Research on IgG4-related disease (IgG4-RD), an autoimmune condition recognized to be a unique disease entity only two decades ago, has processed from describing patients' symptoms and signs to summarizing its critical pathological features, and further to investigating key pathogenic mechanisms. Challenges in gaining a better understanding of the disease, however, stem from its relative rarity-potentially attributed to underrecognition-and the absence of ideal experimental animal models. Recently, with the development of various high-throughput techniques, "omics" studies at different levels (particularly the single-cell omics) have shown promise in providing detailed molecular features of IgG4-RD. While, the application of omics approaches in IgG4-RD is still at an early stage. In this paper, we review the current progress of omics research in IgG4-RD and discuss the value of machine learning methods in analyzing the data with high dimensionality.
Humans ; Immunoglobulin G4-Related Disease/metabolism* ; Immunoglobulin G/metabolism* ; Machine Learning ; Animals ; Proteomics/methods*

OBJECTIVES: This study aimed to explore the therapeutic effect and mechanism of ginsenoside Rb3 on experimental periodontitis and bone resorption in rats. METHODS: Male SD rats were randomly divided into a control group, a ligation group, an Rb3 group, and a doxycycline (Dox) group for in vivo experiments. A periodontitis model was established by ligating the maxillary second molar, and samples were collected after 3 weeks of drug treatment. Micro-CT assessment of alveolar bone resorption was performed, and hematoxylin-eosin (HE) staining was used to observe pathological changes in periodontal and visceral tissues. Tartrate resistant acid phosphatase (TRAP) staining was applied to detect the formation of osteoclasts in periodontal tissues, and enzyme-linked immunosorbent assay (ELISA) was adopted to detect the serum levels of interleukin (IL)-6, IL-8, immunoglobulin (Ig)M, and IgG. Quantitative polymerase chain reaction (qPCR) was employed to detect the expression of factors related to gingival inflammation and osteoclast formation. Immunofluorescence staining was used to detect phospho-extracellular signal-regulated kinase (p-ERK) expression. In vitro experiments were conducted by pretreating RAW264.7 cells with drugs and adding lipopolysaccharides (LPS) stimulation from Porphyromonas gingivalis (P. gingivalis). IL-1β and IL-6 mRNA expression was detected by qPCR, and Western blot was used to detect the effect of Rb3 on the mitogen-activated protein kinases (MAPKs) signaling pathway. RESULTS: Compared with the control group, the ligation group showed significant periodontitis and bone resorption. Compared with the ligation group, the Rb3 group showed a decrease in alveolar bone resorption and osteoclast formation; p-ERK/ERK ratio, IL-1β, IL-6, and nuclear factor of activated T cells (NFATc1) mRNA levels and downstream gene expression in periodontal tissues; serum IL-6, IL-8, IgG, and IgM levels. Rb3 reduced IL-8 and IL-1β mRNA expression levels and p-ERK/ERK and p-p38 MAPK/p38 MAPK ratios in RAW264.7 cells induced by P. gingivalis LPS stimulation. CONCLUSIONS Rb3 inhibits inflammation and bone resorption in experimental periodontitis in rats. Compared with Dox, Rb3 has better effects in inhibiting pro-inflammatory factors and osteoclast gene expression and may exert anti-inflammatory effects by activating the MAPK signaling pathway.
Animals ; Ginsenosides/therapeutic use* ; Rats, Sprague-Dawley ; Male ; Periodontitis/pathology* ; Rats ; Osteoclasts/drug effects* ; Interleukin-1beta/metabolism* ; Interleukin-6/blood* ; Mice ; Alveolar Bone Loss ; Interleukin-8/blood* ; Immunoglobulin G/blood* ; RAW 264.7 Cells ; Transcription Factors

In this study, we constructed a series of recombinant Fc variants of immunoglobulin G4 (IgG4), screened the fragment crystallizable (Fc) variants with significantly prolonged serum half-lives, and analyzed the relationship between mutation site and half-life, aiming to provide a theoretical basis for the development of IgG4 antibodies and Fc fusion protein-based drugs. Nine gene sites were selected for mutation, and different mutation sites were combined. The variant expression plasmids pET24b-Fc were constructed by molecular cloning and point mutation. The plasmids were transformed into Escherichia coli BL21(DE3) for the expression of different recombinant proteins of Fc. Fc2 and Fc3 variants had slightly lower recombinant protein yields, and the expression of other variants was not affected. The toxicity of different Fc variants was determined by cell counting kit-8 (CCK-8) and calcein acetoxymethyl ester/ propidium iodide (calcein AM/PI) in vitro and enzyme-linked immuno sorbent assay (ELISA) in vivo. The results showed that the recombinant Fc variants had good biocompatibility and safety. Finally, the Fc variants were labeled with fluorescent markers, and the effects of different mutations on their serum half-lives were investigated by in vivo experiments. The Fc5 variant with prolonged serum half-life was successfully screened out, which provided a theoretical and practical basis for the optimal design of IgG4 subtype antibody and Fc fusion protein drugs.
Immunoglobulin G/blood* ; Immunoglobulin Fc Fragments/biosynthesis* ; Half-Life ; Animals ; Escherichia coli/metabolism* ; Humans ; Recombinant Fusion Proteins/biosynthesis* ; Recombinant Proteins/biosynthesis* ; Mice

This study aimed to investigate the mechanism by which Shegan Mahuang Decoction(SGMH) and its bitter Chinese herbs(BCHs) regulated the lung-gut axis through the bitter taste receptor 14(TAS2R14)/secretory immunoglobulin A(SIgA)/thymic stromal lymphopoietin(TSLP) to intervene in the epithelial cell barrier of cold asthma rats. Fifty SD rats were randomly divided into the following five groups: normal group, model group, dexamethasone group, SGMH group, and BCHs group. A 10% ovalbumin(OVA) solution was used to sensitize the rats via subcutaneous injection on both sides of the abdomen and groin, combined with 2% OVA atomization and cold(2-4 ℃) stimulation to induce a cold asthma model in rats. The SGMH, BCHs, and dexamethasone groups were given corresponding treatments by gavage and nebulization, while the normal and model groups received normal saline by gavage and nebulization. After the final stimulation, pathological changes in the lung and intestine tissues were observed using hematoxylin-eosin(HE) and periodic acid-Schiff(PAS) staining. Lung function was assessed by measuring the ratio of forced expiratory volume in the first second to forced vital capacity(FEV1/FVC), the ratio of the average flow rate at 25%-75% of forced vital capacity to foned vital capacity(FEV25%-75%/FVC), the peak expiratory flow(PEF), and pulmonary resistance(RL). The levels of IL-4, IL-5, IL-13, and TNF-α in serum, and sIgA in serum, intestinal, and bronchial mucosa were detected by enzyme-linked immunosorbent assay(ELISA). The expression of TAS2R14 protein in lung tissue was detected by Western blot(WB). The content of short-chain fatty acids(SCFAs) in rat feces was determined by gas chromatography-mass spectrometry(GC-MS). The effect of TAS2R14/TSLP on lipopolysaccharide(LPS)-induced inflammation in epithelial cells in the BCHs group was observed, and the expression of TAS2R14 and TSLP in cells was detected by WB. Compared with the normal group, the model group showed reduced water intake, diet, and body weight, increased infiltration of inflammatory cells in the lung and intestinal tissues, goblet cell hyperplasia, significantly decreased FEV1/FVC, FEV25%-75%/FVC, and PEF, and significantly increased RL. Moreover, serum levels of IL-4, IL-5, IL-13, and TNF-α were elevated, and sIgA levels in serum, intestine, and bronchial mucosa were significantly decreased. TAS2R14 expression in lung tissues was inhibited, and the content of acetic acid, propionic acid, and butyric acid in feces was significantly reduced. In the LPS group, TSLP expression increased, and TAS2R14 expression decreased. Compared with the model group, the general condition of rats in the SGMH and BCHs groups improved, with reduced infiltration of inflammatory cells and goblet cell hyperplasia in the lung and intestinal tissues. FEV1/FVC, FEV25%-75%/FVC, and PEF significantly increased, and RL significantly decreased. Serum levels of IL-4, IL-5, IL-13, and TNF-α decreased, while sIgA levels in serum, intestine, and bronchial mucosa significantly increased, and TAS2R14 expression was activated in lung and intestinal tissues. The content of acetic acid, propionic acid, and butyric acid in feces significantly increased. Compared with the model group, the BCHs group and the agonist group showed inhibited TSLP expression and increased TAS2R14 expression. The results showed that both SGMH and BCHs could reduce lung and intestinal inflammatory reactions, improve lung function, and regulate the content of intestinal SCFAs in asthmatic rats. There was no significant difference in TAS2R14 protein expression between the SGMH and BCHs groups, indicating that the clinical efficacy of BCHs may be related to the activation of the bitter receptor TAS2R14 and the regulation of immune inflammatory mediators in lung and intestinal epithelial cells.
Animals ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; Rats, Sprague-Dawley ; Lung/metabolism* ; Asthma/metabolism* ; Cytokines/immunology* ; Male ; Receptors, G-Protein-Coupled/immunology* ; Epithelial Cells/metabolism* ; Thymic Stromal Lymphopoietin ; Immunoglobulin A, Secretory/genetics* ; Humans ; Cold Temperature

OBJECTIVE: This study prospectively investigates the association between immunoglobulin G (IgG) N-glycan traits and ischemic stroke (IS) risk. METHODS: A nested case-control study was conducted in the China suboptimal health cohort study, which recruited 4,313 individuals in 2013-2014. Cases were identified as patients diagnosed with IS, and controls were 1:1 matched by age and sex with cases. IgG N-glycans in baseline plasma samples were analyzed. RESULTS: A total of 99 IS cases and 99 controls were included, and 24 directly measured glycan peaks (GPs) were separated from IgG N-glycans. In directly measured GPs, GP4, GP9, GP21, GP22, GP23, and GP24 were associated with the risk of IS in men after adjusting for age, waist and hip circumference, obesity, diabetes, hypertension, and dyslipidemia. Derived glycan traits representing decreased galactosylation and sialylation were associated with IS in men (FBG2S2/(FBG2 + FBG2S1 + FBG2S2): odds ratio ( OR) = 0.92, 95% confidence interval ( CI): 0.87-0.97; G1 ⁿ: OR = 0.74, 95% CI: 0.63-0.87; G0 ⁿ: OR = 1.12, 95% CI: 1.03-1.22). However, these associations were not found among women. CONCLUSION This study validated that altered IgG N-glycan traits were associated with incident IS in men, suggesting that sex discrepancies might exist in these associations.
Male ; Humans ; Female ; Immunoglobulin G/metabolism* ; Ischemic Stroke ; Case-Control Studies ; Cohort Studies ; Glycosylation ; Polysaccharides

Immunoglobulin (IgG) glycosylation affects the effector functions of IgG in a myriad of biological processes and has been closely associated with numerous autoimmune diseases, including systemic lupus erythematosus (SLE), thus underlining the pathogenic role of glycosylation aberration in autoimmunity. This study aims to explore the relationship between IgG sialylation patterns and lupus pregnancy. Relative to that in serum samples from the control cohort, IgG sialylation level was aberrantly downregulated in serum samples from the SLE cohort at four stages (from preconception to the third trimester of pregnancy) and was significantly associated with lupus activity and fetal loss during lupus pregnancy. The type I interferon signature of pregnant patients with SLE was negatively correlated with the level of IgG sialylation. The lack of sialylation dampened the ability of IgG to suppress the functions of plasmacytoid dendritic cells (pDCs). RNA-seq analysis further revealed that the expression of genes associated with the spleen tyrosine kinase (SYK) signaling pathway significantly differed between IgG- and deSia-IgG-treated pDCs. This finding was confirmed by the attenuation of the ability to phosphorylate SYK and BLNK in deSia-IgG. Finally, the coculture of pDCs isolated from pregnant patients with SLE with IgG/deSia-IgG demonstrated the sialylation-dependent anti-inflammatory function of IgG. Our findings suggested that IgG influences lupus activity through regulating pDCs function via the modulation of the SYK pathway in a sialic acid-dependent manner.
Humans ; Pregnancy ; Female ; Lupus Erythematosus, Systemic/pathology* ; Signal Transduction ; N-Acetylneuraminic Acid/metabolism* ; Immunoglobulin G ; Dendritic Cells/pathology*

Objective: To investigate the value of plasma cells for diagnosing lymph node diseases. Methods: Common lymphadenopathy (except plasma cell neoplasms) diagnosed from September 2012 to August 2022 were selected from the pathological records of Changhai Hospital, Shanghai, China. Morphological and immunohistochemical features were analyzed to examine the infiltration pattern, clonality, and IgG and IgG4 expression of plasma cells in these lymphadenopathies, and to summarize the differential diagnoses of plasma cell infiltration in common lymphadenopathies. Results: A total of 236 cases of lymphadenopathies with various degrees of plasma cell infiltration were included in the study. There were 58 cases of Castleman's disease, 55 cases of IgG4-related lymphadenopathy, 14 cases of syphilitic lymphadenitis, 2 cases of rheumatoid lymphadenitis, 18 cases of Rosai-Dorfman disease, 23 cases of Kimura's disease, 13 cases of dermal lymphadenitis and 53 cases of angioimmunoblastic T-cell lymphoma (AITL). The main features of these lymphadenopathies were lymph node enlargement with various degrees of plasm cell infiltration. A panel of immunohistochemical antibodies were used to examine the distribution of plasma cells and the expression of IgG and IgG4. The presence of lymph node architecture could help determine benign and malignant lesions. The preliminary classification of these lymphadenopathies was based on the infiltration features of plasma cells. The evaluation of IgG and IgG4 as a routine means could exclude the lymph nodes involvement of IgG4-related dieases (IgG4-RD), and whether it was accompanied by autoimmune diseases or multiple-organ diseases, which were of critical evidence for the differential diagnosis. For common lesions of lymphadenopathies, such as Castleman's disease, Kimura's disease, Rosai-Dorfman's disease and dermal lymphadenitis, the expression ratio of IgG4/IgG (>40%) as detected using immunhistochemistry and serum IgG4 levels should be considered as a standard for the possibility of IgG4-RD. The differential diagnosis of multicentric Castleman's diseases and IgG4-RD should be also considered. Conclusions: Infiltration of plasma cells and IgG4-positive plasma cells may be detected in some types of lymphadenopathies and lymphomas in clinicopathological daily practice, but not all of them are related to IgG4-RD. It should be emphasized that the characteristics of plasma cell infiltration and the ratio of IgG4/IgG (>40%) should be considered for further differential diagnosis and avoiding misclassification of lymphadenopathies.
Humans ; Castleman Disease/pathology* ; Plasma Cells/pathology* ; Immunoglobulin G4-Related Disease ; China ; Lymphadenopathy/pathology* ; Inflammation/pathology* ; Lymph Nodes/pathology* ; Diagnosis, Differential ; Lymphadenitis/pathology* ; Immunoglobulin G/metabolism*

Immunoglobulin G4-related sialadenitis (IgG4-RS) is an immune-mediated fibro-inflammatory disease and the pathogenesis is still not fully understood. The aim of this study was to explore the role and mechanism of interleukin-13 (IL-13) in the cellular senescence during the progress of IgG4-RS. We found that the expression of IL-13 and IL-13 receptor α1 (IL-13Rα1) as well as the number of senescent cells were significantly higher in the submandibular glands (SMGs) of IgG4-RS patients. IL-13 directly induced senescence as shown by the elevated activity of senescence-associated β-galactosidase (SA-β-gal), the decreased cell proliferation, and the upregulation of senescence markers (p53 and p16) and senescence-associated secretory phenotype (SASP) factors (IL-1β and IL-6) in SMG-C6 cells. Mechanistically, IL-13 increased the level of phosphorylated signal transducer and activator of transcription 6 (p-STAT6) and mitochondrial-reactive oxygen species (mtROS), while decreased the mitochondrial membrane potential, ATP level, and the expression and activity of superoxide dismutase 2 (SOD2). Notably, the IL-13-induced cellular senescence and mitochondrial dysfunction could be inhibited by pretreatment with either STAT6 inhibitor AS1517499 or mitochondria-targeted ROS scavenger MitoTEMPO. Moreover, IL-13 increased the interaction between p-STAT6 and cAMP-response element binding protein (CREB)-binding protein (CBP) and decreased the transcriptional activity of CREB on SOD2. Taken together, our findings revealed a critical role of IL-13 in the induction of salivary gland epithelial cell senescence through the elevated mitochondrial oxidative stress in a STAT6-CREB-SOD2-dependent pathway in IgG4-RS.
Cellular Senescence/genetics* ; Humans ; Immunoglobulin G/metabolism* ; Interleukin-13/pharmacology* ; Mitochondria/metabolism* ; Sialadenitis/metabolism*

Objective: To express DNA-binding protein (DBP) of human adenovirus (HAdV) type 7 using the prokaryotic expression system, and product anti-HAdV-7 DBP rabbit polyclonal antibody. Methods: The HAdV-7 DBP gene was synthesized and cloned into prokaryotic expressing vector pET30a, and the recombinant plasmid was transformed into E. coli BL21 (DE3) competent cell. The recombinant protein DBP was expressed by induced Isopropyl-beta-D-thiogalactopyranoside (IPTG) and purified with Ni-NTA affinity column. The titer of anti-DBP polyclonal antibody produced in immunized rabbit was measured by indirect ELISA, and the specificity of the antibody was identified by Western blotting and indirect immunofluorescence assay (IFA). In addition, purified rDBP was used as coating antigen for indirect ELISA assay to detect specific IgM and IgG antibodies against DBP in the serum of children infected with HAdV. Results: The HAdV-7 DBP plasmid was constructed successfully. The purified recombinant DBP was more than 95% after purification. The titer of polyclonal antibody was 1∶1 024 000. The polyclonal antibody showed high specificity in vitro using Western blotting and IFA. The positive rate of specific anti-DBP IgM and IgG antibody in acute-phase serum samples collected from children infected with HAdV were 50.0% (19/38) and 63.2% (24/38), respectively, using indirect ELISA. Conclusion: In summary, the HAdV-7 rDBP is expressed using prokaryotic expression system, and the recombinant HAdV-7 DBP protein and the anti-DBP rabbit polyclonal antibody with high titer are prepared.
Adenoviruses, Human/genetics* ; Animals ; Antibody Specificity ; Blotting, Western ; DNA-Binding Proteins/metabolism* ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli/genetics* ; Immunoglobulin G ; Rabbits

Adult ; Aged ; Antibodies, Viral/metabolism* ; China ; Female ; Humans ; Immunoglobulin G/metabolism* ; Male ; Measles/metabolism* ; Measles virus/physiology* ; Medical Staff ; Middle Aged ; Saliva/virology* ; Young Adult