Search results for "molecular mimicry"
showing 10 items of 40 documents
DYSMICROBISM, INFLAMMATORY BOWEL DISEASE AND THYROIDITIS: ANALYSIS OF THE LITERATURE
2015
The human body is colonized by a large number of microbes that are collectively referred to as the microbiota. They interact with the hosting organism and some do contribute to the physiological maintenance of the general good health thru regulation of some metabolic processes while some others are essential for the synthesis of vitamins and short-chain fatty acids. The abnormal variation, in the quality and/or quantity of individual bacterial species residing in the gastro-intestinal tract, is called dysmicrobism. The immune system of the host will respond to these changes at the intestinal mucosa level which could lead to Inflammatory Bowel Diseases (IBD). This inflammatory immune respo…
Does SARS-CoV-2 Trigger Stress-InducedAutoimmunity by Molecular Mimicry? A Hypothesis.
2020
Viruses can generate molecular mimicry phenomena within their hosts. Why shouldsevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) not be considered one of these?Information in this short review suggests that it might be so and, thus, encourages research aimingat testing this possibility. We propose, as a working hypothesis, that the virus induces antibodiesand that some of them crossreact with host’s antigens, thus eliciting autoimmune phenomena withdevasting consequences in various tissues and organs. If confirmed, by in vitro and in vivo tests,this could drive researchers to find effective treatments against the virus.
Chemoenzymatic Synthesis of Functional Sialyl LewisX Mimetics with a Heteroaromatic Core
2014
Functional mimetics of the sialyl Lewis(X) tetrasaccharide were prepared by the enzymatic sialylation of a 1,3-diglycosylated indole and a glycosyl azide, which was subsequently transformed into a 1,4-diglycosylated 1,2,3-triazole, by using the trans-sialidase of Trypanosoma cruzi. These compounds inhibited the binding of E-, L-, and P-selectin-coated nanoparticles to polyacrylamide-bound sialyl-Lewis(X) -containing neighboring sulfated tyrosine residues (sTyr/sLe(X) -PAA) at low or sub-millimolar concentrations. Except for E-selectin, the mimetics showed higher activities than the natural tetrasaccharide.
Autoimmunity to the p53 protein is a feature of systemic lupus erythematosus (SLE) related to anti-DNA antibodies.
2001
The induction of anti-DNA autoantibodies in systemic lupus erythematosus (SLE) patients is problematic because mammalian DNA is poorly immunogenic at best. Here we demonstrate a chain of connected antibodies in SLE patient sera that could account for the induction of anti-DNA antibody, and possibly for some of the pathogenic features of SLE. We now report that SLE patients, in addition to anti-DNA, produce antibodies to the carboxy-terminal domain of the tumour suppressor molecule p53; this p53 domain recognizes damaged DNA. Hence, these anti-p53 antibodies could mimic damaged DNA immunologically. Indeed, SLE sera do contain anti-idiotypic antibodies to a prototypic anti-p53 antibody. Moreo…
Longitudinal analysis of Mycobacterium tuberculosis 19-kDa antigen-specific T cells in patients with pulmonary tuberculosis: association with disease…
2003
CD8(+) T cells play a central role in immune protection against infection with Mycobacterium tuberculosis. One of the target epitopes for anti-M. tuberculosis directed CD8(+) T cells is the HLA-A2-restricted 19-kDa lipoprotein peptide VLTDGNPPEV. T cell clones directed against this epitope recognized not only the nominal peptide ligand, but also a closely related peptide (VPTDPNPPEV) from the HIV envelope gp120 (HIV(env) gp120) protein characterized by IFN-gamma release. This cross-reactivity was confirmed in ex vivo in M. tuberculosis 19-kDa tetramer-sorted T cells from patients with tuberculosis and in HIVgp120 tetramer-reactive T cells sorted from HIV(+) patients. M. tuberculosis 19-kDa …
Nitric oxide increases the decay of matrix metalloproteinase 9 mRNA by inhibiting the expression of mRNA-stabilizing factor HuR.
2003
Dysregulation of extracellular matrix turnover is an important feature of many inflammatory processes. Rat renal mesangial cells express high levels of matrix metalloproteinase 9 (MMP-9) in response to inflammatory cytokines such as interleukin-1 beta. We demonstrate that NO does strongly destabilize MMP-9 mRNA, since different luciferase reporter gene constructs containing the MMP-9 3' untranslated region (UTR) displayed significant reduced luciferase activity in response to the presence of NO. Moreover, by use of an in vitro degradation assay we found that the cytoplasmic fractions of NO-treated cells contained a higher capacity to degrade MMP-9 transcripts than those obtained from contro…
Yeast Killer Toxin-Like Candidacidal Ab6 Antibodies Elicited through the Manipulation of the Idiotypic Cascade
2014
A mouse anti-anti-anti-idiotypic (Id) IgM monoclonal antibody (mAb K20, Ab4), functionally mimicking a Wyckerhamomyces anomalus (Pichia anomala) killer toxin (KT) characterized by fungicidal activity against yeasts presenting specific cell wall receptors (KTR) mainly constituted by β-1,3-glucan, was produced from animals presenting anti-KT Abs (Ab3) following immunization with a rat IgM anti-Id KT-like mAb (mAb K10, Ab2). MAb K10 was produced by immunization with a KT-neutralizing mAb (mAb KT4, Ab1) bearing the internal image of KTR. MAb K20, likewise mAb K10, proved to be fungicidal in vitro against KT-sensitive Candida albicans cells, an activity neutralized by mAb KT4, and was capable of…
Straightforward Stereoselective Access to Cyclic Peptidomimetics
2009
The preparation of cyclic dipeptide mimetics from chiral imino lactones derived from (R)-phenylglycinol is described. Key steps of the synthetic route included the fully stereoselective construction of a quaternary center, the formation of six-, seven-, or eight-membered lactams by means of an RCM cyclization, and the introduction of a new amino group within the lactam ring. The synthesis of a tripeptide mimetic is also reported.
Heat-Shock Proteins in Autoimmunity
2013
Heat shock proteins (HSPs), also known as “stress proteins,” are among the highly conserved and immunogenic proteins shared among diverse groups of microbial agents and mammals [1]. Heat and other types of stressful stimuli can increase the cellular expression of HSPs. These proteins have been categorized into different families according to their molecular mass, for example, HSP110, HSP90, HSP70, HSP60, HSP40, HSP20-30, and HSP10 [1–3]. For uniformity, guidelines for the nomenclature of various human HSP families have been proposed [4]. Under physiological conditions, the ubiquitously distributed HSPs maintain the integrity and function of other cellular proteins in stressful conditions. H…