Search results for "Immunoglobulin M"
showing 10 items of 97 documents
Different Innate and Adaptive Immune Responses to SARS-CoV-2 Infection of Asymptomatic, Mild, and Severe Cases
2020
Abstract Background SARS-CoV-2 is a novel coronavirus, not encountered before by humans. The wide spectrum of clinical expression of SARS-CoV-2 illness suggests that individual immune responses to SARS-CoV-2 play a crucial role in determining the clinical course after first infection. Immunological studies have focussed on patients with moderate to severe disease, demonstrating excessive inflammation in tissues and organ damage. We have studied the individual response to SARS-CoV-2 of asympromatic, mild and severe COVID-19 patients in order to investigate the role of innnate and adaptive immunity in determining the clinical course after first infection. Methods To understand the basis of th…
The IgG1 B-cell receptor provides survival and proliferative signals analogue to the Igα but not the Igβ co-receptor.
2016
The function of the IgM B-cell receptor (BCR) is dependent on intact signaling of the co-receptors Igα and Igβ, both of which contain a cytoplasmic tail bearing an immunoreceptor tyrosine-based activation motif. We have previously demonstrated that the cytoplasmic tail of the IgG1 BCR can partially compensate for the loss of the signaling moiety of Igα. Here, we show that unlike Igα, Igβ signaling is indispensable for the development and function of IgG1-expressing B cells. Deletion of the cytoplasmic signaling tail of Igβ compromised the survival and proliferation not only of IgM(+) B cells but also of IgG1-expressing B cells. In the absence of the signaling tail of Igβ, the transcription …
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…
Subcutaneous injection of exosomes reduces symptom severity and mortality induced by Echinostoma caproni infection in BALB/c mice.
2016
Recent studies have shown the importance of exosomes in the host-parasite relationship. These vesicles are an important part of the excretory/secretory pathway for proteins with the potential to alter immune responses. Therefore, in the present study, we examined the immunomodulatory role of exosomes in BALB/c mice using Echinostoma caproni as an experimental model of intestinal helminth infection. For this purpose, BALB/c mice were injected twice s.c. with purified exosomes of E. caproni, followed by experimental infection. We report a delay in the development of the parasite in mice immunised with exosomes, a concomitant reduced symptom severity and increased survival upon infection. Immu…
Significance of chronic toxoplasmosis in epidemiology of road traffic accidents in Russian Federation
2017
Studies carried out in Moscow residents have revealed that the prevalence of chronic toxoplasmosis is very close to those in countries of Eastern and Central Europe. Our findings also demonstrated a statistically significant relationship between the rate of traffic accidents and the seroprevalence of chronic toxoplasmosis in drivers who were held responsible for accidents. The latter was 2.37 times higher in drivers who were involved in road accidents compared with control groups. These results suggest that the consequences of chronic toxoplasmosis (particularly a slower reaction time and decreased concentration) might contribute to the peculiarities of the epidemiology of road traffic acci…
A Naturally Occurring Antibody Fragment Neutralizes Infectivity of Diverse Infectious Agents
2016
AbstractA phosphorylated peptide, named K40H, derived from the constant region of IgMs was detected in human serum by liquid chromatography coupled to high-resolution mass spectrometry. Synthetic K40H proved to exert a potent in vitro activity against fungal pathogens, and to inhibit HIV-1 replication in vitro and ex vivo. It also showed a therapeutic effect against an experimental infection by Candida albicans in the invertebrate model Galleria mellonella. K40H represents the proof of concept of the innate role that naturally occurring antibody fragments may exert against infectious agents, shedding a new light upon the posthumous role of antibodies and opening a new scenario on the multif…
Oleanane-type glycosides from the roots of Weigela florida “rumba” and evaluation of their antibody recognition
2018
Three triterpene glycosides were isolated from the roots of Weigela florida "rumba" (Bunge) A. DC.: two previously undescribed 3-O-β-d-xylopyranosyl-(1→2)-[β-d-xylopyranosyl-(1→4)]-β-d-xylopyranosyl-(1→4)-β-d-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyloleanolic acid (1) and 3-O-β-d-xylopyranosyl-(1→2)-[β-d-glucopyranosyl-(1→4)]-β-d-xylopyranosyl-(1→4)-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid (2), and one isolated for the first time from a natural source 3-O-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyloleanolic acid (3). Their structures were elucidated mainly by 2D NMR spectroscopic analysis (COSY, …
Multiple organ failure as onset of Mediterranean spotted fever: a review based on a case
2016
Mediterranean spotted fever (MSF) is an infectious disease endemic in the southern regions of Italy, with an incidence of about 400 cases/year. The bacteria responsible of the disease is <em>Rickettsia conorii</em>, transmitted to humans by <em>Rhipicephalus sanguineus</em>, the common dog tick. The infection usually manifests with a characteristic symptomatologic triad: fever, exanthema and the so called <em>tache noire</em>, which is the typical eschar at the site of the tick bite. Immunoglobulin M (IgM) and IgG enzymelinked immunosorbent assay and the gold standard micro-immunofluorescent assay, allow serological diagnosis. We report the case of a man …
Development of a Sensitive Detection Method for Alphaviruses and Its Use as a Virus Neutralization Assay
2021
Alphaviruses have a single-stranded, positive-sense RNA genome that contains two open reading frames encoding either the non-structural or the structural genes. Upon infection, the genomic RNA is translated into the non-structural proteins (nsPs). NsPs are required for viral RNA replication and transcription driven from the subgenomic promoter (sgP). Transfection of an RNA encoding the luciferase gene under the control of the sgP into cells enabled the detection of replication-competent chikungunya virus (CHIKV) or Mayaro virus (MAYV) with high sensitivity as a function of the induced luciferase activity. This assay principle was additionally used to analyze virus-neutralizing antibodies in…
Celiac disease and selective immunoglobulin A deficiency
1997
Selective IgA deficiency was observed in 12 of 688 (1.7%) patients with celiac disease who were clinically undistinguishable from patients with celiac disease with normal IgA levels. This high prevalence of IgA deficiency in patients with celiac disease makes serum IgA assay advisable when screening for celiac disease is performed by measurement of antigliadin antibodies or anti-IgA endomysium antibodies. Similarly, subjects with IgA deficiency should be considered at risk of celiac disease.