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Shrestha R, Murata-Kamiya N, Imai S, Yamamoto M, Tsukamoto T, Nomura S, Hatakeyama M. Mouse Gastric Epithelial Cells Resist CagA Delivery by the Helicobacter pylori Type IV Secretion System. Int J Mol Sci 2022; 23:ijms23052492. [PMID: 35269634 PMCID: PMC8910101 DOI: 10.3390/ijms23052492] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/16/2022] [Accepted: 02/21/2022] [Indexed: 12/17/2022] Open
Abstract
The initial step in bacterial infection is adherence of the bacterium to the target cell surface. Helicobacter pylori exploits the interaction of bacterial adhesin protein HopQ with human epithelial CEACAMs (CEACAM1, 5, and 6) to stably adhere to gastric epithelial cells, which is necessary for delivery of the H. pylori CagA oncoprotein into the epithelial cells via a type IV secretion system. In contrast to human CEACAMs, however, HopQ does not interact with Ceacam1 (mouse CEACAM1) in vitro or in CHO cells ectopically expressing Ceacam1. Since the mouse genome lacks Ceacam5 and Ceacam6, no significant HopQ–Ceacam interaction may occur in mouse gastric epithelial cells. Here, we found that the mouse stomach has a much lower expression level of Ceacam1 than the expression level of CEACAM1 in the human stomach. Consistently, mouse gastric epithelial cells resist CagA delivery by cagA-positive H. pylori, and the delivery is restored by ectopic expression of human CEACAM1 or CEACAM5 in mouse gastric epithelial cells. Thus, despite the fact that mice are routinely used for H. pylori infection studies, a low expression level of Ceacam1 in the mouse stomach together with the loss or greatly reduced interaction of HopQ with Ceacams make the mouse an inappropriate model for studying the role of H. pylori-delivered CagA in gastric pathogenesis, including the development of gastric cancer.
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Affiliation(s)
- Rejina Shrestha
- Division of Microbiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; (R.S.); (N.M.-K.); (S.I.)
| | - Naoko Murata-Kamiya
- Division of Microbiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; (R.S.); (N.M.-K.); (S.I.)
| | - Satoshi Imai
- Division of Microbiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; (R.S.); (N.M.-K.); (S.I.)
| | - Masami Yamamoto
- Division of Physiological Pathology, Department of Applied Science, School of Veterinary Nursing and Technology, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo 180-8602, Japan;
| | - Tetsuya Tsukamoto
- Department of Diagnostic Pathology, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake 470-1192, Japan;
| | - Sachiyo Nomura
- Department of Gastrointestinal Surgery, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
| | - Masanori Hatakeyama
- Division of Microbiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; (R.S.); (N.M.-K.); (S.I.)
- Correspondence: ; Tel.: +81-3-5841-3404
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Bonsignore P, Kuiper JWP, Adrian J, Goob G, Hauck CR. CEACAM3-A Prim(at)e Invention for Opsonin-Independent Phagocytosis of Bacteria. Front Immunol 2020; 10:3160. [PMID: 32117212 PMCID: PMC7026191 DOI: 10.3389/fimmu.2019.03160] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/31/2019] [Indexed: 01/15/2023] Open
Abstract
Phagocytosis is one of the key innate defense mechanisms executed by specialized cells in multicellular animals. Recent evidence suggests that a particular phagocytic receptor expressed by human polymorphonuclear granulocytes, the carcinoembryonic antigen-related cell adhesion molecule 3 (CEACAM3), is one of the fastest-evolving human proteins. In this focused review, we will try to resolve the conundrum why a conserved process such as phagocytosis is conducted by a rapidly changing receptor. Therefore, we will first summarize the biochemical and structural details of this immunoglobulin-related glycoprotein in the context of the human CEACAM family. The function of CEACAM3 for the efficient, opsonin-independent detection and phagocytosis of highly specialized, host-restricted bacteria will be further elaborated. Taking into account the decisive role of CEACAM3 in the interaction with pathogenic bacteria, we will discuss the evolutionary trajectory of the CEACAM3 gene within the primate lineage and highlight the consequences of CEACAM3 polymorphisms in human populations. From a synopsis of these studies, CEACAM3 emerges as an important component of human innate immunity and a prominent example of a dedicated receptor for professional phagocytosis.
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Affiliation(s)
- Patrizia Bonsignore
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Konstanz, Germany
| | - Johannes W P Kuiper
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Konstanz, Germany
| | - Jonas Adrian
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Konstanz, Germany
| | - Griseldis Goob
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Konstanz, Germany
| | - Christof R Hauck
- Lehrstuhl Zellbiologie, Fachbereich Biologie, Universität Konstanz, Konstanz, Germany.,Konstanz Research School Chemical Biology, Universität Konstanz, Konstanz, Germany
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Schmidt T, Brodesser A, Schnitzler N, Grüger T, Brandenburg K, Zinserling J, Zündorf J. CD66b Overexpression and Loss of C5a Receptors as Surface Markers for Staphylococcus aureus-Induced Neutrophil Dysfunction. PLoS One 2015; 10:e0132703. [PMID: 26176669 PMCID: PMC4503562 DOI: 10.1371/journal.pone.0132703] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 06/17/2015] [Indexed: 11/19/2022] Open
Abstract
Neutrophil granulocytes constitute the main component of innate immunity in the clearance of bacterial infections. However, during systemic inflammation, immunoparalysis may occur resulting in neutrophil dysfunction. This study presents a new in vitro model for analyzing the dysfunction of human peripheral blood neutrophils resulting from the interaction with Staphylococcus aureus components in whole blood. After induction of a massive complement activation by S. aureus supernatant, the neutrophils exhibit a reduced phagocytic capacity resulting in a dramatic reduction of the antibacterial activity similar to that of neutrophils isolated from septic patients. The number of phagocytozing neutrophils is drastically reduced as well as the phagocytic capacity designated by a significantly lower number of ingested microbes. This dysfunction correlates with the loss of complement component 5a receptor 1 from the neutrophil cell surface and can be further characterized by a C5a-induced CD66b overexpression. The presented in vitro model offers a new platform for preclinical testing of immunosuppressive drugs and delivers new information for the understanding of neutrophil dysfunctions under the conditions described.
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Affiliation(s)
- Thomas Schmidt
- Department of Dermatology, Philipps-Universität of Marburg, Marburg, Germany
| | - Alva Brodesser
- Federal Institute for Drugs and Medical Devices, L2 Biosafety Laboratory, Bonn, Germany
| | | | - Thomas Grüger
- Federal Institute for Drugs and Medical Devices, L2 Biosafety Laboratory, Bonn, Germany
| | - Kerstin Brandenburg
- Federal Institute for Drugs and Medical Devices, L2 Biosafety Laboratory, Bonn, Germany
| | - Jörg Zinserling
- Federal Institute for Drugs and Medical Devices, Biostatistics Unit, Bonn, Germany
| | - Josef Zündorf
- Federal Institute for Drugs and Medical Devices, L2 Biosafety Laboratory, Bonn, Germany
- * E-mail:
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Pavlopoulou A, Scorilas A. A comprehensive phylogenetic and structural analysis of the carcinoembryonic antigen (CEA) gene family. Genome Biol Evol 2014; 6:1314-26. [PMID: 24858421 PMCID: PMC4079198 DOI: 10.1093/gbe/evu103] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The carcinoembryonic antigen (CEA) gene family belongs to the immunoglobulin (Ig) superfamily and codes for a vast number of glycoproteins that differ greatly both in amino acid composition and function. The CEA family is divided into two groups, the carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) and the pregnancy-specific glycoproteins. The CEA family members are implicated in pleiotropic (patho)physiological functions including cell-cell adhesion, pregnancy, immunity, neovascularization, regulation of insulin homeostasis, and carcinogenesis. In general, the CEA-encoded proteins are composed of an extracellular region with Ig variable and constant-like domains and a cytoplasmic region containing signaling motifs. Of particular interest, the well-studied human and mouse CEA genes are arranged in clusters in a single chromosome. Taking into account this characteristic, we made an effort to reconstruct the evolutionary history of the CEA gene family. Toward this end, the publicly available genomes were searched extensively for CEA homologs. The domain organization of the retrieved protein sequences was analyzed, and, subsequently, comprehensive phylogenetic analyses of the entire length CEA homologous proteins were performed. A series of evolutionarily conserved amino acid residues, functionally important, were identified. The relative positioning of these residues on the modeled tertiary structure of novel CEA protein domains revealed that they are, also, spatially conserved. Furthermore, the chromosomal arrangement of CEA genes was examined, and it was found that the CEA genes are preserved in terms of position, transcriptional orientation, and number in all species under investigation.
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Affiliation(s)
- Athanasia Pavlopoulou
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Athens, Panepistimiopolis, Athens, Greece
| | - Andreas Scorilas
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Athens, Panepistimiopolis, Athens, Greece
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Carter AM. Evolution of Placental Function in Mammals: The Molecular Basis of Gas and Nutrient Transfer, Hormone Secretion, and Immune Responses. Physiol Rev 2012; 92:1543-76. [DOI: 10.1152/physrev.00040.2011] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Placenta has a wide range of functions. Some are supported by novel genes that have evolved following gene duplication events while others require acquisition of gene expression by the trophoblast. Although not expressed in the placenta, high-affinity fetal hemoglobins play a key role in placental gas exchange. They evolved following duplications within the beta-globin gene family with convergent evolution occurring in ruminants and primates. In primates there was also an interesting rearrangement of a cassette of genes in relation to an upstream locus control region. Substrate transfer from mother to fetus is maintained by expression of classic sugar and amino acid transporters at the trophoblast microvillous and basal membranes. In contrast, placental peptide hormones have arisen largely by gene duplication, yielding for example chorionic gonadotropins from the luteinizing hormone gene and placental lactogens from the growth hormone and prolactin genes. There has been a remarkable degree of convergent evolution with placental lactogens emerging separately in the ruminant, rodent, and primate lineages and chorionic gonadotropins evolving separately in equids and higher primates. Finally, coevolution in the primate lineage of killer immunoglobulin-like receptors and human leukocyte antigens can be linked to the deep invasion of the uterus by trophoblast that is a characteristic feature of human placentation.
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Affiliation(s)
- Anthony M. Carter
- Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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Schmidt T, Zündorf J, Grüger T, Brandenburg K, Reiners AL, Zinserling J, Schnitzler N. CD66b overexpression and homotypic aggregation of human peripheral blood neutrophils after activation by a gram-positive stimulus. J Leukoc Biol 2012; 91:791-802. [PMID: 22319104 DOI: 10.1189/jlb.0911483] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Neutrophils represent the main component of innate immunity in the clearance of bacterial infections. To pass the tissue and to localize and reach the site of infection, the peripheral blood neutrophils have to pass through a complex receptor-mediated interaction with the endothelial layer. Under pathophysiological conditions, such as severe sepsis, this process is impaired and often characterized by neutrophil aggregation. In this study, we examined the impact of three different Staphylococcus aureus strains on the activation status of human peripheral blood neutrophils by coincubation of bacterial culture supernatant with whole blood. This complex interaction of a gram-positive stimulus with blood components leads to a special neutrophil activation phenotype, which is characterized by an overexpression of the cell-surface molecule CD66b. The process is accompanied by a strong increase of homotypic aggregates and seems to be initialized by a massive activation impulse caused by the interplay of plasma components. This maximum activation of neutrophils prior to the complex and highly regulated activation required for transmigration might play a key role in the neutrophil dysfunction in gram-positive sepsis.
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Affiliation(s)
- Thomas Schmidt
- Federal Institute for Drugs and Medical Devices, L2-Biosafety Laboratory, Bonn, Germany
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Li G, Jiao H, Yan H, Wang J, Wang X, Ji M. Establishment of a human CEACAM1 transgenic mouse model for the study of gonococcal infections. J Microbiol Methods 2011; 87:350-4. [PMID: 21986029 DOI: 10.1016/j.mimet.2011.09.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 09/25/2011] [Accepted: 09/26/2011] [Indexed: 12/30/2022]
Abstract
Neisseria gonorrhoeae is the causative microorganism for the sexually transmitted disease (STD) gonorrhea and humans are its only natural host. An animal model would be a useful tool for gonorrhea research, therefore we developed the hCEACAM1 transgenic mice, using an eukaryotic expression vector, pCDPCAM1-GI. This construct was microinjected into the zygotes of C57BL/6 mice and 22 F0 generation transgenic mice were obtained. Four (lines 50, 53, 54, and 59) of the F0 generation were found to carry the transgene by PCR and sequence analysis, respectively. Western blotting and Fluorescence-Activated Cell Sorting Analysis demonstrated that hCEACAM1 was expressed on the cell membrane of various tissues in the line 53 transgenic mouse. To initiate the disease in the animal model, the F2 or F3 transgenic mice were inoculated with N. gonorrhoeae intravaginally. Compared with normal mice, N. gonorrhoeae can successfully infect and cause inflammation in the transgenic mice. These data suggested the feasibility of using hCEACAM1 transgenic mice as an animal model for gonococcal infections.
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Affiliation(s)
- Guocai Li
- Department of Pathogen Biology and Immunology, Yangzhou University School of Medicine, Yangzhou, China.
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CEACAM1 recognition by bacterial pathogens is species-specific. BMC Microbiol 2010; 10:117. [PMID: 20406467 PMCID: PMC2871271 DOI: 10.1186/1471-2180-10-117] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 04/20/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), an immunoglobulin (Ig)-related glycoprotein, serves as cellular receptor for a variety of Gram-negative bacterial pathogens associated with the human mucosa. In particular, Neisseria gonorrhoeae, N. meningitidis, Moraxella catarrhalis, and Haemophilus influenzae possess well-characterized CEACAM1-binding adhesins. CEACAM1 is typically involved in cell-cell attachment, epithelial differentiation, neovascularisation and regulation of T-cell proliferation, and is one of the few CEACAM family members with homologues in different mammalian lineages. However, it is unknown whether bacterial adhesins of human pathogens can recognize CEACAM1 orthologues from other mammals. RESULTS Sequence comparisons of the amino-terminal Ig-variable-like domain of CEACAM1 reveal that the highest sequence divergence between human, murine, canine and bovine orthologues is found in the beta-strands comprising the bacteria-binding CC'FG-face of the Ig-fold. Using GFP-tagged, soluble amino-terminal domains of CEACAM1, we demonstrate that bacterial pathogens selectively associate with human, but not other mammalian CEACAM1 orthologues. Whereas full-length human CEACAM1 can mediate internalization of Neisseria gonorrhoeae in transfected cells, murine CEACAM1 fails to support bacterial internalization, demonstrating that the sequence divergence of CEACAM1 orthologues has functional consequences with regard to bacterial recognition and cellular invasion. CONCLUSIONS Our results establish the selective interaction of several human-restricted bacterial pathogens with human CEACAM1 and suggest that co-evolution of microbial adhesins with their corresponding receptors on mammalian cells contributes to the limited host range of these highly adapted infectious agents.
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Chan C, Stanners C. Recent advances in the tumour biology of the GPI-anchored carcinoembryonic antigen family members CEACAM5 and CEACAM6. ACTA ACUST UNITED AC 2010; 14:70-3. [PMID: 17576469 PMCID: PMC1891201 DOI: 10.3747/co.2007.109] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
| | - C.P. Stanners
- Correspondence to: Clifford P. Stanners, McGill University, Department of Biochemistry, 3655 Promenade Sir William Osler, Montreal, Quebec H3G 1Y6. E-mail:
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Yoon J, Terada A, Kita H. CD66b regulates adhesion and activation of human eosinophils. THE JOURNAL OF IMMUNOLOGY 2008; 179:8454-62. [PMID: 18056392 DOI: 10.4049/jimmunol.179.12.8454] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Eosinophils and their products are likely important in the pathophysiology of allergic diseases, such as bronchial asthma, and in host immunity to parasitic organisms. However, the mechanisms for proinflammatory mediator release by eosinophils are poorly understood. CD66b (CEACAM8, CGM6, NCA-95) is a single chain, GPI-anchored, highly glycosylated protein belonging to the carcinoembryonic Ag supergene family. CD66b is an activation marker for human granulocytes; however, its biological functions are largely unknown in eosinophils. We found that CD66b is highly expressed on the surface of human peripheral blood eosinophils isolated from healthy individuals. Engagement of CD66b, but not CD66a, by mAb or a natural ligand, galectin-3, activated a Src kinase family molecule, hemopoietic cell kinase (Hck), and induced cellular adhesion, superoxide production, and degranulation of eosinophils. CD66b molecules were localized in lipid rafts, and disruption of lipid rafts or removal of the GPI anchor inhibited the adhesion and activation of eosinophils. Importantly, CD66b was constitutively and physically associated with a beta2 integrin, CD11b, and cross-linking of CD66b induced a striking clustering of CD11b molecules. Thus, CD66b molecules are involved in regulating adhesion and activation of eosinophils, possibly through their localization in lipid rafts and interaction with other cell surface molecules, such as CD11b. Binding of exogenous or endogenous carbohydrate ligands(s) to CD66b may be important in the release of proinflammatory mediators by human eosinophils.
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Affiliation(s)
- Juhan Yoon
- Department of Immunology, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Aurisicchio L, Mennuni C, Giannetti P, Calvaruso F, Nuzzo M, Cipriani B, Palombo F, Monaci P, Ciliberto G, La Monica N. Immunogenicity and safety of a DNA prime/adenovirus boost vaccine against rhesus CEA in nonhuman primates. Int J Cancer 2007; 120:2290-300. [PMID: 17304509 DOI: 10.1002/ijc.22555] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Scaling up experimental protocols from rodents to humans is often not a straightforward procedure, and this particularly applies to cancer vaccines, where vaccination technology must be especially effective to overcome a variety of immune suppressive mechanisms. DNA electroporation (DNA-EP) and adenoviral vectors (Ad) have shown high potency and therapeutic efficacy for different antigens in several pre-clinical models. To evaluate the ability of DNA-EP and Ad to break tolerance to a self-antigen in large animals, we have cloned the CEA homologue (rhCEA) from rhesus monkeys (Macaca mulatta) colon tissue samples. rhCEA is a 705 aa protein and shares 78.9% homology to human CEA protein. Immunogenicity of rhCEA expressing vectors was tested in mice and subsequently in rhesus monkeys. To further increase the immunogenic potency of these vectors, a synthetic codon optimized rhCEA cDNA (rhCEAopt) was constructed. Genetic vaccination of rhesus monkeys was effective in breaking immune tolerance to rhCEA in all immunized animals, maintaining over time the elicited immune response, and most importantly, neither autoimmunity nor other side-effects were observed upon treatment. Our data confirm the efficacy of genetic cancer vaccines in large animals such as nonhuman primates and show that development of modified expression cassettes that result in increased potency of plasmid DNA and adenovirus may have a significant impact on vaccine development against malignancies expressing tumor associated antigens in patients.
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Muenzner P, Rohde M, Kneitz S, Hauck CR. CEACAM engagement by human pathogens enhances cell adhesion and counteracts bacteria-induced detachment of epithelial cells. ACTA ACUST UNITED AC 2005; 170:825-36. [PMID: 16115956 PMCID: PMC2171332 DOI: 10.1083/jcb.200412151] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Exfoliation, which is the detachment of infected epithelial cells, is an innate defense mechanism to prevent bacterial colonization. Indeed, infection with Neisseria gonorrhoeae induced epithelial detachment from an extracellular matrix (ECM) substrate in vitro. Surprisingly, variants of N. gonorrhoeae that bind to human carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) failed to induce detachment and, instead, promoted enhanced host cell adhesion to the ECM. Microarray analysis revealed that CEACAM engagement by several human pathogens triggers expression of CD105. Blockage of CD105 expression by antisense oligonucleotides abolished infection-induced cell adhesion. The expression of full-length CD105 promoted cell adhesion to the ECM and was sufficient to prevent infection-induced detachment. The CD105-mediated increase in cell adhesion was dependent on the presence and function of integrin β1. CD105 expression did not elevate cellular integrin levels but caused a dramatic increase in the ECM-binding capacity of the cells, suggesting that CD105 affects integrin activity. The exploitation of CEACAMs to trigger CD105 expression and to counteract infection-induced cell detachment represents an intriguing adaptation of pathogens that are specialized to colonize the human mucosa.
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Affiliation(s)
- Petra Muenzner
- Zentrum für Infektionsforschung, Universität Würzburg, 97070 Würzburg, Germany
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Schmitter T, Agerer F, Peterson L, Munzner P, Hauck CR. Granulocyte CEACAM3 is a phagocytic receptor of the innate immune system that mediates recognition and elimination of human-specific pathogens. ACTA ACUST UNITED AC 2004; 199:35-46. [PMID: 14707113 PMCID: PMC1887732 DOI: 10.1084/jem.20030204] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) are used by several human pathogens to anchor themselves to or invade host cells. Interestingly, human granulocytes express a specific isoform, CEACAM3, that participates together with CEACAM1 and CEACAM6 in the recognition of CEACAM-binding microorganisms. Here we show that CEACAM3 can direct efficient, opsonin-independent phagocytosis of CEACAM-binding Neisseria, Moraxella, and Haemophilus species. CEACAM3- but not CEACAM6-mediated uptake is blocked by dominant-negative versions of the small GTPase Rac. Moreover, CEACAM3 engagement triggers membrane recruitment and increased GTP loading of Rac that are not observed upon bacterial binding to CEACAM6. Internalization and Rac stimulation are also inhibited by compromising the integrity of an immunoreceptor tyrosine-based activation motif (ITAM)–like sequence in the cytoplasmic tail of CEACAM3 or by interference with Src family protein tyrosine kinases that phosphorylate CEACAM3. In contrast to interfering with CEACAM6, blockage of CEACAM3-mediated events reduces the ability of primary human granulocytes to internalize and eliminate CEACAM-binding bacteria, indicating an important role of CEACAM3 in the control of human-specific pathogens by the innate immune system.
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Affiliation(s)
- Tim Schmitter
- Zentrum für Infektionsforschung, Universität Würzburg, Röntgenring 11, 97070 Würzburg, Germany
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Scorilas A, Chiang PM, Katsaros D, Yousef GM, Diamandis EP. Molecular characterization of a new gene, CEAL1, encoding for a carcinoembryonic antigen-like protein with a highly conserved domain of eukaryotic translation initiation factors. Gene 2003; 310:79-89. [PMID: 12801635 DOI: 10.1016/s0378-1119(03)00499-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Carcinoembryonic antigen (CEA) is a complex immunoreactive glycoprotein belonging to a large and heterogeneous group of cross-reacting proteins known as the CEA gene family, which contains 29 genes/pseudogenes. CEA is used as a valuable serum tumor marker for monitoring response to therapy in patients with various solid tumors. Through the positional cloning approach we have identified and characterized a CEA-like gene (CEAL1), a novel member of the CEA multigene family. We have characterized the complete genomic structure of CEAL1, as well as one alternative splice variant and determined its chromosomal localization. The new gene is comprised of eight exons, with seven intervening introns and it is localized to chromosome 19q13.2 between the markers D19S574 and D19S219, approximately 60 kb upstream of the BCL3 gene. The protein-coding region of the gene is formed of 903 bp, encoding for a 300-amino-acid polypeptide with a predicted molecular weight of 32.6 kDa and isoelectric point of 5.74. The CEAL1 protein contains two Immunoglobulin-like (Ig-like) transmembrane domains, which are present in most of the CEA proteins, as well as one highly conserved domain of eukaryotic translation initiation factors. The identified alternative spliced variant has one more exon of 134 bp. This splice variant is expected to encode for a truncated protein of 142 amino acids with the eIF5A domain and without Ig homology domain. CEAL1 mRNA is expressed in a variety of tissues, but highest levels are found in the prostate, uterus, fetal brain, mammary, adrenal gland, skeletal muscle, small intestine and kidney. CEAL1 is highly expressed in BT-474, BT20, T47D and, at much lower levels, in MCF7 breast cancer cell lines. The new gene is also highly expressed in the LNCaP prostate cancer cell line. The CEAL1 gene was found to be down-regulated by dexamethasone in BT-474 breast cancer cell lines. Our data suggest that this gene is overexpressed in a subset of ovarian cancers which are clinically more aggressive.
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Affiliation(s)
- Andreas Scorilas
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, 600 University Avenue, M5G 1X5, Toronto, ON, Canada.
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Billker O, Popp A, Brinkmann V, Wenig G, Schneider J, Caron E, Meyer TF. Distinct mechanisms of internalization of Neisseria gonorrhoeae by members of the CEACAM receptor family involving Rac1- and Cdc42-dependent and -independent pathways. EMBO J 2002; 21:560-71. [PMID: 11847104 PMCID: PMC125849 DOI: 10.1093/emboj/21.4.560] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2001] [Revised: 12/13/2001] [Accepted: 12/13/2001] [Indexed: 02/07/2023] Open
Abstract
Opa adhesins of pathogenic Neisseria species target four members of the human carcinoembryonic antigen-related cellular adhesion molecule (CEACAM) family. CEACAM receptors mediate opsonization-independent phagocytosis of Neisseria gonorrhoeae by human granulocytes and each receptor individually can mediate gonococcal invasion of epithelial cells. We show here that gonococcal internalization occurs by distinct mechanisms depending on the CEACAM receptor expressed. For the invasion of epithelial cell lines via CEACAM1 and CEACAM6, a pathogen-directed reorganization of the actin cytoskeleton is not required. In marked contrast, ligation of CEACAM3 triggers a dramatic but localized reorganization of the host cell surface leading to highly efficient engulfment of bacteria in a process regulated by the small GTPases Rac1 and Cdc42, but not Rho. Two tyrosine residues of a cytoplasmic immune receptor tyrosine-based activating motif of CEACAM3 are essential for the induction of phagocytic actin structures and subsequent gonococcal internalization. The granulocyte-specific CEACAM3 receptor has properties of a single chain phagocytic receptor and may thus contribute to innate immunity by the elimination of Neisseria and other CEACAM-binding pathogens that colonize human mucosal surfaces.
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Affiliation(s)
- Oliver Billker
- Max-Planck-Institut für Infektionsbiologie, Abteilung Molekulare Biologie, Schumannstrasse 21/22, D-10117 Berlin, Germany
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Abstract
Carcinoembryonic antigen (CEA) is a well known tumor marker associated with the progression of colorectal tumors. The CEA family of glycoproteins has been fully characterized and the function of some of its members is now beginning to be understood. Here, we advance the hypothesis that, rather than functioning in cell adhesion as has been suggested previously, CEA plays a role in protecting the colonic mucosa from microbial invasion. This hypothesis is based on new microscopic, molecular, phylogenetic and microbiological evidence.
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Affiliation(s)
- S Hammarström
- Dept of Immunology, Umeå University, SE-90185 Umeå, Sweden.
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