

MATERIALS AND METHODS

Contributions of the different production steps to reduce thrombogenicity were assessed at 0·2 l-scale, and then the methodology was scaled-up to a 10 l-scale and final products (n = 3) were analysed. Purity, immunoglobulin composition, and subclass distribution were determined by electrophoretic and immunochemical methods. The in vitro thrombogenic potential was determined by a thrombin generation assay (TGA) using a Technothrombin fluorogenic substrate. Prekallikrein activator (PKA), plasmin, factor Xa, thrombin and thrombin-like activities were assessed using S-2302, S-2251, S-2222, S-2238 and S-2288 chromogenic substrates, respectively, and FXI by an ELISA.

RESULTS

The thrombogenicity markers were reduced mostly during the ATPS step and were found to segregate mostly into the discarded liquid upper phase. The caprylic acid precipitation eliminated the residual procoagulant activity. The IgG preparations made from the 10 l-batches contained 100% gamma proteins, low residual IgA and undetectable IgM. The IgG subclass distribution was not substantially affected by the process. TGA and amidolytic activities revealed an undetectable in vitro thrombogenic risk and the absence of proteolytic enzymes in the final product.

CONCLUSIONS

Fractionating human plasma by an ATPS combined with caprylic acid and membrane chromatography resulted in an IgG preparation of high purity and free of a detectable in vitro thrombogenic risk.

Preparation, quality criteria, and properties of human blood platelet lysate supplements for ex vivo stem cell expansion

Most clinical applications of human multipotent mesenchymal stromal cells (MSCs) for cell therapy, tissue engineering, regenerative medicine, and treatment of immune and inflammatory diseases require a phase of isolation and ex vivo expansion allowing a clinically meaningful cell number to be reached. Conditions used for cell isolation and expansion should meet strict quality and safety requirements. This is particularly true for the growth medium used for MSC isolation and expansion. Basal growth media used for MSC expansion are supplemented with multiple nutrients and growth factors. Fetal bovine serum (FBS) has long been the gold standard medium supplement for laboratory-scale MSC culture. However, FBS has a poorly characterized composition and poses risk factors, as it may be a source of xenogenic antigens and zoonotic infections. FBS has therefore become undesirable as a growth medium supplement for isolating and expanding MSCs for human therapy protocols. In recent years, human blood materials, and most particularly lysates and releasates of platelet concentrates have emerged as efficient medium supplements for isolating and expanding MSCs from various origins. This review analyzes the advantages and limits of using human platelet materials as medium supplements for MSC isolation and expansion. We present the modes of production of allogeneic and autologous platelet concentrates, measures taken to ensure optimal pathogen safety profiles, and methods of preparing PLs for MSC expansion. We also discuss the supply of such blood preparations. Produced under optimal conditions of standardization and safety, human platelet materials can become the future 'gold standard' supplement for ex vivo production of MSCs for translational medicine and cell therapy applications.

[Historical changes in the list of plasma fractionation products placed on the WHO Model List of Essential Medicines]

The purpose of this study was to summarize the historical changes in the list of plasma fractionation products (PFP) placed on the Model List of Essential Medicines (EML) issued by the World Health Organization (WHO). PFP such as albumin, blood coagulation factors, and immunoglobulins are derived from blood collected from thousands of people. PFP have been listed since the first edition of the EML (1977). However, the PFP listed on the EML have changed dramatically because EML's selection process has changed from experience-based to evidence-based. For example, albumin, which had been listed since the 2nd edition (1979), was deleted in the 11th edition (2000) because of the uncertainty of its efficacy. Human immunoglobulin normal, which had been deleted from the 13th edition (2003), was relisted in the 15th edition (2007). Moreover, the WHO has issued several resolutions and guidelines regarding PFP production, quality, and safety in order to promote the establishment of blood programmes in every nation. The focus of WHO's EML selection process has changed over 30 years. In the 20th century, WHO mainly focused on PFP efficacy, quality, and safety problems. However, currently the focus is on the problem of PFP accessibility, especially in developing countries. Therefore, it would be important to know how to capitalize on established knowledge and production technology to increase the accessibility of PFP worldwide.

Factor VIII assay mimicking in vivo coagulation conditions

Under certain circumstances, the determination of coagulation factor VIII (FVIII) is hampered by assay discrepancies between clotting and chromogenic approaches. These are observed in certain patients' plasma as well as in certain concentrates. We intended to develop a novel assay for the quantification of coagulation FVIII which reflects the physiological situation better than the established assays. It is based on plasma without chelation of divalent cations and simultaneously minimizes the generation of activated factors which could function as uncontrolled triggers of coagulation. FVIII deficient plasma is prepared with the aid of biotinylated antibodies against FVIII from normal plasma in presence of inhibitors of contact activation. To start the assay only tiny amounts of activated FIX serve as trigger. The FVIII determination is performed in a kinetic experiment and is based on the cleavage of a fluorogenic substrate for activated FX. FVIII concentrations between 0.01 and 1 IU mL(-1) are easily determined. Plasma-derived and recombinant FVIII concentrates were compared. All plasma-derived concentrates were found to contain FVIII activities within the specification of the manufacturer. Recombinant concentrates yielded only 35-50% of the claimed potency. The novel in vivo-like assay avoids the undue advantage or disadvantage of certain product characteristics by eliminating unphysiological assay conditions. Its usefulness could turn out in future experiments with plasma from haemophilia A patients.

Single-donor allogeneic platelet fibrin glue and osteoconductive scaffold in orbital floor fracture reconstruction

BACKGROUND

Commonly used materials for orbital floor fracture reconstruction include autologous cranial bone graft and titanium mesh. We have evaluated here a biomaterial combining biphasic calcium phosphate (hydroxyapatite [HA]/β-tricalcium phosphate [TCP]) osteoconductive scaffold with single-donor allogeneic platelet fibrin glue.

METHODS

The study was conducted on 10 consecutive patients with a follow-up of up to 4 years. Platelet fibrin glue was prepared by mixing equal volumes of single-donor platelet-rich plasma and cryoprecipitate with HA/β-TCP followed by activation with human thrombin prepared by plasma activation. Postoperative evaluations included serial photographs, repeated physical examination, and 3-dimensional computed tomography scan performed 2 years after surgery.

RESULTS

The fibrin-rich platelet biomaterial was easy to mold and to apply on the surgical site allowing the surgeon to sculpt accurately the bone defect, providing mechanical stability while avoiding spillage of the scaffold. No infection of the orbit or extrusion of HA/β-TCP was observed. Ocular motility was normal, and no diplopia or enophthalmos of the injured orbit was noted. Coronal computed tomography scans of the reconstructed orbits revealed good restoration of the orbital floor defect in all 10 patients.

CONCLUSIONS

The use of single-donor platelet fibrin glue combined with an osteoconductive scaffold offers a valuable alternative to autologous cranial bone graft or titanium mesh in the reconstruction of orbital floor bone defect.

Experimental and in silico modelling analyses of the gene expression pathway for recombinant antibody and by-product production in NS0 cell lines

Monoclonal antibodies are commercially important, high value biotherapeutic drugs used in the treatment of a variety of diseases. These complex molecules consist of two heavy chain and two light chain polypeptides covalently linked by disulphide bonds. They are usually expressed as recombinant proteins from cultured mammalian cells, which are capable of correctly modifying, folding and assembling the polypeptide chains into the native quaternary structure. Such recombinant cell lines often vary in the amounts of product produced and in the heterogeneity of the secreted products. The biological mechanisms of this variation are not fully defined. Here we have utilised experimental and modelling strategies to characterise and define the biology underpinning product heterogeneity in cell lines exhibiting varying antibody expression levels, and then experimentally validated these models. In undertaking these studies we applied and validated biochemical (rate-constant based) and engineering (nonlinear) models of antibody expression to experimental data from four NS0 cell lines with different IgG4 secretion rates. The models predict that export of the full antibody and its fragments are intrinsically linked, and cannot therefore be manipulated individually at the level of the secretory machinery. Instead, the models highlight strategies for the manipulation at the precursor species level to increase recombinant protein yields in both high and low producing cell lines. The models also highlight cell line specific limitations in the antibody expression pathway.

The first recombinant human coagulation factor VIII of human origin: human cell line and manufacturing characteristics

INTRODUCTION

Since the early 1990s, recombinant human clotting factor VIII (rhFVIII) produced in hamster cells has been available for haemophilia A treatment. However, the post-translational modifications of these proteins are not identical to those of native human FVIII, which may lead to immunogenic reactions and the development of inhibitors against rhFVIII. For the first time, rhFVIII produced in a human host cell line is available.

AIM

We describe here the establishment of the first human production cell line for rhFVIII and the manufacturing process of this novel product.

METHODS AND RESULTS

A human cell line expressing rhFVIII was derived from human embryonic kidney (HEK) 293 F cells transfected with an FVIII expression plasmid. No virus or virus-like particles could be detected following extensive testing. The stringently controlled production process is completely free from added materials of animal or human origin. Multistep purification employing a combination of filtration and chromatography steps ensures the efficient removal of impurities. Solvent/detergent treatment and a 20 nm pore size nanofiltration step, used for the first time in rhFVIII manufacturing, efficiently eliminate any hypothetically present viruses. In contrast to hamster cell-derived products, this rhFVIII product does not contain hamster-like epitopes, which might be expected to be immunogenic.

CONCLUSIONS

HEK 293 F cells, whose parental cell line HEK 293 has been used by researchers for decades, are a suitable production cell line for rhFVIII and will help avoid immunogenic epitopes. A modern manufacturing process has been developed to ensure the highest level of purity and pathogen safety.

Human platelet concentrates: a source of solvent/detergent-treated highly enriched brain-derived neurotrophic factor

BACKGROUND

Human blood platelets (PLTs) contain brain-derived neurotrophic factor (BDNF), a neurotrophin that binds to neurotrophic tropomyosin-related kinase B (TrkB) receptor on central nervous system cells. This binding promotes neural synaptic plasticity and memory and prevents neuronal degeneration. Alterations in BDNF homeostasis are associated with aging and are found in several neurodegenerative conditions such as Alzheimer's, Huntington's, and Parkinson's diseases and multiple sclerosis. We have developed PLT viral inactivation and chromatographic fractionation processes and decided here to identify fractions enriched in BDNF.

STUDY DESIGN AND METHODS

PLT concentrates (PCs) were treated by solvent/detergent (S/D), extracted by oil, and subjected to fractionation (C18, sulfopropyl [SP]-Sepharose, diethylaminoethyl [DEAE]-Sepharose, or activated charcoal). BDNF and pro-BDNF were evaluated by enzyme-linked immunosorbent assay, and Western blot. TrkB was studied by Western blot. Tri-n-butyl phosphate (TnBP) was quantified by high-performance liquid chromatography, and Triton X-45 by gas chromatography.

RESULTS

The mean BDNF content of 2.9 ± 0.7 ng/mL in PC was noted to increase to 56.2 ± 2.4 ng/mL after S/D treatment and remained stable during oil extraction. Approximately 70% of the BDNF content was recovered after C18 chromatography. BDNF did not bind to DEAE-Sepharose and was almost completely adsorbed by charcoal. Chromatography on SP-Sepharose yielded a highly enriched 13-kDa mature BDNF fraction that was more than 170-fold purified, with a mean of 137 ± 29.4 ng/mL and 82% chromatographic recovery, devoid of detectable TnBP and Triton X-45. Pro-BDNF and TrkB proteins were not detected in the PLT extracts.

CONCLUSION

We obtained a S/D-treated, highly enriched mature PLT-derived BDNF fraction that could help unveil the pharmacokinetics, pharmacodynamic, and potential therapeutic applications of the BDNF neurotrophin.

Fucose content of monoclonal antibodies can be controlled by culture medium osmolality for high antibody-dependent cellular cytotoxicity

Antibody-dependent cellular cytotoxicity (ADCC) is dependent on the fucose content of oligosaccharides bound to monoclonal antibodies (MAbs). As MAbs with a low fucose content exhibit high ADCC activity, it is important to control the defucosylation levels (deFuc%) of MAbs and to analyze the factors that affect deFuc%. In this study, we observed that the deFuc% was inversely related to culture medium osmolality for MAbs produced in the rat hybridoma cell line YB2/0, with r (2) values as high as 0.92. Moreover, deFuc% exhibited the same correlation irrespective of the type of compound used for regulating osmolality (NaCl, KCl, fucose, fructose, creatine, or mannitol) at a culture scale ranging from 1 to 400 L. We succeeded in controlling MAb deFuc% by maintaining a constant medium osmolality in both perfusion and fed-batch cultures. In agreement with these observations, reverse transcription PCR analyses revealed decreased transcription of genes involved in glycolysis, GDP-fucose supply, and fucose transfer under hypoosmotic conditions.