Antibodies, Viral ; blood ; Betacoronavirus ; immunology ; Coronavirus Infections ; diagnosis ; Gold Colloid ; chemistry ; Humans ; Immunoassay ; methods ; Immunoglobulin G ; blood ; Immunoglobulin M ; blood ; Pandemics ; Pneumonia, Viral ; diagnosis ; Reagent Kits, Diagnostic

Glycosylation of the Fc region of IgG has a profound impact on the safety and clinical efficacy of therapeutic antibodies. While the biantennary complex-type oligosaccharide attached to Asn297 of the Fc is essential for antibody effector functions, fucose and outer-arm sugars attached to the core heptasaccharide that generate structural heterogeneity (glycoforms) exhibit unique biological activities. Hence, efficient and quantitative glycan analysis techniques have been increasingly important for the development and quality control of therapeutic antibodies, and glycan profiles of the Fc are recognized as critical quality attributes. In the past decade our understanding of the influence of glycosylation on the structure/function of IgG-Fc has grown rapidly through X-ray crystallographic and nuclear magnetic resonance studies, which provides possibilities for the design of novel antibody therapeutics. Furthermore, the chemoenzymatic glycoengineering approach using endoglycosidase-based glycosynthases may facilitate the development of homogeneous IgG glycoforms with desirable functionality as next-generation therapeutic antibodies. Thus, the Fc glycans are fertile ground for the improvement of the safety, functionality, and efficacy of therapeutic IgG antibodies in the era of precision medicine.
Animals ; Antibodies, Monoclonal ; adverse effects ; pharmacokinetics ; therapeutic use ; Glycosylation ; Humans ; Immunoglobulin G ; chemistry ; metabolism ; Protein Engineering ; methods ; Receptors, Fc ; chemistry ; metabolism ; Treatment Outcome

Therapeutic monoclonal antibodies become the major product class within the biopharmaceutical market. Protein A as the first capture step is still dominant in current platforms for purification of monoclonal antibodies. In this study, we developed a new antibody harvest process that incorporates acidic treatment of cell harvest, demonstrating high process yield, improved clearance of host cell associated contaminants, like non-histone host cell protein, histone, DNA and heteroaggregates. Host protein contamination was reduced about 10-fold compared to protein A loaded with harvest clarified by centrifugation and microfiltration. Turbidity increase of eluted IgG upon pH neutralization was nearly eliminated. Residual levels of impurities in the protein A eluate were achieved that potentially meet requirements of drug substance and thus alleviate the burden for further impurities removal in subsequent chromatography steps. The mechanism of host cell associated contaminants removal during acidic treatment was also explored. After a polishing step by Capto adhere, host cell protein was reduced to less than 5 ppm, DNA less than 1 ppb, histone to undetectable level, heteroaggregates less than 0.01% with total IgG recovery around 87%. This efficient process can be easily integrated into current IgG purification platforms, and may overcome downstream processing challenges.
Antibodies, Monoclonal ; isolation & purification ; Biotechnology ; Chromatography, Affinity ; DNA ; Histones ; Hydrogen-Ion Concentration ; Immunoglobulin G ; isolation & purification ; Staphylococcal Protein A ; chemistry

Many specific therapeutic antibody drugs have been developed for different indications. In drug development, it has been found that the antibody isotype framework can not only affect the physical and chemical properties of therapeutic antibodies, but also influence the activity and therapeutic effect. As a result, IgG isotype selection should be considered carefully in antibody drug development strategies. Because of the unique biological characteristics, IgG4 isotype has been used in some therapeutic antibodies for which effector functions are not desired. In order to provide new ideas for the development of antibody drugs, the research and application progress of IgG4 isotype in therapeutic antibody drug development has been reviewed.
Drug Design ; Humans ; Immunoglobulin G ; chemistry ; pharmacology

INTRODUCTIONHerpes simplex virus type 2 (HSV-2) is the most common cause of genital herpes. Glycoprotein G (gG) is a prototype antigen for type-specific serodiagnosis distinguishing between HSV type 1 (HSV-1) and HSV-2 infections. As immunological diagnosis kits for accurate differentiation between HSV-1 and HSV-2 antibodies can be expensive, there is a need to develop a convenient, sensitive, specific and cost-effective serodiagnostic kit.

METHODSWe successfully expressed a fragment of gG comprising residues 321-580 of HSV-2 with histidine tag (gG(321-580His)) in a Bac-to-Bac baculovirus expression system, which had an antigenicity similar to its native counterpart. An indirect enzyme-linked immunosorbent assay (ELISA) was developed using gG(321-580His) as the diagnostic antigen and evaluated by comparison with a commercial HerpeSelect 2 ELISA immunoglobulin G kit as reference.

RESULTSIn testing 318 field serum samples, the diagnostic relative sensitivity and specificity of the developed gG(321-580His)-ELISA test in qualitative comparison with the commercial kit were 93.81% and 96.74%, respectively, and the accuracy was 94.65%.

CONCLUSIONThe study indicates that gG(321-580His) has a high diagnostic potential for HSV-2 virus serodiagnosis in humans.

Adult ; Antibodies, Viral ; blood ; Enzyme-Linked Immunosorbent Assay ; Female ; Herpes Genitalis ; diagnosis ; virology ; Herpes Simplex ; diagnosis ; virology ; Herpesvirus 1, Human ; isolation & purification ; Herpesvirus 2, Human ; isolation & purification ; Humans ; Immunoglobulin G ; chemistry ; Male ; Polymerase Chain Reaction ; Reagent Kits, Diagnostic ; Reference Values ; Reproducibility of Results ; Sensitivity and Specificity ; Serologic Tests ; methods

OBJECTIVETo investigate the effect of Rhizoma Atractylodis extract (ERA) in protecting gastric mucosa and modulating gastrointestinal immune function of a rat model of spleen deficiency syndrome and elucidate the mechanism by which ERA improves spleen deficiency syndrome.

METHODSMale rats were fed with Xiaochengqi decoction and subjected to irregular feeding to induce spleen deficiency syndrome. The established models were randomized into model group, high-, moderate- and low-dose ERA groups, and domperidone group. After corresponding treatment for 30 days, the content of IgA in the intestinal lavage fluid, serum IgG, and the indices of the spleen and thymus were determined. The pathological changes in the gastric mucosa was observed with HE staining, gastric mucosal blood flow was evaluated with laser Doppler rheometry, and the expression of TFF1 in the gastric mucosa and TLR4 expression in the colon tissue were detected with immunohistochemistry.

RESULTSThe rat models of spleen deficiency syndrome showed obvious abnormalities in gastric mucosal morphology, blood flow and immunological indexes. Compared with the model rats, the rats receiving ERA treatment as different doses all showed significant improvements in gastric mucosal morphology, blood flow volume, gastric mucosa trefoil factor 1 (TFF1) expression, intestinal lavage fluid IgA content, serum IgG content, indices of the spleen and thymus, and TLR4 expression in the colon TLR4 (P<0.05 or P<0.01).

CONCLUSIONERA can inhibit gastric mucosal damage, protect and repair the damaged mucosal tissues, and improve the immune function of in rats with spleen deficiency.

Animals ; Atractylodes ; chemistry ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; Gastric Mucosa ; drug effects ; pathology ; Immunoglobulin A ; metabolism ; Immunoglobulin G ; blood ; Immunohistochemistry ; Male ; Peptides ; metabolism ; Rats ; Rhizome ; chemistry ; Spleen ; physiopathology ; Trefoil Factor-2

OBJECTIVETo study the prevalence of IgG4-positive plasma cells in Rosai-Dorfman disease and to assess the association between Rosai-Dorfman disease and IgG4-related sclerosing disease (IgG4-SD).

METHODSThe clinicopathologic features of 12 tissue samples of Rosai-Dorfman disease (11 extranodal and one nodal) from nine patients were reviewed. The degree of fibrosis and occlusive phlebitis was studied by HE staining. The expression of IgG4 and IgG in plasma cells were studied by immunohistochemistry (EnVision) and quantitatively analyzed by medical image analysis system.

RESULTSNine tissue samples showed different degree of fibrosis (four tissue samples were mild, one tissue sample was moderate and four tissue samples were severe) and two tissue samples showed occlusive phlebitis in the lesional tissue. Immunohistochemical study showed marked infiltration by IgG4-positive plasma cells (> 50 per high-power field) in four tissue samples, moderate infiltration (30 to 50 per high-power field) in two tissue samples, mild (10 to 29 per high-power field) in three cases and negative infiltration (< 10 per high-power field) in three tissue samples (P < 0.01). Three tissue samples fulfilled the diagnostic criteria of IgG4-SD (> 50 IgG4-positive plasma cells per high-power field and IgG4-to-IgG ratio > 40%), including one tissue sample each of Rosai-Dorfman disease in the left facial skin, above the left eye socket, and in the right parotid.

CONCLUSIONSSome cases of Rosai-Dorfman disease fulfill the diagnostic criteria and show the histologic features of IgG4-SD. They may represent members of the IgG4-SD spectrum. The detection of IgG4-positive plasma cells in the lesional tissues of Rosai-Dorfman disease may have clinical pathological significance.

Fibrosis ; Histiocytosis, Sinus ; diagnosis ; immunology ; Humans ; Immunoglobulin G ; chemistry ; Immunohistochemistry ; Phlebitis ; pathology ; Plasma Cells ; chemistry

BACKGROUND: Without appropriate culture systems for hepatitis E virus (HEV), sufficient natural viral proteins are difficult to generate for use in serological tests. Therefore, it is important to produce large amounts of HEV recombinant proteins in an economical way. The present study developed ELISAs using 2 truncated forms of the HEV open reading frame (ORF) 2 protein in order to detect anti-HEV IgG in serum samples. METHODS: Two truncated forms of the ORF2 protein were expressed in Escherichia coli and were purified by Ni2+-chelate-affinity chromatography (Qiagen, Germany). Two ELISAs were developed using these proteins and were compared with DIA.PRO HEV IgG ELISA kit (DIA.PRO. Italy) in 220 serum samples. RESULTS: High yields of the target proteins were obtained through codon optimization. The concentration and purity of the proteins were improved with Amicon filters (EMD Millipore, USA). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting analysis of the resultant proteins showed a protein band of approximately 60 kDa corresponding to ORF2.1 (amino acids 112-660) and a protein band of approximately 55 kDa corresponding to ORF2.2 (amino acids 112-607). Positive agreement, negative agreement, and concordance of the 2 in-house ELISAs compared with DIA.PRO HEV IgG ELISA kit were 87%, 99.5%, and 98.1%, respectively (kappa=0.899, P=0.625). CONCLUSIONS: The newly developed ELISAs are useful for detecting anti-HEV IgG in serum samples and are highly concordant with DIA.PRO HEV IgG ELISA kit.
Amino Acid Sequence ; Antibodies/*blood ; *Enzyme-Linked Immunosorbent Assay ; Escherichia coli/metabolism ; Hepatitis E virus/*metabolism ; Humans ; Immunoglobulin G/*blood ; Molecular Sequence Data ; Recombinant Proteins/biosynthesis/immunology/isolation & purification ; Sequence Alignment ; Viral Proteins/chemistry/*immunology/metabolism

Recombinant antigenic proteins of Toxoplasma gondii are alternative source of antigens which are easily obtainable for serodiagnosis of toxoplasmosis. In this study, highly antigenic secretory organellar proteins, dense granular GRA2 and GRA3, rhoptrial ROP2, and micronemal MIC2, were analyzed by bioinformatics approach to express as water-soluble forms of antigenic domains. The transmembrane region and disorder tendency of 4 secretory proteins were predicted to clone the genes into pGEX-4T-1 vector. Recombinant plasmids were transformed into BL21 (DE3) pLysS E. coli, and GST fusion proteins were expressed with IPTG. As a result, GST fusion proteins with GRA225-105, GRA339-138, ROP2324-561, and MIC21-284 domains had respectively higher value of IgG avidity. The rGST-GRA225-105 and rGST-GRA339-138 were soluble, while rGST-ROP2324-561 and rGST-MIC21-284 were not. GRA231-71, intrinsically unstructured domain (IUD) of GRA2, was used as a linker to enhance the solubility. The rGST-GRA231-71-ROP2324-561, a chimeric protein, appeared to be soluble. Moreover, rGST-GRA231-71-MIC21-284 was also soluble and had higher IgG avidity comparing to rGST-MIC21-284. These 4 highly expressed and water-soluble recombinant antigenic proteins may be promising candidates to improve the serodiagnosis of toxoplasmosis in addition to the major surface antigen of SAG1.
Animals ; Antibodies, Protozoan/immunology ; Antibody Affinity ; Antigens, Protozoan/chemistry/*diagnostic use/genetics/immunology ; *Gene Expression ; Immunoglobulin G/blood/immunology ; Mice, Inbred BALB C ; Recombinant Proteins/chemistry/*diagnostic use/genetics/immunology ; Serologic Tests/methods ; Solubility ; Toxoplasma/genetics/immunology/*metabolism ; Toxoplasmosis/diagnosis

OBJECTIVETo evaluate the efficacy and safety of etanercept plus Tripterygium wilfordii polyglycoside (TWP) in elderly patients with active rheumatoid arthritis (RA).

METHODSTotally 46 elderly patients with active RA were randomly assigned to the treatment group (22 cases) and the control group (24 cases). All patients received subcutaneous injection of etanercept, 25 mg each time, twice per week. The dosage was reduced to once per week 3 months later. Patients in the treatment group took TWP Tablet (10 mg each time, three times per day), while those in the control group took methotrexate (MTX), 10 mg each time, once per week. The whole course lasted for 24 weeks. Patients' rest pain, tender joint number, swollen joint number, health assessment questionnaire (HAQ), patients' global assessment, physicians' global assessment, erythrocyte sediment rate (ESR), C reactive protein (CRP), rheumatic factor were assessed at week 0, 4, 8, 12, and 24. The curative effect was statistically evaluated by the United States Institute of Rheumatology ACR20, ACR50, and ACR70 improvement criteria. Meanwhile, any adverse event was recorded and evaluated.

RESULTSTotally 41 completed the trial, and 5 dropped off (3 in the treatment group and 2 in the control group). Compared with the control group, there was no statistical difference in ACR20, ACR50, or ACR70 in the treatment group (P > 0.05). Compared with before treatment in the same group, there was some improvement in tender joint number, swollen joint number, visual analogue scale (VAS) for patients' global assessment, VAS for physicians' global assessment, ESR, CRP, and HAQ between the two groups, showing statistical difference (P < 0.05). Compared with the control group in the same phase, there was no statistical difference in the treatment group (P > 0.05). There was no statistical difference in the occurrence of adverse events between the two groups.

CONCLUSIONSEtanercept plus TWP could achieve equivalent therapeutic effect to that of Etanercept plus MTX. The two regimens could improve clinical signs, symptoms, and QOL related to RA. They were well tolerated in the treatment of elderly patients with active RA.

Aged ; Antirheumatic Agents ; therapeutic use ; Arthritis, Rheumatoid ; drug therapy ; Drug Therapy, Combination ; Etanercept ; Female ; Glycosides ; therapeutic use ; Humans ; Immunoglobulin G ; therapeutic use ; Male ; Middle Aged ; Receptors, Tumor Necrosis Factor ; therapeutic use ; Treatment Outcome ; Tripterygium ; chemistry