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1.
Biochem Biophys Res Commun ; 529(2): 257-262, 2020 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-32703420

RESUMO

In the case of a new viral disease outbreak, an immediate development of virus detection kits and vaccines is required. For COVID-19, we established a rapid production procedure for SARS-CoV-2 spike protein (S protein) by using the baculovirus-silkworm expression system. The baculovirus vector-derived S proteins were successfully secreted to silkworm serum, whereas those formed insoluble structure in the larval fat body and the pupal cells. The ectodomain of S protein with the native sequence was cleaved by the host furin-protease, resulting in less recombinant protein production. The S protein modified in furin protease-target site was efficiently secreted to silkworm serum and was purified as oligomers, which showed immunoreactivity for anti-SARS-CoV-2 S2 antibody. By using the direct transfection of recombinant bacmid to silkworms, we achieved the efficient production of SARS-CoV-2 S protein as fetal bovine serum (FBS)-free system. The resultant purified S protein would be useful tools for the development of immunodetection kits, antigen for immunization for immunoglobulin production, and vaccines.


Assuntos
Bombyx/citologia , Bombyx/virologia , Nucleopoliedrovírus/genética , Glicoproteína da Espícula de Coronavírus/biossíntese , Glicoproteína da Espícula de Coronavírus/isolamento & purificação , Animais , Bombyx/enzimologia , Linhagem Celular , Clonagem Molecular , Furina/metabolismo , Nucleopoliedrovírus/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética
2.
Anal Chem ; 92(16): 10930-10934, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32678978

RESUMO

The emergence and rapid proliferation of the novel coronavirus (SARS-CoV-2) resulted in a global pandemic, with over 6,000,000 cases and nearly 400,000 deaths reported worldwide by the end of May 2020. A rush to find a cure prompted re-evaluation of a range of existing therapeutics vis-à-vis their potential role in treating COVID-19, placing a premium on analytical tools capable of supporting such efforts. Native mass spectrometry (MS) has long been a tool of choice in supporting the mechanistic studies of drug/therapeutic target interactions, but its applications remain limited in the cases that involve systems with a high level of structural heterogeneity. Both SARS-CoV-2 spike protein (S-protein), a critical element of the viral entry to the host cell, and ACE2, its docking site on the host cell surface, are extensively glycosylated, making them challenging targets for native MS. However, supplementing native MS with a gas-phase ion manipulation technique (limited charge reduction) allows meaningful information to be obtained on the noncovalent complexes formed by ACE2 and the receptor-binding domain (RBD) of the S-protein. Using this technique in combination with molecular modeling also allows the role of heparin in destabilizing the ACE2/RBD association to be studied, providing critical information for understanding the molecular mechanism of its interference with the virus docking to the host cell receptor. Both short (pentasaccharide) and relatively long (eicosasaccharide) heparin oligomers form 1:1 complexes with RBD, indicating the presence of a single binding site. This association alters the protein conformation (to maximize the contiguous patch of the positive charge on the RBD surface), resulting in a notable decrease in its ability to associate with ACE2. The destabilizing effect of heparin is more pronounced in the case of the longer chains due to the electrostatic repulsion between the low-pI ACE2 and the heparin segments not accommodated on the RBD surface. In addition to providing important mechanistic information on attenuation of the ACE2/RBD association by heparin, the study demonstrates the yet untapped potential of native MS coupled to gas-phase ion chemistry as a means of facilitating rational repurposing of the existing medicines for treating COVID-19.


Assuntos
Infecções por Coronavirus/patologia , Heparina/metabolismo , Espectrometria de Massas/métodos , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/patologia , Betacoronavirus/isolamento & purificação , Betacoronavirus/metabolismo , Sítios de Ligação , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/virologia , Gases/química , Heparina/farmacologia , Heparina/uso terapêutico , Humanos , Simulação de Dinâmica Molecular , Pandemias , Peptidil Dipeptidase A/química , Peptidil Dipeptidase A/genética , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/virologia , Ligação Proteica , Domínios Proteicos , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Internalização do Vírus/efeitos dos fármacos
3.
PLoS One ; 15(7): e0235687, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32678825

RESUMO

Lactobacillus amylolyticus L6, a gram-positive amylolytic bacterium isolated from naturally fermented tofu whey (NFTW), was able to hydrolyze raffinose and stachyose for the production of α-galactosidase. The cell-free extract of L. amylolyticus L6 was found to exhibit glycosyltransferase activity to synthesize α-galacto-oligosaccharides (GOS) with melibiose as substrate. The coding genes of α-galactosidase were identified in the genome of L. amylolyticus L6. The α-galactosidase (AglB) was placed into GH36 family by amino acid sequence alignments with other α-galactosidases from lactobacilli. The optimal reaction conditions of pH and temperature for AglB were pH 6.0 and 37°C, respectively. Besides, potassium ion was found to improve the activity of AglB while divalent mercury ion, copper ion and zinc ion displayed different degrees of inhibition effect. Under the optimum reaction condition, AglB could catalyze the synthesis of GOS with degree of polymerization (DP) ≥5 by using 300 mM melibiose concentration as substrate. The maximum yield of GOS with (DP) ≥3 could reach 31.56% (w/w). Transgalactosyl properties made AglB a potential candidate for application in the production of GOS.


Assuntos
Proteínas de Bactérias/metabolismo , Clonagem Molecular , Lactobacillus/enzimologia , alfa-Galactosidase/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Estabilidade Enzimática , Glicosilação , Concentração de Íons de Hidrogênio , Hidrólise , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Alinhamento de Sequência , Temperatura , alfa-Galactosidase/química , alfa-Galactosidase/genética
4.
PLoS One ; 15(6): e0231679, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32559193

RESUMO

The envelope glycoprotein (Env) of the human immunodeficiency virus (HIV), has been the primary target for the development of a protective vaccine against infection. The extensive N-linked glycosylation on Env is an important consideration as it may affect efficacy, stability, and expression yields. The expression host has been shown to influence the extent and type of glycosylation that decorates the protein target. Here, we report the glycosylation profile of the candidate subtype C immunogen CO6980v0c22 gp145, which is currently in Phase I clinical trials, produced in two different host cells: CHO-K1 and Expi293F. The amino acid sequence for both glycoproteins was confirmed to be identical by peptide mass fingerprinting. However, the isoelectric point of the proteins differed; 4.5-5.5 and 6.0-7.0 for gp145 produced in CHO-K1 and Expi293F, respectively. These differences in pI were eliminated by enzymatic treatment with sialidase, indicating a large difference in the incorporation of sialic acid between hosts. This dramatic difference in the number of sialylated glycans between hosts was confirmed by analysis of PNGase F-released glycans using MALDI-ToF MS. These differences in glycosylation, however, did not greatly translate into differences in antibody recognition. Biosensor assays showed that gp145 produced in CHO-K1 had similar affinity toward the broadly neutralizing antibodies, 2G12 and PG16, as the gp145 produced in Expi293F. Additionally, both immunogens showed the same reactivity against plasma of HIV-infected patients. Taken together, these results support the notion that there are sizeable differences in the glycosylation of Env depending on the expression host. How these differences translate to vaccine efficacy remains unknown.


Assuntos
Glicopeptídeos/análise , Anticorpos Anti-HIV/imunologia , HIV-1/metabolismo , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Adulto , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Reações Antígeno-Anticorpo , Células CHO , Cricetinae , Cricetulus , Feminino , Glicosilação , Células HEK293 , Humanos , Pessoa de Meia-Idade , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Adulto Jovem , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética , Produtos do Gene env do Vírus da Imunodeficiência Humana/metabolismo
5.
Nan Fang Yi Ke Da Xue Xue Bao ; 40(1): 67-72, 2020 Jan 30.
Artigo em Chinês | MEDLINE | ID: mdl-32376560

RESUMO

OBJECTIVE: The obtain purified recombinant asprosin and test its functions. METHODS: The recombinant plasmid of pET-22b-asprosin was constructed and transformed into competent E.coli BL (DE3) strain. After IPTG-induced expression, asprosin inclusion body was renatured by gradient urea and purified by Ni-NTA affinity chromatography column followed by removal of endotoxin to obtain recombinant asprosin for use in cells and animals experiments. C57 mice were injected intraperitoneally with the recombinant asprosin and blood glucose was detected using a blood glucose meter. Alamar Blue assay was used to evaluate of the effect of the recombinant asprosin on the viability of MIHA cells, and cellular glycogen content was detected using the anthrone method. RESULTS: At the absorbance at 600 nm of 0.8, induction of the recombinant host bacteria with 1 mmol/L IPTG at 37 ℃ for 4 h optimally induced the expression of asprosin inclusion body. After purification and endotoxin removal, the purity of the recombinant asprosin exceeded 95% with the content of endotoxin below 1 EU/mg. In C57 mice, intraperitoneal injection with recombinant asprosin significantly increased blood glucose level, which reached the peak level at 60 min following the injection (P=0.021) and recovered the normal level at 120 min (P=0.03). Treatment with the recombinant asprosin for 24 h did not cause obvious adverse effect on the viability of MIHA cells but significantly lowered glycogen content in the cells (P < 0.05). CONCLUSIONS: We successfully obtained recombinant asprosin using a prokaryotic expression system. The recombinant asprosin can decrease glycogen content in MIHA cells and increase blood glucose level in mice.


Assuntos
Corpos de Inclusão , Proteínas dos Microfilamentos/biossíntese , Fragmentos de Peptídeos/biossíntese , Hormônios Peptídicos/biossíntese , Animais , Glicemia/análise , Linhagem Celular , Escherichia coli , Glicogênio/análise , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Plasmídeos , Proteínas Recombinantes/biossíntese
6.
PLoS One ; 15(5): e0233492, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32469948

RESUMO

Glycosylation can affect various protein properties such as stability, biological activity, and immunogenicity. To produce human therapeutic proteins, a host that can produce glycoproteins with correct glycan structures is required. Microbial expression systems offer economical, rapid and serum-free production and are more amenable to genetic manipulation. In this study, we developed a protocol for CRISPR/Cas9 multiple gene knockouts and knockins in Kluyveromyces marxianus, a probiotic yeast with a rapid growth rate. As hyper-mannosylation is a common problem in yeast, we first knocked out the α-1,3-mannosyltransferase (ALG3) and α-1,6-mannosyltransferase (OCH1) genes to reduce mannosylation. We also knocked out the subunit of the telomeric Ku domain (KU70) to increase the homologous recombination efficiency of K. marxianus. In addition, we knocked in the MdsI (α-1,2-mannosidase) gene to reduce mannosylation and the GnTI (ß-1,2-N-acetylglucosaminyltransferase I) and GnTII genes to produce human N-glycan structures. We finally obtained two strains that can produce low amounts of the core N-glycan Man3GlcNAc2 and the human complex N-glycan Man3GlcNAc4, where Man is mannose and GlcNAc is N-acetylglucosamine. This study lays a cornerstone of glycosylation engineering in K. marxianus toward producing human glycoproteins.


Assuntos
Kluyveromyces/genética , Kluyveromyces/metabolismo , Engenharia Metabólica/métodos , Polissacarídeos/biossíntese , Polissacarídeos/química , Biotecnologia , Sistemas CRISPR-Cas , Técnicas de Introdução de Genes , Técnicas de Inativação de Genes , Genes Fúngicos , Glicoproteínas/biossíntese , Glicoproteínas/química , Glicoproteínas/genética , Glicosilação , Humanos , Manosidases/genética , Manosidases/metabolismo , Manosiltransferases/antagonistas & inibidores , Manosiltransferases/genética , Manosiltransferases/metabolismo , N-Acetilglucosaminiltransferases/genética , N-Acetilglucosaminiltransferases/metabolismo , Polissacarídeos/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/genética
7.
PLoS One ; 15(5): e0232661, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32379796

RESUMO

Platelet factor 4 is a cytokine released into the bloodstream by activated platelets where it plays a pivotal role in etiology and diagnosis of heparin-induced thrombocytopenia. Therefore, a sustainable source of recombinant PF4 with structural and functional similarity to its native form is urgently needed to be used in diagnostic procedures. To this end, a three-in-one primary construct was designed from which three secondary constructs can be derived each capable of employing either type I, type II secretory or cytoplasmic pathways. Protein expression and secretion were performed in Escherichia coli BL21 (DE3) and confirmed by SDS-PAGE and Western blotting. To further enhance protein secretion, the effect of several controllable chemical factors including IPTG, Triton X-100, sucrose, and glycine were individually investigated at the outset. In the next step, according to a fractional factorial approach, the synergistic effects of IPTG, Triton X-100, and glycine on secretion were further investigated. To ascertain the structure and function of the secreted recombinant proteins, dynamic light scattering was utilized to confirm the rPF4 tetramerization and heparin-mediated ultra-large complex formation. Moreover, Raman spectroscopy and Western blotting were exploited to evaluate the secondary and quaternary structures, respectively. The type II secretory pathway was proven to be superior to type I in the case of rPF4 secretion. Supplementation with chemical enhancers improved the protein secretion mediated by the Type II system to approximately more than 500 µg/mL. Large quantities of native rPF4 up to 20 mg were purified as the culture medium was scaled up to 40 mL. Western blotting confirmed the formation of dimers and tetramers in the secreted rPF4 proteins. Dynamic light scattering revealed the rPF4 oligomerization into of larger complexes of approximately 100-1200 nm in size following heparin supplementation, implying proper protein folding and tetramerization. Moreover, the rPF4 secondary structure was found to be 43.5% Random coil, 32.5% ß-sheet, 18.6% α-helix and 4.9% Turn, which is in perfect agreement with the native structure. Our results indicate that the gram-negative type II bacterial secretory system holds a great promise as a reliable protein production strategy with industrial applications. However, further efforts are required to realize the full potential of secretory pathways regarding their application to proteins with distinct characteristics.


Assuntos
Fator Plaquetário 4/biossíntese , Fator Plaquetário 4/isolamento & purificação , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Sistemas de Secreção Tipo II , Clonagem Molecular , Escherichia coli/genética
8.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 36(3): 264-270, 2020 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-32389175

RESUMO

Objective To express E6 protein of human papillomavirus (HPV) type 16 in prokaryotic expression system and prepare its polyclonal antibody. Methods HPV16 E6 gene was obtained from Siha cells by PCR and cloned into pET21a(+) vector to construct the recombinant plasmid pET21a(+)/HPV16 E6 that was confirmed by sequencing. The recombinant plasmid pET21a(+)/HPV16 E6 was transformed into E. coli BL21 (DE3). The HPV16 E6-His tag recombinant protein was expressed after the induction of isopropyl beta-D-1-thiogalactopyranoside (IPTG), purified by Ni-NTA affinity chromatography, and then analyzed by Western blot analysis. The purified HPV16 E6 recombinant protein was used to immunize Japanese white rabbits to prepare polyclonal antibody. The titer of the serum polyclonal antibody was determined by ELISA. The specificity of the polyclonal antibody was analyzed by Western blotting and immunofluorescence. Results The recombinant plasmid pET21a(+)/HPV16 E6 was successfully constructed and confirmed by sequencing. After the recombinant plasmid pET21a(+)/HPV16 E6 was transformed into E. coli BL21 (DE3), the recombinant HPV16 E6 protein was expressed and purified by affinity chromatography. The polyclonal antibody at a titer of 1:40 000 was obtained by immunizing Japanese big-ear white rabbit with the purified recombinant HPV16 E6 protein, and its specificity was confirmed by Western blotting and immunofluorescence assay. Conclusion HPV16 E6 recombinant protein was successfully expressed and the rabbit polyclonal antibody against HPV16 E6 recombinant protein was prepared.


Assuntos
Anticorpos/imunologia , Proteínas Oncogênicas Virais/biossíntese , Proteínas Oncogênicas Virais/imunologia , Proteínas Repressoras/biossíntese , Proteínas Repressoras/imunologia , Animais , Especificidade de Anticorpos , Western Blotting , Ensaio de Imunoadsorção Enzimática , Escherichia coli , Plasmídeos , Coelhos , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/imunologia
9.
Sheng Wu Gong Cheng Xue Bao ; 36(4): 750-762, 2020 Apr 25.
Artigo em Chinês | MEDLINE | ID: mdl-32347069

RESUMO

PEGylation is considered one of the most successful techniques to improve the characteristics of protein drugs including to increase the circulating half-life of proteins in blood and to decrease their immunogenicity and antigenicity. One known PEG modification method is to attach PEG to the free amino group, typically at lysine residues or at the N-terminal amino acid with no selectivity, resulting in a heterogeneous product mixture. This lack of selectivity can present problems when a therapeutic PEGylated protein is being developed, because predictability of activity and manufacturing reproducibility are needed for regulatory approval. Enzymatic PEGylation of proteins is one route to overcome this limitation. Transglutaminases (TGase) are enzyme candidates for site-specific PEGylation. We use human interferon alpha 2a (IFN α2a) as a test case, and predict that the potential modification residues are Gln101 by computational approach as it contains 12 potential PEGylation sites. IFN α2a was PEGylated by Y shaped PEG40k-NH2 mediated by microbial transglutaminase. Our results show that the microbial transglutaminase mediated PEGylation of IFN α2a was site-specific only at the site of Gln101 in IFN α2a, yielding the single mono-conjugate PEG-Gln101-IFN α2a with a mass of 59 374.66 Da. Circular dichroism studies showed that PEG-Gln101-IFN α2a preserved the same secondary structures as native IFN α2a. As expected, the bioactivity and pharmacokinetic profile in rats of PEG-Gln101-IFN α2a revealed a significant improvement to unmodified IFN α2a, and better than PEGASYS.


Assuntos
Antivirais , Interferon-alfa , Polietilenoglicóis , Transglutaminases , Animais , Humanos , Interferon alfa-2/metabolismo , Interferon-alfa/biossíntese , Interferon-alfa/farmacocinética , Polietilenoglicóis/farmacocinética , Estrutura Secundária de Proteína , Ratos , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/farmacocinética , Proteínas Recombinantes/farmacologia , Reprodutibilidade dos Testes , Transglutaminases/metabolismo
10.
Arch Virol ; 165(6): 1441-1444, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32239294

RESUMO

Bovine papillomavirus type 9 (BPV9) is a causative agent of severe teat papillomatosis. Considering the lack of efficient BPV culture methods, recombinant proteins such as virus-like particles developed through genetic engineering may serve as a useful tool for developing effective vaccines against BPV infection. In this study, we successfully produced immunogenic particles composed of recombinant L1 protein of BPV9 (rBPV9-L1), using a baculovirus expression system. rBPV9-L1-immunized mice produced BPV9-specific IgG, which did not cross-react with BPV type 6, which is another causative agent of teat papillomatosis. Hence, immunogenic rBPV9-L1 is potentially applicable as a vaccine candidate for teat papillomatosis.


Assuntos
Proteínas do Capsídeo/imunologia , Doenças dos Bovinos/prevenção & controle , Papillomaviridae/imunologia , Infecções por Papillomavirus/veterinária , Vacinas de Partículas Semelhantes a Vírus/imunologia , Animais , Proteínas do Capsídeo/biossíntese , Bovinos , Doenças dos Bovinos/virologia , Feminino , Genótipo , Camundongos , Papillomaviridae/genética , Infecções por Papillomavirus/prevenção & controle , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/imunologia , Vacinação
11.
PLoS One ; 15(4): e0231414, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32267882

RESUMO

Mollusc shells are produced from calcified skeletons and have excellent mechanical properties. Shell matrix proteins (SMPs) have important functions in shell formation. A 16.6 kDa whirlin-like protein (WLP) with a PDZ domain was identified in the shell of Mytilus coruscus as a novel SMP. In this study, the expression, function, and location of WLP were analysed. The WLP gene was highly expressed and specifically located in the adductor muscle and mantle. The expression of recombinant WLP (rWLP) was associated with morphological change, polymorphic change, binding ability, and crystallization rate inhibition of the calcium carbonate crystals in vitro. In addition, an anti-rWLP antibody was prepared, and the results from immunohistochemistry and immunofluorescence analyses revealed the specific location of the WLP in the mantle, adductor muscle, and myostracum layer of the shell, suggesting multiple functions for WLP in biomineralization, muscle-shell attachment, and muscle attraction. Furthermore, results from a pull-down analysis revealed 10 protein partners of WLP in the shell matrices and a possible network of interacting WLPs in the shell. In addition, in this study, one of the WLP partners, actin, was confirmed to have the ability to bind WLP. These results expand the understanding of the functions of PDZ-domain-containing proteins in biomineralization and provide clues for determining the mechanisms of myostracum formation and muscle-shell attachment.


Assuntos
Proteínas de Membrana/metabolismo , Mytilus/metabolismo , Sequência de Aminoácidos , Exoesqueleto/metabolismo , Exoesqueleto/ultraestrutura , Animais , Biomineralização , Carbonato de Cálcio/química , Carbonato de Cálcio/metabolismo , Imuno-Histoquímica , Hibridização In Situ , Proteínas de Membrana/química , Proteínas de Membrana/genética , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Ligação Proteica , Estrutura Secundária de Proteína , Proteômica , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia
12.
PLoS One ; 15(4): e0231344, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32324770

RESUMO

BACKGROUND: Cross-reactive carbohydrate determinant (CCD) structures found in plant and insect glycoproteins are commonly recognized by IgE antibodies as epitopes that can lead to extensive cross-reactivity and obscure in vitro diagnostic (IVD) serology results. With the introduction of component resolved diagnosis (CRD), recombinant non-glycosylated components have been utilized to mitigate the risk of CCD-specific IgE (sIgE) detection. However, a recent study has shown that CCD-sIgE may bind directly to the cellulose solid phase matrix used in certain in vitro diagnostic assays, eliminating the advantage of CRD over traditional extract-based testing. The aim of this study is to further investigate the prevalence of CCD-sIgE interference on a commonly-used in vitro sIgE automated platform which employs a cellulose-based matrix to immobilize CCD-free recombinant components. METHODS: Sera from patients sensitized to peanut, silver birch, and/or timothy grass were analyzed for CCD-sIgE reactivity on ImmunoCAP/Phadia and NOVEOS autoanalyzers against the MUXF3 carbohydrate component. Positive CCD-sIgE sera were further analyzed against non-glycosylated recombinant components bound to the ImmunoCAP solid phase in the absence and presence of a soluble CCD inhibitor. For comparison, sera were then analyzed on NOVEOS, a non-cellulose based automated sIgE assay. RESULTS: Sera from 35% of the sensitized population tested in this study were positive (≥0.35 kU/L) for CCD-sIgE. Of those positives, 17% resulted in CCD-sIgE-positive (false positive) results on ImmunoCAP using non-glycosylated allergosorbents that were negative on NOVEOS. Sera producing false-positive results on ImmunoCAP had varying levels of CCD-sIgE from 0.67 kU/L to 36.52 kU/L. The incidence of CCD interference was predominantly delimited to low-positive IgE results (0.35 kUA/L- 3.00 kUA/L). CONCLUSION: Falsely elevated diagnostic allergen-sIgE results can commonly occur due to the presence of CCD-sIgE using assays that employ a carbohydrate matrix-based allergosorbent. Even the use of non-glycosylated recombinant allergenic components coupled to cellulose matrices do not reduce their risk of detection. The risk of CCD interference that compromises quantitative IgE results can be mitigated by the addition of a soluble CCD inhibitor to positive CCD-sIgE containing sera or by alternatively using a non-cellulose based sIgE assay, such as the NOVEOS assay.


Assuntos
Alérgenos/imunologia , Celulose/imunologia , Imunoglobulina E/imunologia , Alérgenos/genética , Alérgenos/metabolismo , Arachis/imunologia , Betula/imunologia , Reações Cruzadas , Humanos , Hipersensibilidade/sangue , Hipersensibilidade/patologia , Imunoglobulina E/sangue , Phleum/imunologia , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/imunologia
13.
J Biosci Bioeng ; 130(2): 205-211, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32284303

RESUMO

Antibody Fab fragments consist of heavy chain (Hc) and light chain (Lc) polypeptides assembled with a disulphide bond. The production of a recombinant Fab fragment requires the simultaneous expression of two genes encoding both an Hc and an Lc in the same host cell. In the present study, we investigated the production of Fab fragments in lepidopteran insect cells using a bicistronic plasmid vector carrying the Hc and Lc genes linked with a 2A self-cleaving peptide sequence from the porcine teschovirus-1. We also examined the arrangement of a GSG spacer sequence and a furin cleavage site sequence with the 2A sequence. Western blot analysis and enzyme-linked immunosorbent assay (ELISA) of culture supernatants showed that Trichoplusia ni BTI-TN-5B1-4 (High Five) cells transfected with a plasmid in which the Hc and Lc genes were joined by the 2A sequence successfully secreted Fab fragments with antigen-binding activity after self-cleavage of the 2A peptide. The GSG linker enhanced 2A cleavage efficiency, and the furin recognition site was useful for removal of 2A residues from the Hc. Transfection with a single plasmid that contained sequences for GSG, the furin cleavage site, GSG, and the 2A peptide between the Hc and Lc genes exhibited a higher productivity than co-transfection with a set of plasmids separately carrying the Hc or Lc gene. These results demonstrate that bicistronic expression with the appropriate combination of a furin recognition site, GSG linkers, and a 2A peptide may be an effective way to efficiently produce recombinant antibody molecules in insect cells.


Assuntos
Fragmentos Fab das Imunoglobulinas/biossíntese , Proteínas Recombinantes/biossíntese , Sequência de Aminoácidos , Animais , Western Blotting , Linhagem Celular , Ensaio de Imunoadsorção Enzimática , Vetores Genéticos/genética , Humanos , Fragmentos Fab das Imunoglobulinas/genética , Insetos/citologia , Peptídeos/metabolismo , Plasmídeos/genética , Proteínas Recombinantes/genética , Teschovirus/genética , Transfecção
14.
Nat Commun ; 11(1): 1908, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313013

RESUMO

Host cell proteins (HCPs) are process-related impurities generated during biotherapeutic protein production. HCPs can be problematic if they pose a significant metabolic demand, degrade product quality, or contaminate the final product. Here, we present an effort to create a "clean" Chinese hamster ovary (CHO) cell by disrupting multiple genes to eliminate HCPs. Using a model of CHO cell protein secretion, we predict that the elimination of unnecessary HCPs could have a non-negligible impact on protein production. We analyze the HCP content of 6-protein, 11-protein, and 14-protein knockout clones. These cell lines exhibit a substantial reduction in total HCP content (40%-70%). We also observe higher productivity and improved growth characteristics in specific clones. The reduced HCP content facilitates purification of a monoclonal antibody. Thus, substantial improvements can be made in protein titer and purity through large-scale HCP deletion, providing an avenue to increased quality and affordability of high-value biopharmaceuticals.


Assuntos
Engenharia Metabólica/métodos , Proteínas Recombinantes/biossíntese , Animais , Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais/isolamento & purificação , Produtos Biológicos , Células CHO , Cromatografia , Cricetulus , Técnicas de Inativação de Genes , Sequenciamento de Nucleotídeos em Larga Escala , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Rituximab , Biologia Sintética
15.
BMC Infect Dis ; 20(1): 185, 2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32111171

RESUMO

BACKGROUND: Staphylococcus aureus (S. aureus) arthritis is one of the most detrimental joint diseases known and leads to severe joint destruction within days. We hypothesized that the provision of auxiliary immunoregulation via an expanded compartment of T regulatory cells (Tregs) could dampen detrimental aspects of the host immune response whilst preserving its protective nature. Administration of low-dose interleukin 2 (IL2) preferentially expands Tregs, and is being studied as a treatment choice in several autoimmune conditions. We aimed to evaluate the role of IL2 and Tregs in septic arthritis using a well-established mouse model of haematogenously spred S. aureus arthritis. METHODS: C57BL/6 or NMRI mice we intravenously (iv) injected with a defined dose of S. aureus LS-1 or Newman and the role of IL2 and Tregs were assessed by the following approaches: IL2 was endogenously delivered by intraperitoneal injection of a recombinant adeno-associated virus vector (rAAV) before iv S. aureus inoculation; Tregs were depleted before and during S. aureus arthritis using antiCD25 antibodies; Tregs were adoptively transferred before induction of S. aureus arthritis and finally, recombinant IL2 was used as a treatment starting day 3 after S. aureus injection. Studied outcomes included survival, weight change, bacterial clearance, and joint damage. RESULTS: Expansion of Tregs induced by IL2 gene therapy prior to disease onset does not compromise host resistance to S. aureus infection, as the increased proportions of Tregs reduced the arthritis severity as well as the systemic inflammatory response, while simultaneously preserving the host's ability to clear the infection. CONCLUSIONS: Pre-treatment with IL2 gene therapy dampens detrimental immune responses but preserves appropriate host defense, which alleviates S. aureus septic arthritis in a mouse model.


Assuntos
Artrite Infecciosa/prevenção & controle , Terapia Genética , Interleucina-2/genética , Staphylococcus aureus/patogenicidade , Animais , Anticorpos Monoclonais/uso terapêutico , Artrite Infecciosa/etiologia , Dependovirus/genética , Modelos Animais de Doenças , Feminino , Vetores Genéticos/metabolismo , Interleucina-2/metabolismo , Subunidade alfa de Receptor de Interleucina-2/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/uso terapêutico , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo
16.
PLoS One ; 15(3): e0230021, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32160226

RESUMO

Supplementing chicken feed with antibiotics can improve survival and prevent disease outbreaks. However, overuse of antibiotics may promote the development of antibiotic-resistant bacteria. Recently, antimicrobial peptides have been proposed as alternatives to antibiotics in animal husbandry. Here, we evaluate the effects of antimicrobial peptide, Epinephelus lanceolatus piscidin (EP), in Gallus gallus domesticus. The gene encoding EP was isolated, sequenced, codon-optimized and cloned into a Pichia pastoris recombinant protein expression system. The expressed recombinant EP (rEP) was then used as a dietary supplement for G. g. domesticus; overall health, growth performance and immunity were assessed. Supernatant from rEP-expressing yeast showed in vitro antimicrobial activity against Gram-positive and Gram-negative bacteria, according to an inhibition-zone diameter (mm) assay. Moreover, the antimicrobial peptide function of rEP was temperature independent. The fermentation broth yielded a spray-dried powder formulation containing 262.9 µg EP/g powder, and LC-MS/MS (tandem MS) analysis confirmed that rEP had a molecular weight of 4279 Da, as expected for the 34-amino acid peptide; the DNA sequence of the expression vector was also validated. We then evaluated rEP as a feed additive for G. g. domesticus. Treatment groups included control, basal diet and rEP at different doses (0.75, 1.5, 3.0, 6.0 and 12%). Compared to control, rEP supplementation increased G. g. domesticus weight gain, feed efficiency, IL-10 and IFN-γ production. Our results suggest that crude rEP could provide an alternative to traditional antibiotic feed additives for G. g. domesticus, serving to enhance growth and health of the animals.


Assuntos
Peptídeos Catiônicos Antimicrobianos/metabolismo , Galinhas/imunologia , Sistema Imunitário/metabolismo , Perciformes/metabolismo , Sequência de Aminoácidos , Animais , Anti-Infecciosos/análise , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/análise , Peptídeos Catiônicos Antimicrobianos/classificação , Peptídeos Catiônicos Antimicrobianos/genética , Galinhas/crescimento & desenvolvimento , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , Suplementos Nutricionais , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Sistema Imunitário/efeitos dos fármacos , Interferon gama/metabolismo , Interleucina-10/metabolismo , Filogenia , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/farmacologia , Alinhamento de Sequência , Espectrometria de Massas em Tandem , Temperatura
17.
PLoS One ; 15(3): e0230682, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32210456

RESUMO

Atherosclerosis is a chronic inflammatory disease and major cause of mortality worldwide. One of the crucial steps for atherosclerotic plaque development is oxidation of low-density lipoprotein (LDL). Through the oxidation, highly immunogenic epitopes are created and the immune system is activated. Association between atherosclerosis and periodontal diseases is well documented, and one of the main oral pathogens common in periodontitis is Aggregatibacter actinomycetemcomitans (Aa). Heat shock protein 60 (HSP60) is an important virulence factor for Aa bacteria and a strong activator of the immune system. Cross-reactivity of HSP60 and oxidized LDL (OxLDL) antibodies could be a potential mechanism in the progression of atherosclerosis and one possible link between atherosclerosis and periodontitis. Human plasma samples from neonates and mothers were analyzed to determine if antibody titer to Aa-HSP60 protein is already present in newborns. Further objectives were to characterize antibody response in Aa-HSP60 immunized mice and to determine possible antibody cross-reaction with oxidized LDL. We demonstrated that newborns already have IgM antibody levels to Aa-HSP60. We also showed that in mice, Aa-HSP60 immunization provoked IgG and IgM antibody response not only to Aa-HSP60 but also to malondialdehyde acetaldehyde-modified LDL (MAA-LDL). Competition assay revealed that the antibodies were specific to Aa-HSP60 and cross-reacted with MAA-LDL. Our results suggest a possibility of molecular mimicry between Aa-HSP60 and MAA-LDL, making it intriguing to speculate on the role of HSP60 protein in atherosclerosis that manifests at young age.


Assuntos
Aggregatibacter actinomycetemcomitans/metabolismo , Chaperonina 60/imunologia , Imunidade Humoral , Lipoproteínas LDL/imunologia , Aggregatibacter actinomycetemcomitans/imunologia , Animais , Reações Antígeno-Anticorpo , Chaperonina 60/genética , Chaperonina 60/metabolismo , Reações Cruzadas , Feminino , Sangue Fetal/metabolismo , Humanos , Imunoensaio , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia
18.
Biochim Biophys Acta Biomembr ; 1862(6): 183272, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32169592

RESUMO

Membrane proteins exist in lipid bilayers and mediate solute transport, signal transduction, cell-cell communication and energy conversion. Their activities are fundamental for life, which make them prominent subjects of study, but access to only a limited number of high-resolution structures complicates their mechanistic understanding. The absence of such structures relates mainly to difficulties in expressing and purifying high quality membrane protein samples in large quantities. An additional layer of complexity stems from the presence of intra- and/or extra-cellular domains constituted by unstructured intrinsically disordered regions (IDR), which can be hundreds of residues long. Although IDRs form key interaction hubs that facilitate biological processes, these are regularly removed to enable structural studies. To advance mechanistic insight into intact intrinsically disordered membrane proteins, we have developed a protocol for their purification. Using engineered yeast cells for optimized expression and purification, we have purified to homogeneity two very different human membrane proteins each with >300 residues long IDRs; the sodium proton exchanger 1 and the growth hormone receptor. Subsequent to their purification we have further explored their incorporation into membrane scaffolding protein nanodiscs, which will enable future structural studies.


Assuntos
Proteínas Intrinsicamente Desordenadas/química , Proteínas de Membrana/química , Proteínas Recombinantes/química , Saccharomyces cerevisiae/genética , Humanos , Proteínas de Membrana/biossíntese , Conformação Proteica , Receptores da Somatotropina/química , Proteínas Recombinantes/biossíntese , Trocadores de Sódio-Hidrogênio/química , Leveduras/genética
19.
Cell Physiol Biochem ; 54(1): 126-141, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32017483

RESUMO

BACKGROUND/AIMS: Serotonin (5-hydroxytryptamine, 5-HT) is a neurotransmitter and hormone with important physiological functions in many organs, including the intestine. We have previously shown that 5-HT activates the aryl hydrocarbon receptor (AhR) in intestinal epithelial cells (IECs) via a serotonin transporter (SERT)-dependent mechanism. AhR is a nuclear receptor that binds a variety of molecules including tryptophan (TRP) metabolites to regulate physiological processes in the intestine including xenobiotic detoxification and immune modulation. We hypothesized that 5-HT activates AhR indirectly by interfering with metabolic clearance of AhR ligands by cytochrome P450 1A1 (CYP1A1). METHODS: Inhibition of CYP1A1 activity by 5-HT was assessed in the human intestinal epithelial cell line Caco-2 and recombinant CYP1A1 microsomes using both luciferase and LC-MS/MS. Degradation of 5-HT by recombinant CYP1A1 was measured by LC-MS/MS. For in vitro studies, CYP1A1 and CYP1B1 mRNA expression levels were measured by RT-PCR and CYP1A1 activity was measured by ethoxyresorufin-O-deethylase (EROD) assays. For in vivo studies, AhR ligands were administered to SERT KO mice and WT littermates and intestinal mucosa CYP1A1 mRNA was measured. RESULTS: We show that 5-HT inhibits metabolism of both the pro-luciferin CYP1A1 substrate Luc-CEE as well as the high affinity AhR ligand 6-formylindolo[3,2-b] carbazole (FICZ). Recombinant CYP1A1 assays revealed that 5-HT is metabolized by CYP1A1 in an NADPH dependent manner. Treatment with 5-HT in TRP-free medium, which is devoid of trace AhR ligands, showed that 5-HT requires the presence of AhR ligands to activate AhR. Cotreatment with 5-HT and FICZ confirmed that 5-HT potentiates induction of AhR target genes by AhR ligands. However, this was only true for ligands which are CYP1A1 substrates such as FICZ. Administration of ß-napthoflavone by gavage or indole-3-carbinol via diet to SERT KO mice revealed that lack of SERT impairs intestinal AhR activation. CONCLUSION: Our studies provide novel evidence of crosstalk between serotonergic and AhR signaling where 5-HT can influence the ability of AhR ligands to activate the receptor in the intestine.


Assuntos
Citocromo P-450 CYP1A1/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Serotonina/farmacologia , Transcrição Genética/efeitos dos fármacos , Animais , Células CACO-2 , Carbazóis/farmacologia , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1B1/genética , Citocromo P-450 CYP1B1/metabolismo , Humanos , Ligantes , Masculino , Camundongos , Camundongos Knockout , RNA Mensageiro/metabolismo , Receptores de Hidrocarboneto Arílico/química , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Proteínas da Membrana Plasmática de Transporte de Serotonina/deficiência , Proteínas da Membrana Plasmática de Transporte de Serotonina/genética , Transdução de Sinais/efeitos dos fármacos , Especificidade por Substrato , beta-Naftoflavona/administração & dosagem
20.
Photochem Photobiol Sci ; 19(2): 274-280, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32002529

RESUMO

In the present study, we aimed to purify and characterize LuxG obtained from Photobacterium leiognathi YL and examine its improvement for NADH detection. To this end, we cloned and expressed the putative luxG gene of P. leiognathi YL in the Escherichia coli BL21 strain. The product of luxG is a flavin reductase that consists of 206 amino acids, corresponding to a subunit molecular mass of ∼26 kDa. Phylogenetic analysis demonstrated that P. leiognathi YL LuxG has a rather distant evolutionary relationship with Frase I of Aliivibrio fischeri and Frp of Vibrio harveyi, but a close evolutionary relationship with Fre from Escherichia coli, which are all enzymes related to oxido-reductase. Further comparison shows that the changes in the functionally conserved sites may contribute to the functional divergence of LuxG and Fre. LuxG could supply reduced flavin mononucleotide (FMN) for bacterial luminescence by catalyzing the oxidation of nicotinamide adenine dinucleotide hydrogen (NADH). Based on this, a coupled pure enzyme bioluminescent system was established and used for NADH detection. The NADH samples with concentrations of 0.1-1 nM were used to validate the linear relationship, and it was found that the logarithmic deviations were less than 3%, which showed more sensitive and stable results than the NADH detection by recombinant E. coli including the exogenously expressed luciferase and intrinsic Fre. Investigation of P. leiognathi YL LuxG would provide a basic understanding of its evolution, and structural and functional properties, which might contribute to the development of a NADH detection kit in the future.


Assuntos
Proteínas de Bactérias/metabolismo , Medições Luminescentes , NAD/análise , Oxirredutases/metabolismo , Photobacterium/enzimologia , Sequência de Aminoácidos , Proteínas de Bactérias/classificação , Proteínas de Bactérias/genética , Clonagem Molecular , Escherichia coli/metabolismo , Evolução Molecular , Oxirredutases/classificação , Oxirredutases/genética , Filogenia , Estrutura Secundária de Proteína , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Alinhamento de Sequência
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