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

The humoral immune response of B cells is the key to the protection of specific immunity, and immune aging reshapes its production and function. The decreased B cell immune function is an indicator of immune senescence. The impaired humoral immune function mediated by antibody secreted by B cells leads to a decline in the response of elderly individuals to the vaccine. These people are therefore more susceptible to infection and deterioration, and have a higher incidence of tumors and metabolic diseases. Activation-induced cytidine deaminase (AID) is an enzyme that triggers immunoglobulin class conversion recombination (CSR) and somatic high frequency mutation (SHM). It decreases during immune senescence and is considered to be a biomarker of decreased B cell function in aging mice and humans. Understanding the inherent defects of B-cell immune senescence and the regulation mechanism of AID in the aging process can provide new research ideas for the susceptibility, prevention and treatment of diseases in the elderly.
Animals ; Humans ; Mice ; Aging/metabolism* ; B-Lymphocytes/metabolism* ; Cytidine Deaminase/metabolism* ; Somatic Hypermutation, Immunoglobulin

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*

OBJECTIVES: To investigate the change in the distribution of memory B cell subsets in children with frequently relapsing nephrotic syndrome (FRNS) during the course of the disease. METHODS: A total of 35 children with primary nephrotic syndrome (PNS) who attended the Department of Pediatrics of the Affiliated Hospital of Xuzhou Medical University from October 2020 to October 2021 were enrolled as subjects in this prospective study. According to the response to glucocorticoid (GC) therapy and frequency of recurrence, the children were divided into two groups: FRNS (n=20) and non-FRNS (NFRNS; n=15). Fifteen children who underwent physical examination were enrolled as the control group. The change in memory B cells after GC therapy was compared between groups, and its correlation with clinical indicators was analyzed. RESULTS: Before treatment, the FRNS and NFRNS groups had significantly increased percentages of total B cells, total memory B cells, IgD⁺ memory B cells, and IgE⁺ memory B cells compared with the control group, and the FRNS group had significantly greater increases than the NFRNS group (P<0.05); the FRNS group had a significantly lower percentage of class-switched memory B cells than the NFRNS and control groups (P<0.05). After treatment, the FRNS and NFRNS groups had significant reductions in the percentages of total B cells, total memory B cells, IgM⁺IgD⁺ memory B cells, IgM⁺ memory B cells, IgE⁺ memory B cells, IgD⁺ memory B cells, and IgG⁺ memory B cells (P<0.05) and a significant increase in the percentage of class-switched memory B cells (P<0.05). The FRNS group had a significantly higher urinary protein quantification than the NFRNS and control groups (P<0.05) and a significantly lower level of albumin than the control group (P<0.05). In the FRNS group, urinary protein quantification was negatively correlated with the percentage of class-switched memory B cells and was positively correlated with the percentage of IgE⁺ memory B cells (P<0.05). CONCLUSIONS Abnormal distribution of memory B cell subsets may be observed in children with FRNS, and the percentages of IgE⁺ memory B cells and class-switched memory B cells can be used as positive and negative correlation factors for predicting recurrence after GC therapy in these children.
Child ; Humans ; B-Lymphocyte Subsets/metabolism* ; Immunoglobulin E ; Immunoglobulin M ; Nephrotic Syndrome/immunology* ; Prospective Studies ; Glucocorticoids/therapeutic use*

Lectins are proteins responsible for recognizing the signals of sugar molecules in the body. Sialic acid-binding immunoglobulin-like lectins (Siglecs) regulate the innate and adaptive immune responses in the tumor microenvironment by recognizing the glycan structure containing sialic acid and mediating downstream signals through immune receptor tyrosine inhibitory motifs. In recent years, a variety of tumor treatment strategies targeting the sialic acid-Siglecs axis have been introduced, including sialoglycoprotein-mediated drug delivery and antibody mediated inhibition of Siglecs from recognizing tumor surface ligands. In the future, by combining with glycoprotein nanotherapy, antibody therapy and gene therapy, Siglecs can be used to accurately locate tumor targets and release the anti-tumor immunity, so as to achieve the purpose of effective cure of tumors.
Sialic Acid Binding Immunoglobulin-like Lectins/metabolism* ; N-Acetylneuraminic Acid ; Immunoglobulins/metabolism* ; Receptors, Immunologic ; Ligands

Single chain antibody fragment (scFv) is a small molecule composed of a variable region of heavy chain (VH) and a variable region of light chain (VL) of an antibody, and these two chains are connected by a flexible short peptide. scFv is the smallest functional fragment with complete antigen-binding activity, which contains both the antibody-recognizing site and the antigen-binding site. Compared with other antibodies, scFv has the advantages of small molecular weight, strong penetration, low immunogenicity, and easy expression. Currently, the most commonly used display systems for scFv mainly include the phage display system, ribosome display system, mRNA display system, yeast cell surface display system and mammalian cell display system. In recent years, with the development of scFv in the field of medicine, biology, and food safety, they have also attracted much attention in the sectors of biosynthesis and applied research. This review summarizes the advances of scFv display systems in recent years in order to facilitate scFv screening and application.
Animals ; Immunoglobulin Variable Region/genetics* ; Immunoglobulin Fragments/metabolism* ; Single-Chain Antibodies/metabolism* ; Peptide Library ; Mammals/genetics*

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

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*

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