Distinct cellular level of the Ca2+-binding chaperone calreticulin (CRT) is essential for correct embryonal cardiac development and postnatal function. However, CRT is also a potential autoantigen eliciting formation of antibodies (Ab), whose role is not yet clarified. Immunization with CRT leads to cardiac injury, while overexpression of CRT in cardiomyocytes induces dilated cardiomyopathy (DCM) in animals. Hence, we analysed levels of anti-CRT Ab and calreticulin in the sera of patients with idiopatic DCM and hypertrophic cardiomyopathy (HCM). ELISA and immunoblot using human recombinant CRT and Pepscan with synthetic, overlapping decapeptides of CRT were used to detect anti-CRT Ab. Serum CRT concentration was tested by ELISA. Significantly increased levels of anti-CRT Ab of isotypes IgA (p < 0.001) and IgG (p < 0.05) were found in patients with both DCM (12/34 seropositive for IgA, 7/34 for IgG) and HCM (13/38 seropositive for IgA, 11/38 for IgG) against healthy controls (2/79 for IgA, 1/79 for IgG). Titration analysis in seropositive DCM and HCM patients documented anti-CRT Ab detected at 1/1600 dilution for IgG and 1/800 for IgA (and IgA1) and at least at 1/200 dilution for IgA2, IgG1, IgG2 and IgG3. Pepscan identified immunogenic CRT epitopes recognized by IgA and IgG Ab of these patients. Significantly increased levels of CRT relative to healthy controls were found in sera of patients with HCM (p < 0.01, 5/19). These data extend the knowledge of seroprevalence of anti-CRT Ab and CRT, and suggest possible involvement of autoimmune mechanisms directed to CRT in some forms of cardiomyopathies, which are clinically heterogeneous.

• Klíčová slova
• Anti-calreticulin antibodies, autoimmunity, calreticulin, dilated cardiomyopathy, hypertrophic cardiomyopathy,
• MeSH
• autoantigeny krev   imunologie   MeSH
• autoimunita MeSH
• autoprotilátky krev   imunologie   MeSH
• biologické markery MeSH
• dilatační kardiomyopatie krev   diagnóza   imunologie   MeSH
• dospělí MeSH
• ELISA MeSH
• hypertrofická kardiomyopatie krev   diagnóza   imunologie   MeSH
• imunoglobulin A krev   imunologie   MeSH
• imunoglobulin G krev   imunologie   MeSH
• kalretikulin krev   imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• autoantigeny MeSH
• autoprotilátky MeSH
• biologické markery MeSH
• CALR protein, human MeSH Prohlížeč
• imunoglobulin A MeSH
• imunoglobulin G MeSH
• kalretikulin MeSH

Calreticulin (CALR) is an endoplasmic reticulum (ER)-resident protein involved in a spectrum of cellular processes. In healthy cells, CALR operates as a chaperone and Ca2+ buffer to assist correct protein folding within the ER. Besides favoring the maintenance of cellular proteostasis, these cell-intrinsic CALR functions support Ca2+-dependent processes, such as adhesion and integrin signaling, and ensure normal antigen presentation on MHC Class I molecules. Moreover, cancer cells succumbing to immunogenic cell death (ICD) expose CALR on their surface, which promotes the uptake of cell corpses by professional phagocytes and ultimately supports the initiation of anticancer immunity. Thus, loss-of-function CALR mutations promote oncogenesis not only as they impair cellular homeostasis in healthy cells, but also as they compromise natural and therapy-driven immunosurveillance. However, the prognostic impact of total or membrane-exposed CALR levels appears to vary considerably with cancer type. For instance, while genetic CALR defects promote pre-neoplastic myeloproliferation, patients with myeloproliferative neoplasms bearing CALR mutations often experience improved overall survival as compared to patients bearing wild-type CALR. Here, we discuss the context-dependent impact of CALR on malignant transformation, tumor progression and response to cancer therapy.

• MeSH
• kalretikulin genetika   metabolismus   MeSH
• lidé MeSH
• mutace MeSH
• myeloproliferativní poruchy metabolismus   patologie   MeSH
• nádory metabolismus   patologie   MeSH
• prezentace antigenu MeSH
• prognóza MeSH
• signální transdukce MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• kalretikulin MeSH

Calreticulin (CALR) exposed on the surface of cancer cells succumbing to therapy delivers robust phagocytic signals that support the activation of adaptive anticancer immune responses. Recent data from our group demonstrate that spontaneous CARL exposure on leukemic blasts also supports innate anticancer immunity by natural killer (NK) cells via an indirect mechanism relying on myeloid CD11c+CD14+ cells.

• Klíčová slova
• Anticancer immunity, CCR7, CD80, IL15, MHC Class II, immunogenic cell death, type I IFN,
• MeSH
• alveolární rhabdomyosarkom * MeSH
• buňky NK metabolismus   MeSH
• kalretikulin metabolismus   MeSH
• leukemie * terapie   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kalretikulin MeSH

Monoclonal antibodies to gliadin were recently found to cross-react with epitopes on rat enterocytes. Two molecules of mol. mass 62 and 66 kDa were isolated from enterocyte lysates by affinity chromatography using antigliadin monoclonal antibodies. The N-terminal amino acid sequence of the 62-kDa protein was determined to be XXXIYFKEQFLD. This amino acid sequence corresponds to amino acid sequence of rat calreticulin. The presence of calreticulin in enterocyte lysates was further confirmed using anticalreticulin serum. Anticalreticulin serum was also used to investigate the reactivity of isolated rat calreticulin. To analyze whether gliadin and calreticulin share similar epitopes recognized by anticalreticulin antibodies, synthetic dodecapeptides derived from the amino acid sequence of alpha gliadin were used in competitive ELISA assay. Two gliadin peptides, QEQVPLVQQQQF and YQLLQELCCQHL, were found to inhibit the binding of rabbit anti-rat calreticulin sera to rat calreticulin. The significant correlation was detected between IgA anticalreticulin and antigliadin antibodies (r = 0.827; P < 0.001) in celiac patients.

• MeSH
• autoantigeny imunologie   MeSH
• celiakie imunologie   MeSH
• gliadin imunologie   MeSH
• imunoglobulin A imunologie   MeSH
• kalretikulin MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• mapování epitopu MeSH
• molekulární sekvence - údaje MeSH
• monoklonální protilátky MeSH
• proteiny vázající vápník imunologie   MeSH
• ribonukleoproteiny imunologie   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• sekvenční seřazení MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• autoantigeny MeSH
• gliadin MeSH
• imunoglobulin A MeSH
• kalretikulin MeSH
• monoklonální protilátky MeSH
• proteiny vázající vápník MeSH
• ribonukleoproteiny MeSH

Calreticulin, upon translocation to the cell surface, plays a critical role in the recognition of tumour cells and in experimentally induced cellular anti-tumour immunity. However, less is known about anti-calreticulin antibodies and their role in malignancies. Using enzyme-linked immunosorbent assay (ELISA), we found immunoglobulin (Ig)A and/or IgG anti-calreticulin antibodies in sera of approximately 63% of patients with hepatocellular carcinoma (HCC), 57% of patients with colorectal adenocarcinoma (CRA) and 47% of patients with pancreatic adenocarcinoma (PACA), while healthy controls, patients with viral hepatitis C and with chronic pancreatitis reached only 2%, 20% and 31% seropositivity, respectively. We found significantly elevated mean levels of IgA anti-calreticulin antibodies (P < 0.001) in patients with HCC (78.7 +/- 52.3 AU, mean +/- standard deviation), PACA (66.5 +/- 30.9 AU) and CRA (61.8 +/- 25.8 AU) when compared to healthy controls (41.4 +/- 19.2 AU). Significantly elevated mean levels of IgG anti-calreticulin antibodies (P < 0.001) were detected in patients with HCC (121.9 +/- 94.2 AU), gall bladder adenocarcinoma (118.4 +/- 80.0 AU) and PACA (88.7 +/- 55.6 AU) when compared to healthy controls (56.7 +/- 22.9 AU). Pepscan analysis revealed a large number of antigenic epitopes of calreticulin recognized by both IgA and IgG antibodies of patients with HCC and PACA, indicating robust systemic immune response. Moreover, significantly elevated levels of antibodies against peptide KGEWKPRQIDNP (P < 0.001) in these patients, tested by ELISA, confirmed the distinct character of antibody reactivity against calreticulin. The high occurrence and specificity of serum anti-calreticulin autoantibodies in the majority of patients with some gastrointestinal malignancies provide the evidence for their possible clinical relevance.

• MeSH
• adenokarcinom krev   imunologie   MeSH
• autoantigeny imunologie   MeSH
• autoprotilátky krev   imunologie   MeSH
• B-lymfocyty imunologie   MeSH
• chronická hepatitida C krev   imunologie   MeSH
• dospělí MeSH
• ELISA MeSH
• epitopy imunologie   MeSH
• hepatocelulární karcinom krev   imunologie   MeSH
• imunoglobulin A krev   imunologie   MeSH
• imunoglobulin G krev   imunologie   MeSH
• kalretikulin imunologie   MeSH
• kolorektální nádory krev   imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• nádorové proteiny imunologie   MeSH
• nádory jater krev   imunologie   MeSH
• nádory slinivky břišní krev   imunologie   MeSH
• nádory žlučníku krev   imunologie   MeSH
• pankreatitida krev   imunologie   MeSH
• protilátky nádorové krev   imunologie   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• specificita protilátek MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• autoantigeny MeSH
• autoprotilátky MeSH
• epitopy MeSH
• imunoglobulin A MeSH
• imunoglobulin G MeSH
• kalretikulin MeSH
• nádorové proteiny MeSH
• protilátky nádorové MeSH

Calreticulin is a highly conserved calcium-binding protein affecting many cellular processes inside and outside of the endoplasmic reticulum (ER). It participates in the regulation of Ca(2+) homeostasis, acts as a chaperone and modulates gene transcription, integrin-mediated cell signalling as well as cell adhesion. Here we report on the sequence characterization of a calreticulin-coding cDNA of Eisenia fetida earthworms. The neighbor-joining phylogeny tree constructed based on the deduced amino acid sequence indicates a common origin of the E. fetida calreticulin molecule and that of mollusks. A polyclonal anti-calreticulin antibody used for immunocytochemistry and immunohistochemistry localized the protein in the mesenchymal lining of the coelomic cavity and in coelomocytes of E. fetida. In situ hybridization revealed high expression of E. fetida calreticulin in various cells and tissues, namely epidermis, neurons of the ventral nerve cord, intestine, sperms, body wall muscles and some coelomocytes. Real-time PCR confirmed the strong expression of calreticulin in the nervous system, particularly in cerebral ganglia, in body wall muscles and in seminal vesicles. Moreover, a high calreticulin expression was measured in the muscular pharynx.

• MeSH
• fylogeneze MeSH
• hybridizace in situ MeSH
• imunohistochemie MeSH
• kalretikulin genetika   metabolismus   MeSH
• klonování DNA MeSH
• komplementární DNA genetika   MeSH
• molekulární sekvence - údaje MeSH
• Oligochaeta genetika   metabolismus   MeSH
• rekombinantní proteiny genetika   MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kalretikulin MeSH
• komplementární DNA MeSH
• rekombinantní proteiny MeSH

OBJECTIVE: This study aimed to determine the amniotic fluid calreticulin concentrations in women with the preterm prelabor rupture of membranes (PPROM) based on the microbial invasion of the amniotic cavity (MIAC), intraamniotic inflammation (IAI) and microbial-associated IAI. METHODS: One hundred sixty-eight women with singleton pregnancies were included in this study. Amniotic fluid samples were obtained by transabdominal amniocentesis and were assayed for calreticulin concentrations by ELISA. IAI was defined as an amniotic fluid interleukin-6 concentration > 745 pg/ml. Microbial-associated IAI was defined as the presence of both MIAC and IAI. RESULT: Women with MIAC (with MIAC: median 54.4 ng/ml, versus without MIAC: median 32.6 ng/ml; p < 0.0001), IAI (with IAI: median 66.8 ng/ml, versus without IAI: median 33.0 ng/ml; p < 0.0001) and microbial-associated IAI (with microbial-associated IAI: median 82.5 ng/ml, versus without microbial-associated IAI: median 33.7 ng/ml; p < 0.0001) had higher concentrations of calreticulin than women without these complications. An amniotic fluid calreticulin concentration of 81.4 ng/ml was found to be the best cutoff point for identifying women with microbial-associated IAI. CONCLUSIONS: The presence of microbial-associated IAI is associated with increased amniotic fluid calreticulin concentrations. Calreticulin seems to be a promising marker for the early identification of PPROM complicated by microbial-associated IAI.

• Klíčová slova
• Bacteria, chaperon, inflammation, preterm delivery,
• MeSH
• amniocentéza MeSH
• amnion mikrobiologie   MeSH
• biologické markery analýza   MeSH
• chorioamnionitida diagnóza   MeSH
• dospělí MeSH
• ELISA MeSH
• gestační stáří MeSH
• infekční komplikace v těhotenství MeSH
• interleukin-6 analýza   MeSH
• kalretikulin analýza   MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• plodová voda chemie   mikrobiologie   MeSH
• předčasný odtok plodové vody diagnóza   MeSH
• prospektivní studie MeSH
• těhotenství MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biologické markery MeSH
• interleukin-6 MeSH
• kalretikulin MeSH

The death of cancer cells can be categorized as either immunogenic (ICD) or nonimmunogenic, depending on the initiating stimulus. The immunogenic processes of immunogenic cell death are mainly mediated by damage-associated molecular patterns (DAMPs), which include surface exposure of calreticulin (CRT), secretion of adenosine triphosphate (ATP), release of non-histone chromatin protein high-mobility group box 1 (HMGB1) and the production of type I interferons (IFNs). DAMPs are recognized by various receptors that are expressed by antigen-presenting cells (APCs) and potentiate the presentation of tumor antigens to T lymphocytes. Accumulating evidence indicates that CRT exposure constitutes one of the major checkpoints, that determines the immunogenicity of cell death both in vitro and in vivo in mouse models. Moreover, recent studies have identified CRT expression on tumor cells not only as a marker of ICD and active anti-tumor immune reactions but also as a major predictor of a better prognosis in various cancers. Here, we discuss the recent information on the CRT capacity to activate anticancer immune response as well as its prognostic and predictive role for the clinical outcome in cancer patients.

• Klíčová slova
• Calreticulin, Cancer, ER stress response, Immunogenic cell death, Prognosis,
• MeSH
• adenosintrifosfát metabolismus   MeSH
• antigen prezentující buňky imunologie   MeSH
• imunita MeSH
• interferon typ I metabolismus   MeSH
• kalretikulin genetika   metabolismus   MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• nádory diagnóza   metabolismus   MeSH
• prognóza MeSH
• protein HMGB1 genetika   metabolismus   MeSH
• regulace genové exprese u nádorů MeSH
• stres endoplazmatického retikula MeSH
• T-lymfocyty imunologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• adenosintrifosfát MeSH
• interferon typ I MeSH
• kalretikulin MeSH
• protein HMGB1 MeSH

Immunogenic cell death (ICD), a functionally peculiar type of apoptosis, represents a unique way to deliver danger-associated molecular patterns (DAMPs) to the tumor microenvironment. Once emitted by dying cancer cells, DAMPs orchestrate antigen-specific immune responses by acting on both innate and adaptive components of the immune system. Accumulating preclinical and clinical evidence indicates that one of these DAMPs, calreticulin (CALR) represents a novel powerful prognostic biomarker, reflecting the activation of a clinically relevant anticancer immune response in different cancer malignancies. Therefore, the assessment of CALR emission can provide a therapeutic tool for the stratification of cancer patients and the identification of individuals that are intrinsically capable to respond to a particular treatment. Here we describe methods for the quantification of CALR exposure in the tumor microenvironment of cancer patients by flow cytometry and immunohistochemistry.

• Klíčová slova
• Calreticulin, Cancer prognosis, Flow cytometry, Immunogenic cell death, Immunohistochemistry,
• MeSH
• imunogenní buněčná smrt * MeSH
• imunohistochemie metody   MeSH
• kalretikulin analýza   imunologie   MeSH
• lidé MeSH
• nádorové biomarkery analýza   imunologie   MeSH
• nádorové mikroprostředí MeSH
• nádory imunologie   patologie   MeSH
• průtoková cytometrie metody   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• kalretikulin MeSH
• nádorové biomarkery MeSH

BACKGROUND: Sera of patients with coeliac disease, containing IgA and IgG antigliadin antibodies (AGA) and various IgA autoantibodies, react with isolated enterocytes. AGA cross react with enterocyte antigens, one of which has been identified as calreticulin. AIMS: To characterise the antigenic structures of gliadin, enterocytes, and calreticulin recognised by AGA from patients with active coeliac disease. METHODS: AGA were isolated from sera of nine patients by affinity chromatography and tested by competitive ELISA using 40 alpha-gliadin synthetic dodecapeptides (A1-F6). RESULTS: Reactivity of gliadin with all purified AGA tested was inhibited by peptide A4 at the N-terminal region; by C2, C3, and D4 at the central region; and by F3 and F4 at the C-terminal region of the gliadin molecule. AGA cross reactivity with enterocytes was inhibited by peptides A4, D1-D4, and F6 and with calreticulin by peptides A4, D3, and D4. As dominant epitopes AGA of coeliac patients recognise similar structures corresponding to peptides A4, D3, D4, and F6 present on gliadin, enterocytes, and calreticulin. Substitution of glutamine in the A4 peptide by glutamic acid caused loss of inhibitory capacity. Shortening of peptide A4 on the N-terminal by three amino acids increased its inhibitory effect. CONCLUSIONS: AGA of patients with coeliac disease react with similar structures on gliadin and potential autoantigens on enterocytes.

• MeSH
• autoantigeny imunologie   MeSH
• autoimunitní nemoci imunologie   MeSH
• celiakie imunologie   MeSH
• chromatografie afinitní MeSH
• dospělí MeSH
• ELISA MeSH
• epitopy analýza   MeSH
• gliadin chemie   imunologie   MeSH
• kalretikulin MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• peptidové fragmenty imunologie   MeSH
• potkani Wistar MeSH
• proteiny vázající vápník imunologie   MeSH
• protilátky krev   MeSH
• ribonukleoproteiny imunologie   MeSH
• střeva imunologie   MeSH
• zkřížené reakce MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• autoantigeny MeSH
• epitopy MeSH
• gliadin MeSH
• kalretikulin MeSH
• peptidové fragmenty MeSH
• proteiny vázající vápník MeSH
• protilátky MeSH
• ribonukleoproteiny MeSH