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

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

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

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

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

BACKGROUND/AIMS: Ulcerative colitis (UC) is sometimes associated with autoimmune pancreatitis (AIP). Infiltration of immunoglobulin G4 (IgG4)-positive plasma cells is sometimes detected in the colonic mucosa of AIP or UC patients. This study aimed to clarify the relation between UC and IgG4. METHODS: Associations with UC were reviewed in 85 AIP patients. IgG4 immunostaining was performed on biopsy specimens from the colonic mucosa of 14 AIP and 32 UC patients. RESULTS: UC was confirmed in two cases (type 1 AIP, n=1; suspected type 2 AIP, n=1). Abundant infiltration of IgG4-positive plasma cells in the colonic mucosa was detected in the case of suspected type 2 AIP with UC and two cases of type 1 AIP without colitis. Abundant infiltration of IgG4-positive plasma cells was detected in 10 UC cases (IgG4-present, 31%). Although 72% of IgG4-absent UC patients showed mild disease activity, 70% of IgG4-present patients showed moderate to severe disease activity (p<0.05). CONCLUSIONS: UC is sometimes associated with AIP, but it seems that UC is not a manifestation of IgG4-related disease. Infiltration of IgG4-positive plasma cells is sometimes detectable in the colonic mucosa of UC patients and is associated with disease activity.
Adult ; Aged ; Colitis, Ulcerative/*blood/complications ; Colon/*chemistry ; Female ; Humans ; Immunoglobulin G/*analysis ; Intestinal Mucosa/*chemistry ; Male ; Middle Aged ; Pancreatitis/*blood/complications ; Retrospective Studies

Several studies have reported that the citrus red mites Panonychus citri were an important allergen of citrus-cultivating farmers in Jeju Island. The aim of the present study was to purify and assess properties of a cysteine protease from the mites acting as a potentially pathogenic factor to citrus-cultivating farmers. A cysteine protease was purified using column chromatography of Mono Q anion exchanger and Superdex 200 HR gel filtration. It was estimated to be 46 kDa by gel filtration column chromatography and consisted of 2 polypeptides, at least. Cysteine protease inhibitors, such as trans poxy-succinyl-L-leucyl-amido (4-guanidino) butane (E-64) and iodoacetic acid (IAA) totally inhibited the enzyme activities, whereas serine or metalloprotease inhibitors did not affect the activities. In addition, the purified enzyme degraded human IgG, collagen, and fibronectin, but not egg albumin. From these results, the cysteine protease of the mites might be involved in the pathogenesis such as tissue destruction and penetration instead of nutrient digestion.
Animals ; Chromatography, Gel ; Chromatography, Ion Exchange ; Collagen/metabolism ; Cysteine Proteases/chemistry/*isolation & purification ; Cysteine Proteinase Inhibitors/metabolism ; Fibronectins/metabolism ; Humans ; Immunoglobulin G/metabolism ; Molecular Weight ; Protein Subunits/chemistry/isolation & purification ; Proteolysis ; Substrate Specificity ; Tetranychidae/*enzymology

OBJECTIVETo study the effects of the Rich Selenium-Banqiao-Codonopsis Pilosula (BCPA) injecta on the aged rats' immune functions and its underlying mechanism.

METHODSTotally 60 rats, composed of 2, 12 and 22 month age old (half male and half female), were served as a young group, middle-age group and aged group respectively. Each group rats were randomly divided into the control and the BCPA subgroup (n = 10). The BCPA group was injected with BCPA at 7.2 g/kg intraperitoneally every day and the control group was injected the same volume of normal saline. All rats were conventionally fed for 45 days. An immune injection was performed after 15 days of BCPA injection. On the 22nd day, late-onset immune response would be induced. The caudal vein blood was collected and the antigen specific IgG, IgG1 and IgG2a antibody was detected on the 15th, 30th and 45th day. On the 45th day, the major T cell subgroups of splenic cells were analyzed and splenic cells were proliferated.

RESULTSNo significant difference in the delayed-type hypersensivity (DTH) reaction was found between the control and the BCPA subgroups in the young and middle-aged rats while the aged BCPA subgroup had a stronger DTH reaction. There was no significant difference in the blood content of specific IgG, IgG1 and IgG2a antibody between the young and middle-age BCPA group while the aged BCPA group rats had an obvious enhancing reaction to the three antibodies mentioned above (P < 0.05). There was no obvious difference in the number of the CD3+ lymphocytes and the CD4+ T helper lymphocytes between the control and the BCPA subgroup in the young aged rats while a significant increase was spotted between the middle-aged and the aged group (P < 0.05). The splenic cells from young BCPA group rats had a strong proliferation response (P < 0.05).

CONCLUSIONBCPA can enhance DTH reaction, potentiate the production of specific IgG, IgG1 and IgG2a antibody to resist KLH, improve the reaction to antigen, increase the amount of CD4+ cell, promote the immune response and had an important role in anti-immunosenescence and antioxidant capacity improvement in the aged rats.

Aging ; Animals ; CD4-Positive T-Lymphocytes ; immunology ; Codonopsis ; chemistry ; Drugs, Chinese Herbal ; pharmacology ; Female ; Immune System ; drug effects ; Immunoglobulin G ; blood ; Male ; Rats ; Selenium ; pharmacology ; Spleen ; immunology