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PROVIDER: PRJNA988832 | ENA |
REPOSITORIES: ENA
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Project description:Intestinal ischemia-reperfusion (IR) injury is initiated when natural IgM antibodies recognize neo-epitopes that are revealed on ischemic cells. The target molecules and mechanisms whereby these neo-epitopes become accessible to recognition are not well understood. Proposing that isolated intestinal epithelial cells (IEC) may carry IR-related neo-epitopes, we used in vitro IEC binding assays to screen hybridomas created from B cells of unmanipulated wild type C57BL/6 mice. We identified a novel IgM monoclonal antibody (mAb B4) that reacted with the surface of IEC by flow cytometric analysis and was alone capable of causing complement activation, neutrophil recruitment and intestinal injury in otherwise IR-resistant Rag1-/- mice. Monoclonal Ab B4 was found to specifically recognize mouse annexin IV. Pre-injection of recombinant annexin IV blocked IR injury in wild type C57BL/6 mice, demonstrating the requirement for recognition of this protein in order to develop IR injury in the context of a complex natural antibody repertoire. Humans were also found to exhibit IgM natural antibodies that recognize annexin IV. These data in toto identify annexin IV as a key ischemia-related target antigen that is recognized by natural Abs in a pathologic process required in vivo to develop intestinal IR injury. Keywords: Natural antibodies, Annexin, Ischemia Reperfusion, Inflammation, Complement In the study presented here, a total of 4 custom spotted antigen slides were hybridized with known antibodies.
2010-05-05 | E-GEOD-14862 | biostudies-arrayexpress
Project description:Intestinal ischemia-reperfusion (IR) injury is initiated when natural IgM antibodies recognize neo-epitopes that are revealed on ischemic cells. The target molecules and mechanisms whereby these neo-epitopes become accessible to recognition are not well understood. Proposing that isolated intestinal epithelial cells (IEC) may carry IR-related neo-epitopes, we used in vitro IEC binding assays to screen hybridomas created from B cells of unmanipulated wild type C57BL/6 mice. We identified a novel IgM monoclonal antibody (mAb B4) that reacted with the surface of IEC by flow cytometric analysis and was alone capable of causing complement activation, neutrophil recruitment and intestinal injury in otherwise IR-resistant Rag1-/- mice. Monoclonal Ab B4 was found to specifically recognize mouse annexin IV. Pre-injection of recombinant annexin IV blocked IR injury in wild type C57BL/6 mice, demonstrating the requirement for recognition of this protein in order to develop IR injury in the context of a complex natural antibody repertoire. Humans were also found to exhibit IgM natural antibodies that recognize annexin IV. These data in toto identify annexin IV as a key ischemia-related target antigen that is recognized by natural Abs in a pathologic process required in vivo to develop intestinal IR injury. Keywords: Natural antibodies, Annexin, Ischemia Reperfusion, Inflammation, Complement
2009-02-19 | GSE14862 | GEO
Project description:Natural antibodies, which arise without known immune exposure, have been described that specifically recognize cells dying from apoptosis but their role in innate immunity remains poorly understood. Herein, we show that the immune response to neo-antigenic determinants on apoptotic thymocytes is dominated by antibodies to oxidation-associated antigens, phosphorylcholine (PC), a head group that becomes exposed during programmed-cell death, and malondialdehyde (MDA), a reactive aldehyde degradation product of polyunsaturated lipids produced following exposure to reactive-oxidation species. While natural antibodies to apoptotic cells in naM-CM-/ve adult mice were dominated by PC and MDA specificities, the amounts of these antibodies were substantially boosted by treatment of mice with apoptotic cells. Moreover, the relative amounts of PC and MDA antibodies was affected by VH gene inheritance. Antibody interactions with apoptotic-cells also mediated the recruitment of C1q, which alone can promote apoptotic-cell phagocytosis by immature dendritic cells. Significantly, IgM-antibodies to both PC and MDA were primary factors in determining the efficiency of serum-dependent apoptotic-cell phagocytosis. Hence, we demonstrate a mechanism by which certain natural antibodies that recognize neo-antigens on apoptotic cells, in naM-CM-/ve mice and those induced by immune exposure to apoptotic-cells, can enhance the functional capabilities of immature dendritic cells for phagocytic engulfment of apoptotic cells. Keywords: Natural antibodies, Inflammation, Complement, Apoptosis In the study presented here, a total of 11 custom-spotted protein slides were hybridized with a T15 IgM monoclonal antibody at three different concentrations, an isotype control IgM, 2 slides were hybridized with serum from naM-QM-^Wve mice, 2 slides incubated with serum from mice immunized with apoptotic cells, 2 slides were incubated with serum from mice immunized with saline, and a negative control slide with no antibody hybridized
2009-02-23 | E-GEOD-14958 | biostudies-arrayexpress
Project description:Human serum IgM antibodies are composed of heavily glycosylated polymers with five glycosylation sites on the μ (heavy) chain and one glycosylation site on the J chain. In contrast to IgG glycans, which are vital for a number of biological functions, virtually nothing is known about structure-function relationships of IgM glycans. Natural IgM is the earliest immunoglobulin produced and recognizes multiple antigens with low affinity, whilst immune IgM is induced by antigen exposure and is characterized by a higher antigen specificity. Natural anti-lymphocyte IgM is present in the serum of healthy individuals and increases in inflammatory conditions. It is able to inhibit T cell activation, but the underlying molecular mechanism is not understood. Here we show, for the first time, that sialylated N-linked glycans induce the internalization of IgM by T cells, which in turn causes severe inhibition of T cell responses. The absence of sialic acid residues abolishes these inhibitory activities, showing a key role of sialylated N-glycans in inducing the IgM-mediated immune suppression.
2014-11-11 | E-MTAB-3030 | biostudies-arrayexpress
Project description:Endogenous retroviruses (ERV), comprising a substantial portion of the vertebrate genome, are remnants of ancient genetic invaders. ERV with near-intact coding potential reactivate in B cell-deficient mice. Here, we employed an antigen-baiting strategy to enrich B cells reactive to ERV surface antigens. We identified ERV-reactive B-1 cells expressing germline-encoded natural IgM antibodies in naïve mice, the level of which further increases upon innate immune sensor stimulation. B cell receptor repertoire profiling of ERV-reactive B-1 cells revealed increased usage of Igh VH gene that gives rise to glycan-specific antibodies targeting terminal N-acetylglucosamine moieties on ERV glycoproteins, which further engage the complement pathway to protect the host from ERV emergence. These same antibodies also recognize glycoproteins of other enveloped viruses, but not self-proteins. These results reveal an innate antiviral mechanism of germline-encoded antibodies with broad reactivity to enveloped viruses, whose absence leads to the emergence of infectious ERV.
2023-07-01 | GSE207247 | GEO
Project description:Natural antibodies, which arise without known immune exposure, have been described that specifically recognize cells dying from apoptosis but their role in innate immunity remains poorly understood. Herein, we show that the immune response to neo-antigenic determinants on apoptotic thymocytes is dominated by antibodies to oxidation-associated antigens, phosphorylcholine (PC), a head group that becomes exposed during programmed-cell death, and malondialdehyde (MDA), a reactive aldehyde degradation product of polyunsaturated lipids produced following exposure to reactive-oxidation species. While natural antibodies to apoptotic cells in naïve adult mice were dominated by PC and MDA specificities, the amounts of these antibodies were substantially boosted by treatment of mice with apoptotic cells. Moreover, the relative amounts of PC and MDA antibodies was affected by VH gene inheritance. Antibody interactions with apoptotic-cells also mediated the recruitment of C1q, which alone can promote apoptotic-cell phagocytosis by immature dendritic cells. Significantly, IgM-antibodies to both PC and MDA were primary factors in determining the efficiency of serum-dependent apoptotic-cell phagocytosis. Hence, we demonstrate a mechanism by which certain natural antibodies that recognize neo-antigens on apoptotic cells, in naïve mice and those induced by immune exposure to apoptotic-cells, can enhance the functional capabilities of immature dendritic cells for phagocytic engulfment of apoptotic cells. Keywords: Natural antibodies, Inflammation, Complement, Apoptosis
2009-02-23 | GSE14958 | GEO
Project description:One of the most common genetic backgrounds for mice used as model to investigate human diseases is the BALB/c strain. This work is aimed to characterize the pattern of natural anti-carbohydrate antibodies present in serum of BALB/c mice by printed glycan array technology. Natural antibodies from serum of BALB/c mice interacted with at least 70 glycans from a library of 419 different carbohydrate structures. However, only a restricted number of these (12, ~17%) were highly recognized by natural antibodies, and shared by more than 80% of mice under examination. This conserved pattern differed dramatically from that of humans. This finding together with not identical repertoires of antibodies between individual mice should be specially considered when mouse models are intended to be used for investigation of human natural antibodies in different biomedical research and diagnostic contexts.
2017-03-29 | GSE97151 | GEO
Project description:Although natural antibodies (NAbs) are present from birth, little is known about what drives their selection, and whether they have housekeeping functions. We now show that the prototypic T15-NAb, first identified because of its protective role in infection, is representative of a previously unknown type of NAb response that specifically recognizes and forms complexes with apoptotic cells, and which promotes cell-corpse engulfment by phagocytes. This T15-NAb-mediated process is dependent on the recruitment of C1q and mannose-binding lectin (MBL), which have known immune modulatory activities that also provide âeat meâ signals for phagocytic clearance. Further investigation revealed that, the addition of T15-NAb significantly suppressed in vitro macrophage LPS-induced TNF-alpha and IL-6 secretion, as well as in vitro Toll-like receptor (TLR)-induced dendritic cell maturation and secretion of pro-inflammatory cytokines and chemokines. Significantly, high doses of this B-1 cell produced NAb also inhibited in vivo TLRâinduced pro-inflammatory responses, and could suppress autoimmune inflammatory arthritis. These studies identify and characterize a previously unknown regulatory circuit by which a NAb product of innate-like B cells aids homeostasis by control of fundamental inflammatory pathways. Keywords: Dendritic cells, Macrophages, Natural Antibodies, Apoptosis, Inflammation, Arthritis In the study presented here, a total of 15 custom-spotted protein slides were hybridized with a T15 IgM monoclonal antibody at three different concentrations, an isotype control IgM, 2 slides were hybridized with serum from naÑve mice, 2 slides incubated with serum from mice immunized with apoptotic cells, 2 slides were incubated with serum from mice immunized with saline, 2 slides were incubated with serum from mice injected with T15 IgM monoclonal antibody, 2 slides were incubated with serum from a lupus-prone mouse disease model and a negative control slide with no antibody hybridized
2010-05-06 | E-GEOD-14969 | biostudies-arrayexpress
Project description:Origins of genetic exchange in Leishmania parasites
| PRJNA788482 | ENA