The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform
W H Lynch - One of the best experts on this subject based on the ideXlab platform.
-
instability of the major Soluble Antigen produced by renibacterium salmoninarum
Journal of Fish Diseases, 1991Co-Authors: S G Griffiths, W H LynchAbstract:. Using Western blot to examine the nature of Soluble Antigens produced by Renibacterium salmoninarum, it was found that the major 57-kilodalton (kDa) Antigen was unstable, SDS-PAGE of extracellular product (ECP) fractions showed that degradation of the 57-kDa protein increased with time and increased temperature. Several lower molecular mass pcptides accumulated temporarily from this degradation. Phenylmethylsulphonyl fluoride prevented breakdown of the 57-kDa protein suggesting a scrine protease present in the ECPs was responsible. The results indicated that most, if not all, immunoreactive bands in ECP fractions, other than the 57-kDa protein, arose as a result of degradation of this protein. Western blot analysis of two dimensional gels revealed that the presumptive proteolytic activity was associated with the 57-kDa Antigen and several of the apparent degradation products. Many common peptide fragments appeared to be generated from heat-induced proteolysis of these protein moieties, confirming the familial relationship between much of the immunoreactive material in ECP fractions. The results suggested that the 57-kDa Antigen is autolytic. Western blot analysis of tissue samples from Atlantic salmon, Satmo solar L., infected with R. salmoninarum suggested that this lability of the 57-kDa Antigen also occurred in situ.
James R. Winton - One of the best experts on this subject based on the ideXlab platform.
-
Molecular cloning and sequence analysis of the gene coding for the 57-kDa major Soluble Antigen of the salmonid fish pathogen Renibacterium salmoninarum.
FEMS Microbiology Letters, 1992Co-Authors: Maw-sheng Chien, Teresa Gilbert, Chienjin Huang, Marsha L. Landolt, Patrick J. O'hara, James R. WintonAbstract:The complete sequence coding for the 57-kDa major Soluble Antigen of the salmonid fish pathogen, Renibacterium salmoninarum, was determined. The gene contained an opening reading frame of 1671 nucleotides coding for a protein of 557 amino acids with a calculated Mr value of 57190. The first 26 amino acids constituted a signal peptide. The deduced sequence for amino acid residues 27–61 was in agreement with the 35 N-terminal amino acid residues determined by microsequencing, suggesting the protein in synthesized as a 557-amino acid precursor and processed to produce a mature protein of Mr 54505. Two regions of the protein contained imperfect direct repeats. The first region contained two copies of an 81-residue repeat, the second contained five copies of an unrelated 25-residue repeat. Also, a perfect inverted repeat (including three in-frame UAA stop codons) was observed at the carboxyl-terminus of the gene.
Berkland Cory - One of the best experts on this subject based on the ideXlab platform.
-
Soluble Antigen Arrays for Selective Desensitization of Insulin-Reactive B Cells
'American Chemical Society (ACS)', 2020Co-Authors: Leon, Martin A., Wemlinger, Scott M., Larson, Nicholas R., Ruffalo, Justin K., Middaugh C. Russell, Cambier, John C., Berkland CoryAbstract:This document is the Accepted Manuscript version of a Published Work that appeared in final form in Molecular Pharmaceutics, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.molpharmaceut.8b01250.Autoimmune diseases are believed to be highly dependent on loss of immune tolerance to self-Antigens. Currently, no treatments have been successful clinically in inducing autoAntigen-specific tolerance, including efforts to utilize Antigen-specific immunotherapy (ASIT) to selectively correct the aberrant autoimmunity. Soluble Antigen arrays (SAgAs) represent a novel autoAntigen delivery system composed of a linear polymer, hyaluronic acid (HA), displaying multiple copies of conjugated autoAntigen. We have previously reported that Soluble Antigen Arrays proteolipid protein (SAgAPLP) induced tolerance to a specific multiple sclerosis (MS) autoAntigen, proteolipid peptide (PLP). Utilizing SAgA technology, we have developed a new ASIT as a possible type 1 diabetes (T1D) therapeutic by conjugating human insulin to HA, known as Soluble Antigen Array Insulin (SAgAIns). Three types were synthesized: low valency lvSAgAIns (2 insulins per HA), medium valency mvSAgAIns (4 insulins per HA) and, high valency hvSAgAIns (9 insulins per HA) to determine if valency differentially modulates the ex vivo activity of insulin-binding B cells (IBCs). Extensive biophysical characterization was performed for the SAgA molecules. SAgAIns molecules were successfully used to affect the biologic activity of IBCs by inducing desensitization of the B cell Antigen receptors (BCR). SAgAIns bound specifically to insulin-reactive B cells without blocking epitopes recognized by antibodies against the Fc regions of membrane immunoglobulin or CD79 transducer components of the BCR. Pre-incubation of IBCs (125Tg) with SAgAIns, but not HA alone, rendered the IBCs refractory to re-stimulation. SAgAIns induced a decrease in BCR expression and IP3R-mediated intracellular calcium release. Surprisingly, SAgAIns binding to BCR on the surface of IBCs induced the observed effects at both high and low SAgAIns valency. Future studies aim to test the effects of SAgAIns on disease progression in the VH125.NOD mouse model of T1D.NIH T32 GM00854
-
Acute B-Cell Inhibition by Soluble Antigen Arrays Is Valency-Dependent and Predicts Immunomodulation in Splenocytes
'American Chemical Society (ACS)', 2020Co-Authors: Griffin J. Daniel, Leon, Martin A., Salash, Jean R., Shao Michael, Hartwell, Brittany L., Pickens, Chad J., Sestak, Joshua O., Berkland CoryAbstract:This document is the Accepted Manuscript version of a Published Work that appeared in final form in Biomacromolecules, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.biomac.9b00328.Antigen valency plays a fundamental role in directing the nature of an immune response to be stimulatory or tolerogenic. Soluble Antigen Arrays (SAgAs) are an Antigen-specific immunotherapy that combats autoimmunity through the multivalent display of autoAntigen. While mechanistic studies have shown SAgAs to induce T and B-cell anergy, the effect of SAgA valency has never been experimentally tested. Here, SAgAs of discrete Antigen valencies were synthesized by click chemistry and evaluated for acute B-cell signaling inhibition as well as downstream immunomodulatory effects in splenocytes. Initial studies using the Raji B-cell line demonstrated SAgA valency dictated the extent of calcium flux. Lower valency constructs elicited the largest reductions in B-cell activation. In splenocytes from mice with experimental autoimmune encephalomyelitis, the same valency-dependent effects were evident in the downregulation of the costimulatory marker CD86. The reduction of calcium flux observed in Raji B-cells correlated strongly with downregulation in splenocyte CD86 expression after 72 hours. Here, a thorough analysis of SAgA Antigenic valency illustrates that low, but not monovalent, presentation of autoAntigen was ideal for eliciting the most potent immunomodulatory effects.Madison and Lila Self Graduate Fellowship at the University of KansasNIH T32 GM00854
-
Soluble Antigen Arrays Displaying Mimotopes Direct the Response of Diabetogenic T Cells
'American Chemical Society (ACS)', 2020Co-Authors: Leon, Martin A., Pickens, Chad J., Fite, Rebuma Firdessa, Ruffalo, Justin Kristopher, Sestak, Joshua Orion, Creusot, Remi J., Berkland CoryAbstract:This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Chemical Biology, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acschembio.9b00090.Type 1 diabetes (T1D) is an autoimmune disorder which develops when insulin-producing, pancreatic beta cells are destroyed by an aberrant immune response. Current therapies for T1D either treat symptoms or cause global immunosuppression, which leave patients at risk of developing long-term complications or vulnerable to foreign pathogens. Antigen-specific immunotherapies have emerged as a selective approach for autoimmune diseases by inducing tolerance while mitigating global immunosuppression. We previously reported SAgAs with multiple copies of a multiple sclerosis (MS) autoAntigen grafted onto hyaluronic acid (HA) as an efficacious therapy in experimental autoimmune encephalomyelitis. While the immune response of MS is distinct from T1D, the mechanism of SAgAs was hypothesized to be similar and via induction of immune tolerance to diabetes Antigens. We synthesized SAgAs composed of HA polymer backbone conjugated with multiple copies of the T1D autoAntigen mimotope p79 using aminooxy chemistry (SAgAp79) or using copper-catalyzed alkyne-azide cycloaddition (cSAgAp79) chemistry. SAgAs constructed using the hydrolyzable aminooxy linkage, thus capable of releasing p79, exhibited physicochemical properties similar to the triazole linkage. Both SAgAp79 versions showed high specificity and efficacy in stimulating epitope-specific T cells. SAgAs can be taken up by most immune cell populations but do not induce their maturation, and conventional dendritic cells are responsible for the brunt of Antigen presentation within splenocytes. cSAgAp79 was more stimulatory than SAgAp79 both in vitro and in vivo, an effect that was ascribed to the peptide modification rather than the type of linkage. In summary, we provide here the first proof-of-principle that SAgA therapy could also be applicable to T1D.NIH T32 GM008545Juvenile Diabetes Research Foundation (2-SRA-2017-312-S-B)NIH Shared Instrumentation Grant # S10RR024664NSF Major Research Instrumentation Award # 1625923NIH S10OD020056Diabetes Research Center grant P30DK063608NIH HHSN272201300006
S G Griffiths - One of the best experts on this subject based on the ideXlab platform.
-
instability of the major Soluble Antigen produced by renibacterium salmoninarum
Journal of Fish Diseases, 1991Co-Authors: S G Griffiths, W H LynchAbstract:. Using Western blot to examine the nature of Soluble Antigens produced by Renibacterium salmoninarum, it was found that the major 57-kilodalton (kDa) Antigen was unstable, SDS-PAGE of extracellular product (ECP) fractions showed that degradation of the 57-kDa protein increased with time and increased temperature. Several lower molecular mass pcptides accumulated temporarily from this degradation. Phenylmethylsulphonyl fluoride prevented breakdown of the 57-kDa protein suggesting a scrine protease present in the ECPs was responsible. The results indicated that most, if not all, immunoreactive bands in ECP fractions, other than the 57-kDa protein, arose as a result of degradation of this protein. Western blot analysis of two dimensional gels revealed that the presumptive proteolytic activity was associated with the 57-kDa Antigen and several of the apparent degradation products. Many common peptide fragments appeared to be generated from heat-induced proteolysis of these protein moieties, confirming the familial relationship between much of the immunoreactive material in ECP fractions. The results suggested that the 57-kDa Antigen is autolytic. Western blot analysis of tissue samples from Atlantic salmon, Satmo solar L., infected with R. salmoninarum suggested that this lability of the 57-kDa Antigen also occurred in situ.
Hugh O Mcdevitt - One of the best experts on this subject based on the ideXlab platform.
-
intravenous injection of Soluble Antigen induces thymic and peripheral t cells apoptosis
Proceedings of the National Academy of Sciences of the United States of America, 1996Co-Authors: Roland S Liblau, Roland Tisch, Kevan M Shokat, Xiaodong Yang, Nicole Dumont, Christopher C Goodnow, Hugh O McdevittAbstract:The mechanism by which tolerance is induced via systemic administration of high doses of aqueous Antigen has been analyzed by using mice transgenic for a T-cell receptor specific for the influenza virus hemagglutinin (HA) peptide comprising amino acids 126-138. After intravenous injection of 750 (but not 75) micrograms of HA peptide, a state of hyporesponsiveness was rapidly induced. In the thymus, in situ apoptosis in the cortex and at the corticomedullary junction was responsible for a synchronous and massive deletion of CD4+ CD8+ thymocytes. In secondary lymphoid organs, HA-reactive T cells were initially activated but were hyporesponsive at the single cell level. After 3 days, however, those cells were rapidly deleted, at least partially, through an apoptotic process. Therefore, both thymic and peripheral apoptosis, in addition to T-cell receptor desensitization, contribute to high-dose tolerance.
