IgG purification- MS analysis - MS analysis was undertaken on human IgG purified using different approaches to assess purifity and potential alterations within the IgG N-linked glycans
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ABSTRACT:
INSTRUMENT(S):
ORGANISM(S): Homo Sapiens (human)
SUBMITTER: 
Nichollas Scott
LAB HEAD: Amy Chung
PROVIDER: PXD014235 | Pride | 2019-11-01
REPOSITORIES: Pride
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Project description:Immunoglobulin G (IgG) molecules modulate an immune response. However, site-specific N-glycosylation signatures of plasma IgG in patients with chronic kidney disease (CKD) remain unclear. This study aimed to propose a novel method to explore the N-glycosylation pattern of IgG and to compare it with reported methods. We separated human plasma IgG from 58 healthy controls (HC) and 111 patients with CKD. Purified IgG molecules were digested by trypsin. Tryptic peptides with-out enrichment were analyzed using a combination of electron-transfer/higher-energy collisional dissociation (EThcD) and stepped collision energy/higher-energy collisional dissociation (sceHCD) mass spectrometry (EThcD-sceHCD-MS/MS). This resulted in higher spectral quality, more informative fragment ions, higher Byonic score, and nearly twice the depth of intact N-glycopeptide identification than sceHCD or EThcD alone. Site-specific N-glycosylation mapping revealed that intact N-glycopeptides were differentially expressed in HC and CKD patients; thus, it can be a diagnostic tool. This study provides a method for the determination of glycosylation patterns in CKD and a framework for understanding the role of IgG in the pathophysiology of CKD.
2021-11-25 | PXD027174 | Pride
Project description:Changes in IgG glycosylation have been reported to be associated with colorectal cancer (CRC), but the alteration in specific subclass of IgG is unknown. Herein, we optimized five common IgG glycopeptides enrichment methods to acquire comprehensive profiling of IgG glycoproteomics in CRC. Notably, incomplete tryptic digestion of IgG occurred when using ordinary ratio of protease to protein, which significantly impacted the final statistical analysis of association between IgG glycosylation and CRC. We introduced a method based on two-step enzymatic digestion, enabling the complete digestion of IgG glycopeptides and further improving the detection intensity of the target glycopeptides. By this approach, total 47 IgG glycopeptides can be identified by nanoLC-ESI-MS/MS. Following rapid and automatic data processing through the self-developed program, we observed that IgG1_H3N4F1 and IgG1_H3N4 were substantially increased in CRC, while IgG1_H5N5F1, IgG1_H5N4F1S1and IgG2_H5N4F1 were markedly decreased. Strikingly, these four glycopeptides were continually significantly changed in early and late stages of CRC. Further evaluation of the diagnostic performance showed they all obtained a fair performance in discriminating the patients from the normal. In terms of the glycan features, it demonstrated that CRC progression associates with the increased agalactosylation, and the decreased digalactosylation and galactosylation per antenna on diantennay glycans of IgG1 and IgG2. Concurrently, the decreased sialylation of IgG1 was strongly correlated with CRC. Moreover, tumor-specific glycosylation analysis showed that the alterations of subclass-specific IgG glycosylation were more significant in colon cancer, and no obvious difference between colon and rectal cancer was found. More importantly, all these findings were validated in an independent cohort. This two-step enzymatic approach is crucial to explore the relationship between the disease progression and IgG glycosylation.
2022-10-27 | PXD016318 | Pride
Project description:Chronic inflammatory and immune dysregulation are critical drivers in the development and progression of chronic obstructive pulmonary disease (COPD). Posttranslational modifications, such as glycosylation of Immunoglobulin G (IgG), modulates systemic inflammatory homeostasis. This study aims to profile plasma IgG glycopeptides (IgGPs) in COPD patients to uncover new insights into its pathogenesis and to identify novel biomarkers. Plasma IgG N-glycopeptides from 90 COPD patients, 45 clinical defined early COPD (CECOPD) patients and 90 healthy individuals were analyzed using an integrated platform that combines Fe3O4@PDA@DETA nanospheres enrichment with high-resolution mass spectrometry measurement. Correlations between IgG N-glycoforms and clinical parameters were assessed to explore underlying mechanisms of COPD progression. Disease-specific IgGPs were identified in both ECOPD and COPD cohorts. Notably, IgG glyco-pattern, rather than IgG levels, changed with disease progression. Early COPD patients showed decreased bisection and increased site-specific afucosylated galactosylation and fucosylation of IgG, indicating an anti-inflammatory state. In contrast, COPD patients gave increased inflammation, characterized by reduced galactosylation and sialylation. Interestingly, a subset of healthy controls displayed IgGPs patterns similar to early COPD, possibly reflecting the impact of substantial smoking exposure and associated immune responses. These findings suggest that plasma IgG glycosylation could serve as a potential biomarker for early COPD diagnosis, providing valuable insights into immune system changes during disease progression.
2025-05-07 | PXD056374 | Pride
Project description:Immunoglobulins G (IgG) and their Fc gamma receptors (FcγRs) play important roles in our immune system. The conserved N-glycan in the Fc region of IgG1 impacts interaction of IgG with FcγRs and the resulting effector functions, which has led to design of antibody therapeutics with greatly improved antibody-dependent cell cytotoxicity (ADCC) activities. Studies have suggested that also N-glycosylation of the FcγRIII affects receptor inteactions with IgG, but detailed studies of the interaction of IgG1 and FcγRIIIa with distinct N-glycans have been hindered by the natural heterogeneity in N-glycosylation. In this study, we employed comprehensive genetic engineering of the N-glycosylation capacities in mammalian cell lines to express IgG1 and FcγRIIIa with different N-glycan structures to more generally explore the role of N-glycosylation in IgG1:FcRIIIa binding interactions. We included FcRIIIa variants of both the 158F and 158V allotypes and investigated the key N-glycan features that affected binding affinity. Our study confirms that afucosylated IgG1 has the highest binding affinity to oligomannose FcγRIIIa, a glycan structure commonly found on FcγRIIIa expressed by NK cells but not monocytes or recombinantly expressed FcγRIIIa.
2022-08-30 | PXD035846 | Pride
Project description:Background: Alterations in IgG glycosylation have been observed in many inflammatory activities and diseases progression, uncovering IgG glycome contributes to deciphering the molecular mechanism of human diseases. Gastric cancer (GC) associated IgG glycosylation was rarely investigated.Methods: We comprehensively characterized IgG N-glycome profile in GC by high-throughput orthogonal mass spectrometry assay, and analyzed the difference of glycosylation between controls and GC patients through multiple statistical tools. Bioinformatics analysis was performed to study the candidate glycogens and their biological functions involved in GC. Results: GC associates with decrease in galactosylation and sialylation of IgG, and increase in bisection and agalactosylation of IgG.Bioinformatics analysis verified the differential expression of significantly changed IgG glycan associated glycogens, indicating the crucial role of IgG glycosylation in the pathogenesis of GC.Conclusions: This study demonstrates the potential diagnostic merits of specific IgG glycans for early detection of GC, as well as revealing molecular mechanism in the development of this cancer.
2025-05-06 | PXD028368 | Pride
Project description:Maternal IgG is an immunoglobulin present in breast milk and has been shown to play a role in the development of the immune system in infants. The aim of this study was to investigate the effects of maternal IgG on brain development in mouse pups. Maternal IgG immunoreactivity was observed in microglial cells of the pup brain, peaking at postnatal 8 day. In particular, strong IgG immunoreactivity was observed in the microglia in the corpus callosum and cerebellar white matter. IgG stimulation of primary cultured microglia resulted in activation of the type I interferon feedback loop by Syk. Among the IgG subclasses, IgG2a was found to have a strong influence on microglia. Analysis of FcRn KO mice that were unable to take up IgG from their mothers revealed that these mice had abnormalities in the proliferation and/or survival of microglia, oligodendrocytes, and some types of interneurons. FcRn KO mice also exhibited abnormalities in social behavior and adaptation to novel environments. This study suggests that maternal IgG affects brain development in pups.
2024-05-24 | GSE248310 | GEO
Project description:Background:Gastric cancer (GC) is one of the most aggressive gastrointestinal malignancy and leading cause of cancer related deaths worldwide,warranting the urgent discovery of biomarkers for early detection. IgG glycosylation is strongly related to disease progression and specific IgG glycans have been regarded as the next-generation biomarker, whereas it is rarly studied on the association between subclass-specific IgG glycosylation profile and GC progression. Methods:A total of 141 individuals were enrolled and randomly sorted into discovery set consisting of normal (N=30) and cancer patients (N=20), and validation set including controls (N=30), benign (N=25) and cancer (N=36).IgG glycopeptides were tryptic digested and enrichmed by microcrystalline cellulose based solid phase extraction.Subclass-specific IgG N-glycosylation was analyzed by nanoLC-MS/MS. Results:It was found that GC progression was associated with increased sialylation and decreased bisection of IgG2, as well as substantially decreased sialylation of IgG1 and increased galactosylation of IgG3/4.Further analysis of individual glycopeptides showed the changes of particular glycosylation of IgGwere reflected by the specific glycans taht could apparently distinguish different stages of gastric disease patients from normal. Conclusions:Different subclasses of IgG glycosylation were differentially expressed in GC, specific IgG glycopeptides could be promising biomarker for early detection of GC patients.
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Project description:Saliva based diagnostics is a rapidly evolving field due to the large potential of saliva and the simple sample collection. A systematic comparison of IgG antibody profiles in saliva and plasma is currently lacking in scientific literature. Our hypothesis is that IgG profiles are equal in blood and saliva. By showing the equality of the profiles and relative IgG antigenic reactivities towards proteins and peptides we provide evidence that plasma IgG reactivities can be inferred from saliva IgG reactivities. IgG antibodies were isolated from human saliva and plasma samples. The reactivities of IgG isolates were analysed on peptide microarrays displaying linear epitopes of EBV (EBNA1 protein) and HBV (Large envelope protein) virus. Peptide arrays were printed by JPT Peptide Technologies (Berlin, Germany). We show high similarity of saliva and plasma IgG profiles on these two platforms and argue for generalisation from this subset to the whole immunological IgG antibody profile.
2018-07-17 | GSE117140 | GEO
Project description:Saliva based diagnostics is a rapidly evolving field due to the large potential of saliva and the simple sample collection. A systematic comparison of IgG antibody profiles in saliva and plasma is currently lacking in scientific literature. Our hypothesis is that IgG profiles are equal in blood and saliva. By showing the equality of the profiles and relative IgG antigenic reactivities towards proteins and peptides we provide evidence that plasma IgG reactivities can be inferred from saliva IgG reactivities. IgG antibodies were isolated from human saliva and plasma samples. The reactivities of IgG isolates were analysed on peptide microarrays displaying linear epitopes of EBV (EBNA1 protein) and HBV (Large envelope protein) virus. Peptide arrays were printed by JPT Peptide Technologies (Berlin, Germany). We show high similarity of saliva and plasma IgG profiles on these two platforms and argue for generalisation from this subset to the whole immunological IgG antibody profile.
2018-07-17 | GSE117141 | GEO
Project description:The transplacental transfer of maternal IgG to the developing fetus is critical for infant protection against infectious pathogens in the first year of life. However, factors that modulate the transplacental transfer efficiency of maternal IgG that could be harnessed for maternal vaccine design remain largely undefined. HIV-infected women have impaired placental IgG transfer, yet the mechanism underlying this impaired transfer is unknown, presenting an opportunity to explore factors that contribute to the efficiency of placental IgG transfer. We measured the transplacental transfer efficiency of maternal HIV and other pathogen-specific IgG in historical U.S. (n=120) and Malawian (n=47) cohorts of HIV-infected mothers and their HIV58 exposed uninfected and HIV-infected infants. We then examined the role of maternal HIV disease progression, infant factors, placental Fc receptor expression, and IgG Fc region subclass and glycan signatures and their association with transplacental transfer efficiency of maternal antigen-specific IgG. We established 3 distinct phenotypes of placental IgG transfer efficiency in HIV-infected women, including: 1) efficient transfer of the majority of antigen-specific IgG populations; 2) generally poor IgG transfer phenotype that was strongly associated with maternal CD4+ T cell counts, hypergammaglobulinemia, and frequently yielded non-protective levels of vaccine-specific IgG; and 3) variable transfer of IgG across distinct antigen specificities. Interestingly, maternal IgG characteristics, such as binding to placentally expressed Fc receptors FcgRIIa and FcgRIIIa, IgG subclass frequency, and Fc region glycan profiles were associated with placental IgG transfer efficiency. These maternal IgG transplacental transfer determinants were distinct among different antigen-specific IgG populations. Our findings suggest that in HIV-infected women, both maternal disease progression and Fc region characteristics modulate the selective placental transfer of distinct IgG subpopulations, with implications for both the health of HIV-exposed uninfected infants and maternal vaccine design.
2019-09-11 | GSE129272 | GEO