Non-inferiority of liquid thyroxine in comparison to tablets formulation in the treatment of children with congenital hypothyroidism.

OBJECTIVES: The aim of the current prospective randomized control study was to assess efficacy, safety, and non-inferiority of a new liquid L-thyroxine formulation dissolved in glycerol and water (T4® drops, produced by a Greek pharmaceutical Company, Uni-Pharma, Athens, Greece) in comparison to the standard Tablets form (T4® tablets, Uni-Pharma, Athens, Greece) in the substitutive treatment of children with congenital hypothyroidism (CH). METHODS: Thirty-nine children with CH, aged 3-12 years old, were enrolled in the study, after parental Informed Consent has been obtained, while three patients were lost from follow-up. At baseline, all participants had normal thyroid-stimulating hormone (TSH) and Free T4 values. Patients were randomly subdivided according to the assigned treatment in Group A (n=17)-Tablet Form and Group B (n=19)-Liquid Form. TSH and Free T4 levels were evaluated at 0, 2, 4, and 6 months. RESULTS: TSH values showed a statistically significant difference (p=0.017) between groups only at six months (Group A having higher TSH levels than Group B, albeit within the normal range), while Free T4 levels had no statistical difference throughout the six month study period and were always within the normal range. Moreover, dose adjustments were more frequent in Group A (p=0.038) during the six months. Liquid L-thyroxine substitutive treatment exhibited no statistically significant adverse effects in comparison to the widely used tablets. CONCLUSIONS: Levothyroxine (LT4) as liquid solution formulation is safe and noninferior to the widely used L-thyroxine Tablets, with less need for dose adjustment, and can therefore be safely used in the treatment of children with CH.

[Neonatal screening in Europe revisited: An ISNS-perspective on the current state and developments since 2010]. / Dépistage néonatal en Europe - Évolution au cours de la dernière décennie et analyse de la situation actuelle par la Société internationale de dépistage néonatal.

Neonatal screening (NBS) was initiated in Europe during the 1960s with the screening for phenylketonuria. The panel of screened disorders ("conditions") then gradually expanded, with a boost in the late 1990's with the introduction of tandem mass spectrometry (MS/MS), making it possible to screen for 40-50 conditions in one blood spot. The most recent additions to screening programmes (screening for cystic fibrosis, severe combined immunodeficiency and spinal muscular atrophy) were assisted by or realised through the introduction of molecular genetics techniques. For this survey we collected data from 51 European countries. We report on the developments between 2010 and 2020, and highlight the achievements made during this period. We also identify areas where further progress can be made, mainly by exchanging knowledge and learning from experiences in neighbouring countries. Between 2010 and 2020, most NBS programmes in geographical Europe have matured considerably, both in terms of methodology (modernised) and with regards to the panel of conditions screened (expanded). These developments indicate that more collaboration in Europe through European organisations is gaining momentum. Only by working together can we accomplish the timely detection of newborn infants potentially suffering from one of the many rare diseases and take appropriate actions.

TITLE: Dépistage néonatal en Europe - Évolution au cours de la dernière décennie et analyse de la situation actuelle par la Société internationale de dépistage néonatal. ABSTRACT: Le dépistage néonatal a débuté en Europe dans les années 1960 avec celui de la phénylcétonurie. Le nombre de maladies dépistées a, par la suite, augmenté progressivement, de manière plus marquée à la fin des années 1990 avec l'arrivée de la spectrométrie de masse en tandem (MS/MS) qui a permis le dépistage de 40 à 50 maladies sur une seule goutte de sang séché. Les ajouts les plus récents à cette liste de maladies (mucoviscidose, déficits immunitaires combinés sévères et atrophie musculaire spinale) ont été rendus possibles grâce à la génétique moléculaire. À partir des informations provenant de 51 pays d'Europe, nous décrivons dans cette revue l'évolution du dépistage entre 2010 et 2020, ainsi que les progrès réalisés pendant cette période, tout en soulignant les aspects qui méritent d'être améliorés. Des progrès pourront en effet être accomplis grâce aux échanges d'informations et, pour certains pays, en tirant profit de l'expérience acquise dans des pays voisins. La plupart des programmes de dépistage mis en place dans l'Europe « géographique ¼ au cours de cette période ont gagné en maturité en termes méthodologiques (modernisation des techniques) et en termes quantitatifs (augmentation du nombre des maladies dépistées). Ces développements nous montrent que la collaboration entre les différentes organisations s'accélère en Europe. Ce n'est qu'en travaillant ensemble que nous pourrons identifier en temps opportun les nouveau-nés atteints d'une des nombreuses maladies rares détectables et prendre les mesures qui s'imposent.

Neonatal Screening in Europe Revisited: An ISNS Perspective on the Current State and Developments Since 2010.

Neonatal screening (NBS) was initiated in Europe during the 1960s with the screening for phenylketonuria. The panel of screened disorders ("conditions") then gradually expanded, with a boost in the late 1990s with the introduction of tandem mass spectrometry (MS/MS), making it possible to screen for 40-50 conditions using a single blood spot. The most recent additions to screening programmes (screening for cystic fibrosis, severe combined immunodeficiency and spinal muscular atrophy) were assisted by or realised through the introduction of molecular technologies. For this survey, we collected data from 51 European countries. We report the developments between 2010 and 2020 and highlight the achievements reached with the progress made in this period. We also identify areas where further progress can be made, mainly by exchanging knowledge and learning from experiences in neighbouring countries. Between 2010 and 2020, most NBS programmes in geographical Europe matured considerably, both in terms of methodology (modernised) and with regard to the panel of conditions screened (expanded). These developments indicate that more collaboration in Europe through European organisations is gaining momentum. We can only accomplish the timely detection of newborn infants potentially suffering from one of the many rare diseases and take appropriate action by working together.

Adrenal Steroids in Female Hypothyroid Neonates: Unraveling an Association Between Thyroid Hormones and Adrenal Remodeling.

CONTEXT: The adrenal gland undergoes substantial remodeling during the neonatal period, an essential developmental process that remains incompletely understood. With respect to control over the remodeling process and, specifically, the role of thyroid hormones (THs), no human studies have been published. The effects of both hypo- and hyperthyroidism have only been evaluated in adults, focusing on the mature adrenal. Recent studies have identified expression of the TH receptor ß1 in the mouse adrenal X-zone and have demonstrated that TH administration could alter the postnatal adrenal remodeling process. OBJECTIVE: To address whether THs influence adrenal steroid profiles and adrenal remodeling during the neonatal period. METHODS: We compared the adrenal steroid profile of a naturally occurring prototype, female neonates with severe congenital hypothyroidism (CH) (n = 22, upon diagnosis of CH), with that of euthyroid neonates (n = 20). RESULTS: Significantly higher levels of adrenal steroids (17-OH-progesterone, dehydroepiandrosterone sulfate, Δ4-androstenedione, and testosterone) were measured in neonates with severe CH compared with euthyroid neonates and returned to within normal range after euthyroid state had been established on l-thyroxine replacement therapy, whereas cortisol levels did not differ. TSH values in the CH group were positively correlated with circulating adrenal steroids, whereas free T4 levels were negatively correlated with circulating adrenal steroids. CONCLUSIONS: The hormonal profile of female neonates with severe CH suggests a more active adrenal fetal zone compared with control subjects. These data indirectly associate THs with the adrenal remodeling and maturation process in humans. Based on our results, we suggest that severe hypothyroidism decelerates the involution of the adrenal fetal zone that normally occurs postnatally.

How Long Does (S)He Have? Retrospective Analysis of Outcomes After Palliative Extubation in Elderly, Chronically Critically Ill Patients.

OBJECTIVE: For chronically critically ill elderly patients on mechanical ventilation, prognosis for significant recovery may be minimal. These individuals, or their surrogates, may decide for "palliative extubation." A common prognostic question arises: "How long does she/he have?" This study describes demographics, mortality, time to death, and factors associated with death after palliative extubation. DESIGN, SETTING, AND PATIENTS: Retrospective 3-year study in community hospital with ethnically diverse elderly population. Chronically critically ill patients followed from palliative extubation to death or survival to discharge. MEASURES: Mortality/survival following palliative extubation, time to death or discharge, factors associated with death. RESULTS: Hundred and forty-eight subjects underwent palliative extubation. Mean age: 78 years, 60% female, ethnically diverse with 46% white, and 54% others. Top diagnostic categories: sepsis (47%) and respiratory failure (22%). After extubation, 114 patients (77%) died in hospital and 34 (23%) were discharged. Of those who died, median time to death 8.9 hours (range, 4 min to 7 d). Mortality proportion was 56% at 24 hours and increased with time. Factors associated with early death: Systolic blood pressure less than 90 (p = 0.002) and Charlson Comorbidity Index that is above 6 or 0 (p = 0.002). CONCLUSIONS: Palliative extubation at end of life was an option selected by an ethnically diverse elderly population. Approximately three-fourths of subjects died in hospital, and one-fourth was discharged alive. Over 50% who died did so within 24 hours, making this useful information for counseling and anticipatory planning. Subjects with systolic blood pressure less than 90 and Charlson Comorbidity Index that is very low or very high had higher mortality.

Asymptomatic rectal colonization with carbapenem-resistant Enterobacteriaceae and Clostridium difficile among residents of a long-term care facility in New York City.

BACKGROUND: Residents of long-term care facilities (LTCFs) are at increased risk for colonization and development of infections with multidrug-resistant organisms. This study was undertaken to determine prevalence of asymptomatic rectal colonization with Clostridium difficile (and proportion of 027/NAP1/BI ribotype) or carbapenem-resistant Enterobacteriaceae (CRE) in an LTCF population. METHODS: Active surveillance was performed for C difficile and CRE rectal colonization of 301 residents in a 320-bed (80-bed ventilator unit), hospital-affiliated LTCF with retrospective chart review for patient demographics and potential risk factors. RESULTS: Over 40% of patients had airway ventilation and received enteral feeding. One-third of these patients had prior C difficile-associated infection (CDI). Asymptomatic rectal colonization with C difficile occurred in 58 patients (19.3%, one-half with NAP1+), CRE occurred in 57 patients (18.9%), and both occurred in 17 patients (5.7%). Recent CDI was significantly associated with increased risk of C difficile ± CRE colonization. Multivariate logistic regression analysis revealed presence of tracheostomy collar to be significant for C difficile colonization, mechanical ventilation to be significant for CRE colonization, and prior CDI to be significant for both C difficile and CRE colonization. CONCLUSIONS: The strong association of C difficile or CRE colonization with disruption of normal flora by mechanical ventilation, enteral feeds, and prior CDI carries important implications for infection control intervention in this population.

Design, synthesis and application of benzyl-sulfonate biomimetic affinity adsorbents for monoclonal antibody purification from transgenic corn.

The human anti-human immunodeficiency virus (HIV) antibody 2G12 (mAb 2G12) is one of the most broadly neutralizing antibodies against HIV that recognizes a unique epitope on the surface glycoprotein gp120. In the present work, a limited affinity-ligand library was synthesized and evaluated for its ability to bind and purify recombinant mAb 2G12 expressed in transgenic corn. The affinity ligands were structural fragments of polysulfonate triazine dye Cibacron Blue 3GA (CB3GA) and represent novel lead scaffolds for designing synthetic affinity ligands. Solid phase chemistry was used to synthesize variants of CB3GA lead ligand. One immobilized ligand, bearing 4-aminobenzyl sulfonic acid (4ABS) linked on two chlorine atoms of the triazine ring (4ABS-Trz-4ABS), displayed high affinity for mAb 2G12. Absorption equilibrium, 3D molecular modelling and molecular dynamics simulation studies were carried out to provide a detailed picture of the 4ABS-Trz-4ABS interaction with mAb 2G12. This biomimetic affinity ligand was exploited for the development of a facile two-step purification protocol for mAb 2G12. In the first step of the procedure, mAb 2G12 was purified on an S-Sepharose FF cation exchanger, and in the second step, mAb 2G12 was purified using affinity chromatography on 4ABS-Trz-4ABS affinity adsorbent. Analysis of the antibody preparation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and enzyme-linked immunosorbent assay showed that the mAb 2G12 was fully active and of sufficient purity suitable for analytical applications.

Application of a PEG/salt aqueous two-phase partition system for the recovery of monoclonal antibodies from unclarified transgenic tobacco extract.

Aqueous two-phase partition systems (ATPS) have been widely used for the separation of a large variety of biomolecules. In the present report, the application of a polyethylene glycol/phosphate (PEG/phosphate) ATPS for the separation of anti-HIV monoclonal antibodies 2G12 (mAb 2G12) and 4E10 (mAb 4E10) from unclarified transgenic tobacco crude extract was investigated. Optimal conditions that favor opposite phase partitioning of plant debris/mAb as well as high recovery and purification were found to be 13.1% w/w (PEG 1500), 12.5% w/w (phosphate) at pH 5 with a phase ratio of 1.3 and 8.25% w/w unclarified tobacco extract load. Under these conditions, mAb 2G12 and mAb 4E10 were partitioned at the bottom phosphate phase with 85 and 84% yield and 2.4- and 2.1-fold purification, respectively. The proposed ATPS was successfully integrated in an affinity-based purification protocol, using Protein A, yielding antibodies of high purity and yield. In this study, ATPS was shown to be suitable for initial protein recovery and partial purification of mAb from unclarified transgenic tobacco crude extract.

Combinatorial de novo design and application of a biomimetic affinity ligand for the purification of human anti-HIV mAb 4E10 from transgenic tobacco.

Monoclonal anti-HIV antibody 4E10 (mAb 4E10) is one of the most broadly neutralizing antibodies against HIV, directed against a specific epitope on envelope protein gp41. In the present study, a combinatorial de novo design approach was used for the development of a biomimetic ligand for the affinity purification of mAb 4E10 from tobacco transgenic extract in a single chromatographic step. The biomimetic ligand (4E10lig) was based on a L-Phe/beta-Ala bi-substituted 1,3,5-triazine (Trz) scaffold (beta-Ala-Trz-L-Phe, 4E10lig) which potentially mimics the more pronounced electrostatic and hydrophobic interactions of mAb 4E10-binding sequence determined by screening of a random peptide library. This library was comprised of Escherichia coli cells harboring a plasmid (pFlitrx) engineered to express a fusion protein containing random dodecapeptides that were inserted into the active loop of thioredoxin, which itself was inserted into the dispensable region of the flagellin gene. Adsorption equilibrium studies with this biomimetic ligand and mAb 4E10 determined a dissociation constant (K(D)) of 0.41 +/- 0.05 microM. Molecular modeling studies of the biomimetic ligand revealed that it can potentially occupy the same binding site as the natural binding core peptide epitope. The biomimetic affinity adsorbent was exploited in the development of a facile mAb 4E10 purification protocol, affording mAb 4E10 of high purity (approximately 95%) with good overall yield (60-80%). Analysis of the antibody preparation by SDS-PAGE, enzyme-linked immunosorbent assays (ELISA), and western blot showed that the mAb 4E10 was fully active and free of degraded variants, polyphenols, and alkaloids.

Engineering sensitive glutathione transferase for the detection of xenobiotics.

Cytosolic glutathione transferases (GSTs) are a major reserve of high-capacity ligand binding proteins which recognise a large variety of hydrophobic compounds. In the present study, the binding of non-substrate xenobiotic compounds (herbicides and insecticides) to maize GST I was investigated by employing kinetic inhibition studies, site-directed mutagenesis and molecular modelling studies. The results showed that the xenobiotics bind at the substrate binding site. Based on in silico docking analysis, two residues were selected for assessing their contribution to xenobiotic binding. The mutant Gln53Ala of GST I Exhibits 9.2-fold higher inhibition potency for the insecticide malathion, compared to the wild-type enzyme. A potentiometric assay was developed for the determination of malathion using the Gln53Ala mutant enzyme. The assay explores the ability of the xenobiotic to promote inhibition of the GST-catalysing 1-chloro-2,4-dinitrobenzene (CDNB)/glutathione (GSH) conjugation reaction. The sensing scheme is based on the pH change occurring in a low buffer system by the GST reaction, which is measured potentiometrically using a pH electrode. Calibration curve was obtained for malathion, with useful concentration range 0-20 microM. The method's reproducibility was in the order of +/-3-5% and malathion recoveries were 96.7+/-2.8%. Immobilized Gln53Ala mutant GST was used to assemble a biosensor for malathion. The enzyme was immobilized by crosslinking with glutaraldehyde and trapped behind a semipermeable membrane in front of the pH electrode. The results demonstrated that the immobilized enzyme behaved similar to free enzyme.

Chemical and genetic engineering strategies to improve the potency of pharmaceutical proteins and enzymes.

Over the last decade there has been significant progress in understanding the molecular basis of disease processes. At the same time the technological advances in the area of genomics and the efforts in proteomics research have increased the possibility of discovering many proteins with defined therapeutic functions. A large number of these proteins have found clinical application. Despite the importance of proteins as therapeutic agents, they have a number of disadvantages in comparison to small-molecule drugs, including immunogenicity and antigenicity, poor efficacy and oral bioavailability as well as, in many cases, short serum half-lives. To date, the most promising approaches for improving protein therapeutics rely on the use of genetic engineering and site-specific chemical synthesis/modification techniques. Improving the potency of protein drugs by employing modern recombinant DNA technologies and novel chemical synthesis techniques is of primary importance, not only because of the enormous medicinal benefit but also because of the significant economic edge an improved drug can provide in today's competitive market.

Structure-guided alteration of coenzyme specificity of formate dehydrogenase by saturation mutagenesis to enable efficient utilization of NADP+.

Formate dehydrogenase from Candida boidinii (CboFDH) catalyses the oxidation of formate anion to carbon dioxide with concomitant reduction of NAD(+) to NADH. CboFDH is highly specific to NAD(+) and virtually fails to catalyze the reaction with NADP(+). Based on structural information for CboFDH, the loop region between beta-sheet 7 and alpha-helix 10 in the dinucleotide-binding fold was predicted as a principal determinant of coenzyme specificity. Sequence alignment with other formate dehydrogenases revealed two residues (Asp195 and Tyr196) that could account for the observed coenzyme specificity. Positions 195 and 196 were subjected to two rounds of site-saturation mutagenesis and screening and enabled the identification of a double mutant Asp195Gln/Tyr196His, which showed a more than 2 x 10(7)-fold improvement in overall catalytic efficiency with NADP(+) and a more than 900-fold decrease in the efficiency with NAD(+) as cofactors. The results demonstrate that the combined polar interactions and steric factors comprise the main structural determinants responsible for coenzyme specificity. The double mutant Asp195Gln/Tyr196His was tested for practical applicability in a cofactor recycling system composed of cytochrome P450 monooxygenase from Bacillus subtilis, (CYP102A2), NADP(+), formic acid and omega-(p-nitrophenyl)dodecanoic acid (12-pNCA). Using a 1250-fold excess of 12-pNCA over NADP(+) the first order rate constant was determined to be equal to k(obs) = 0.059 +/- 0.004 min(-1).

Affinity chromatography for the purification of therapeutic proteins from transgenic maize using immobilized histamine.

Plant molecular pharming is a technology that uses plants as bioreactors to produce recombinant molecules of medical and veterinary importance. In the present study, we evaluated the ability of histamine (HIM), tryptamine (TRM), phenylamine (PHEM) and tyramine (TYRM) coupled to Sepharose CL-4B via a 1,4-butanediol diglycidyl ether spacer to bind and purify human monoclonal anti-HIV antibody 2F5 (mAb 2F5) from spiked maize seed and tobacco leaf extracts. Detailed studies were carried out to determine the factors that affect the chromatographic behaviour of mAb 2F5 and also maize seed and tobacco leaf proteins. All affinity adsorbents showed a reduced capacity to bind and a reduced ability to purify proteins from tobacco extract compared to maize extract. Under optimal conditions, HIM exhibited high selectivity for mAb 2F5 and allowed a high degree of purification (>95% purity) and recovery (>90%) in a single step with salt elution (0.4 M KCl) from spiked maize seed extract. Analysis of the purified antibody fraction by ELISA and Western blot showed that the antibody was fully active and free of degraded variants or modified forms. The efficacy of the system was assessed further using a second therapeutic antibody (human monoclonal anti-HIV antibody mAb 2G12) and a therapeutic enzyme (alpha-chymotrypsin). HIM may find application in the purification of a wide range of biopharmaceuticals from transgenic plants.

Cost-effective production of a vaginal protein microbicide to prevent HIV transmission.

A series of small-molecule microbicides has been developed for vaginal delivery to prevent heterosexual HIV transmission, but results from human clinical trials have been disappointing. Protein-based microbicides, such as HIV-specific monoclonal antibodies, have been considered as an alternative approach. Despite their promising safety profile and efficacy, the major drawback of such molecules is the economy of large-scale production in mammalian cells, the current system of choice. Here, we show that an alternative biomanufacturing platform is now available for one of the most promising anti-HIV antibodies (2G12). Our data show that the HIV-neutralization capability of the antibody is equal to or superior to that of the same antibody produced in CHO cells. We conclude that this protein production system may provide a means to achieve microbicide ingredient manufacture at costs that would allow product introduction and manufacture in the developing world.

Development of recombinant protein-based influenza vaccine. Expression and affinity purification of H1N1 influenza virus neuraminidase.

The influenza virus surface glycoprotein antigen neuraminidase (NA) is a crucial viral enzyme with many potential medical applications; therefore, the development of efficient upstream and downstream processing strategy for the expression and purification of NA is of high importance. In the present work the NA gene from the H1N1 influenza virus strain A/Beijing/262/95 was cloned from viral RNA and expressed in expresSF+ insect cells using the baculovirus expression vector system (BVES). A limited affinity-ligand library was synthesized and evaluated for its ability to bind and purify the recombinant H1N1 neuraminidase. Affinity-ligand design was based on mimicking the interactions of the lock-and-key (LAK) motif (Phe-Gly-Gln), a common structural moiety found in the subunit interface of glutathione S-transferase I (GST I), and plays an important structural role in subunit-subunit recognition. Solid-phase combinatorial chemistry was used to synthesize 13 variants of the lock-and-key lead ligand (Phe-Trz-X, where X was selected alpha-amino acid) using the 1,3,5-triazine moiety (Trz) as the scaffold for assembly. One immobilized ligand, bearing phenylalanine and isoleucine linked on the chlorotriazine ring (Phe-Trz-Ile), displayed high affinity for NA. Absorption equilibrium and molecular modeling studies were carried out to provide a detailed picture of Phe-Trz-Ile interaction with NA. This LAK-mimetic affinity adsorbent was exploited in the development of a facile purification protocol for NA, which led to 335-fold purification in a single-step. The present purification procedure is the most efficient reported so far for recombinant NA.

Lock-and-key motif as a concept for designing affinity adsorbents for protein purification.

The lock-and-key (LAK) motif, a common structural moiety found in subunit interfaces of glutathione S-transferases (GSTs), plays an important role in biomolecular recognition and quaternary structure integrity. Inspection of the key structural features of the LAK motif prompted the de novo design and combinatorial synthesis of a 13-membered solid-phase ligand library, employing as a lead ligand the Phe-Trz-X structure, mimicking the LAK motif. 1,3,5-Triazine (Trz) was used as the scaffold for assembly, substituted with different LAK-mimetic amino acids. De novo ligand design was effected using bioinformatics and molecular modeling and based on mimicking the interactions of the LAK motif. The library of affinity adsorbents was assessed for binding corn and human serum proteomes and purified proteins of different structure and ligand binding specificity. The results showed remarkable differences in the binding specificity of LAK-mimetic adsorbents for a wide range of proteins, as a consequence of minor changes in ligand structure. One LAK-mimetic adsorbent was integrated in a single-step purification protocol for human monoclonal anti-human immunodeficiency virus 2F5 antibody (mAb 2F5) from spiked corn extract, affording high recovery and purity. The results demonstrate that the principle of natural recognition found in the lock-and-key motif, in combination with de novo combinatorial design, may lead to synthetic affinity ligands, useful in downstream processing and proteomic research.

Development of an aqueous two-phase partitioning system for fractionating therapeutic proteins from tobacco extract.

In the present study, an aqueous two-phase partitioning system (ATPS) was developed and evaluated as an initial fractionation step for therapeutic antibodies and enzymes from tobacco extracts. A detailed study has been performed to analyze the effect of pH, ionic composition of the system, types of polymers and their molecular weight and concentration, on the partitioning behavior of tobacco proteins and human anti-human immunodeficiency virus (HIV) monoclonal antibody 2F5 (mAb 2F5). A polyethyleneglycol/phosphate (PEG/Pi) aqueous two-phase system composed of 12% (w/w) PEG 1500 and 13% (w/w) phosphate buffer, pH 5, was selected as the system with the highest selectivity of antibody over native tobacco proteins. Under selected conditions, sufficient purification (3-4-fold) with high recovery at the bottom phase (approximately 95%) was achieved for mAb 2F5. In addition, the system allows removal of plant-derived compounds, such as phenolics and toxic alkaloids. The antibody fraction may be directly applied to a Protein A affinity column without any further pre-treatment, thus allowing homogenous antibody preparation. Analysis of the purified antibody fraction by enzyme-linked immunosorbent assay (ELISA) and western blot showed that the antibody was fully active and free of degraded variants or modified forms. The efficacy of the system was further demonstrated using additional proteins and enzymes of therapeutic importance, such as neuraminidase (NA) from influenza virus and human anti-HIV monoclonal antibody 2G12 (mAb 2G12), and showed that the system may find wide applicability as an economic extraction strategy for the initial fractionation of biopharmaceuticals from transgenic tobacco plants.

Structure-guided design of a novel class of benzyl-sulfonate inhibitors for influenza virus neuraminidase.

Influenza NA (neuraminidase) is an antiviral target of high pharmaceutical interest because of its essential role in cleaving sialic acid residues from cell surface glycoproteins and facilitating release of virions from infected cells. The present paper describes the use of structural information in the progressive design from a lead binding ion (a sulfate) to a potent submicromolor inhibitor (K(i) 0.13 microM). Structural information derived from the X-ray structure of an NA complexed with several sulfate ions, in combination with results derived from affinity labelling and molecular modelling studies, was used to guide design of potent sulfonic acid-based inhibitors. These inhibitors are structural fragments of the polysulfonate triazine dye Cibacron Blue 3GA and represent novel lead scaffolds for designing non-carbohydrate inhibitors for influenza neuraminidases.

Activity of hybrid type I interferons in cells lacking Tyk2: a common region of IFN-alpha 8 induces a response, but IFN-alpha2/8 hybrids can behave like IFN-beta.

Type I interferons (IFNs) are a family of pleiotropic cytokines with antiviral, antiproliferative, and immunomodulatory properties. The type I IFN family consists of 12 IFN-alpha subtypes, IFN-beta, and IFN-omega. Cells lacking the receptor-associated protein kinase Tyk2 (U1A) are responsive only to IFN-beta and partially to IFN-alpha8. We constructed a series of IFN-alpha2/alpha8 hybrids and mutants and identified the region within IFN-alpha8 responsible for its activity in Tyk2-deficient cells. The same domain mediates the interactions between IFN and IFN-alpha receptor (IFNAR) in Tyk2-complemented and Tyk2-deficient cells (U1A). The presence or absence of Tyk2 altered the inhibitory effects of anti-IFNAR antibodies, suggesting that the IFN-alpha binding domain on IFNAR is altered by the presence of Tyk2. The activity of IFN-beta was not significantly affected by the deletion of Tyk2, and, surprisingly, one of our IFN-alpha2/alpha8 hybrids (IFN-alpha288) behaved like IFN-beta in a number of assays that distinguish IFN-alphas from IFN-beta. This suggests that this hybrid mimics the interactions of IFN-beta with the receptor and also suggests the existence of a distinct binding site(s) on IFNAR for IFN-beta and some hybrid IFN-alphas.

High yield expression, refolding, and characterization of recombinant interferon alpha2/alpha8 hybrids in Escherichia coli.

Interferons (IFNs) are a family of pleiotropic cytokines used for the treatment of various viral infections and cancers. The low-cost production of IFNs with high biological value and the discovery of IFNs with improved properties are important for the treatment of these diseases as well as for understanding the physiological functions of these compounds. We describe a protein expression system for the production of IFNs alpha2, alpha8, and their hybrids in insoluble form in Escherichia coli, coupled to an efficient two-step optimized refolding and histidine-tag purification protocol. The expressed IFNs were of high biological value, as shown in antiviral and antiproliferative assays and some had specific activities higher than those of the commercially available interferon preparations and exhibited novel properties. This time-efficient, optimized protein expression method allows for the production of not just a single interferon subtype but several native and hybrid IFNs with relatively high yield and low cost that can be used in functional and potentially clinical assays.