Search results for "Antibody Affinity"
showing 10 items of 16 documents
The future of Extracellular Vesicles as Theranostics – an ISEV meeting report
2020
ABSTRACT The utilization of extracellular vesicles (EVs) in clinical theranostics has rapidly advanced in the past decade. In November 2018, the International Society for Extracellular Vesicles (ISEV) held a workshop on “EVs in Clinical Theranostic”. Here, we report the conclusions of roundtable discussions on the current advancement in the analysis technologies and we provide some guidelines to researchers in the field to consider the use of EVs in clinical application. The main challenges and the requirements for EV separation and characterization strategies, quality control and clinical investigation were discussed to promote the application of EVs in future clinical studies.
Specificity of human natural antibodies referred to as anti-Tn
2020
International audience; To understand the role of human natural IgM known as antibodies against the carbohydrate epitope Tn, the antibodies were isolated using GalNAcα−Sepharose affinity chromatography, and their specificity was profiled using microarrays (a glycan array printed with oligosaccharides and bacterial polysaccharides, as well as a glycopeptide array), flow cytometry, and inhibition ELISA. The antibodies bound a restricted number of GalNAcα-terminated oligosaccharides better than the parent monosaccharide, e.g., 6-O-Su-GalNAcα and GalNAcα1−3Galβ1−3(4)GlcNAcβ. The binding with several bacterial polysaccharides that have no structural resemblance to the affinity ligand GalNAcα was…
Hepatitis B surface antigen presentation and HLA-DRB1*– lessons from twins and peptide binding studies
2005
Summary The aim of this study was to investigate the underlying mechanisms of the genetic association between certain HLA-DRB1* alleles and the immune response to HBsAg vaccination. Therefore, HBsAg peptide binding to HLA-DR molecules was measured in vitro by peptide binding ELISAs. Additionally, HBsAg-specific T cell reaction and cytokine profile of immune response were analysed ex vivo in ELISPOT assays and DR-restriction of T-cell proliferative responses was investigated with HBsAg specific T cell clones. In addition, we compared HBsAg specific T cell responses of 24 monozygotic and 3 dizygotic twin pairs after HBsAg vaccination. Our results showed that the peptide binding assays did not…
Qualitative assessment of SARS-CoV-2-specific antibody avidity by lateral flow immunochromatographic IgG/IgM antibody assay.
2020
Abstract Knowledge of the precise timing of SARS‐CoV‐2 infection may be of clinical and epidemiological relevance. The presence of low‐avidity IgGs has conventionally been considered an indicator of recent infection. Here, we carried out qualitative assessment of SARS‐CoV‐2‐specific antibody avidity using an urea (6M) dissociation test performed on a lateral flow immunochromatographic IgG/IgM device. We included a total of 76 serum specimens collected from 57 COVID‐19 patients, of which 39 tested positive for both IgG and IgM and 37 only for IgG. Sera losing IgG reactivity after urea treatment (n = 28) were drawn significantly earlier (P = .04) after onset of symptoms than those which prese…
Early neutralizing and glycoprotein B (gB)-specific antibody responses to human cytomegalovirus (HCMV) in immunocompetent individuals with distinct c…
2000
Abstract Background: Antibodies with functional anti-Human Cytomegalovirus (HCMV) activity are likely to be involved in preventing virus dissemination and thus may contribute to minimize the clinical manifestations of infection. Objectives: To investigate the role of humoral immunity in modulating the clinical expression of primary Human Cytomegalovirus (HCMV) infection in immunocompetent persons. Study design: Neutralizing (NA) and glycoprotein B (gB)-specific antibodies were quantitated in acute-phase and late-convalescence phase sera from 19 individuals who developed either HCMV mononucleosis (12) or oligosymptomatic hepatitis (seven). Results: The levels of NA in sera drawn early after …
Mepanipyrim haptens and antibodies with nanomolar affinity
2013
Mepanipyrim is an anilinopyrimidine fungicide used worldwide for crop protection. With the aim of developing useful immunoreagents for mepanipyrim immunoanalysis, two new functionalized derivatives were prepared and antibodies were generated. Affinity and specificity were assessed by direct and indirect competitive ELISA using homologous and heterologous conjugates. Although all antibodies were selective for the target analyte, the immunizing hapten structure was revealed as a determinant for high-affinity antibody production (IC50 = 3 nM). © 2013 The Royal Society of Chemistry.
Exploring alternative hapten tethering sites for high-affinity anti-picoxystrobin antibody generation
2011
The relevance of the linker tethering site in haptens was investigated for antibody generation and immunoassay development. Three derivatives of the strobilurin fungicide picoxystrobin were synthesized with the same functionalized spacer arm located at three different positions. Protein conjugates of those haptens were employed as immunogens, and novel polyclonal antibodies were produced and characterized. All haptens afforded highly specific antibodies, but different affinities to the free analyte were observed among the obtained antisera. Next, competitive enzyme-linked immunosorbent assays were studied in several formats, and site heterology was confirmed as an effective strategy for det…
IL-21 Regulates the Differentiation of a Human γδ T Cell Subset Equipped with B Cell Helper Activity
2012
Vγ9Vδ2 T lymphocytes recognize nonpeptidic antigens without presentation by MHC molecules and display pleiotropic features. Here we report that coculture of Vγ9Vδ2 cells with phosphoantigen and IL-21 leads to selective expression of the transcription repressor Bcl-6 and polarization toward a lymphocyte subset displaying features of follicular B-helper T (T(FH)) cells. T(FH) like Vγ9Vδ2 cells have a predominant central memory (CD27(+)CD45RA(-)) phenotype and express ICOS, CD40L and CXCR5. Upon antigen activation, they secrete IL-4, IL-10 and CXCL13, and provide B-cell help for antibody production in vitro. Our findings delineate a subset of human Vγ9Vδ2 lymphocytes, which, upon interaction w…
Maturation of IgG avidity to individual rubella virus structural proteins.
2001
Background: the structural proteins of rubella virus, the capsid protein C and the envelope glycoproteins E1 and E2 were produced in lepidopteran insect cells using baculovirus expression vectors. The C-terminal ends of the corresponding proteins were fused to a polyhistidine tag for easy and gentle purification by metal ion affinity chromatography. Objectives: to investigate the maturation of natural and vaccinal IgG avidity against individual authentic and recombinant rubella virus (RV) structural proteins. Study design the analysis was carried out using a modified immunoblotting technique where the purified baculovirus-expressed proteins were compared with authentic rubella virus protein…
Impact of a Three Amino Acid Deletion in the CH2 Domain of Murine IgG1 on Fc-Associated Effector Functions
2008
Abstract Four murine IgG subclasses display markedly different Fc-associated effector functions because of their differential binding to three activating IgG Fc receptors (FcγRI, FcγRIII, and FcγRIV) and C1q. Previous analysis of IgG subclass switch variants of 34-3C anti-RBC monoclonal autoantibodies revealed that the IgG1 subclass, which binds only to FcγRIII and fails to activate complement, displayed the poorest pathogenic potential. This could be related to the presence of a three amino acid deletion at positions 233–235 in the CH2 domain uniquely found in this subclass. To address this question, IgG1 insertion and IgG2b deletion mutants at positions 233–235 of 34-3C anti-RBC Abs were …