Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously shown that cells infected with mouse hepatitis virus (MHV) bind rabbit, mouse, and rat IgG by the Fc portion of the IgG molecule. This Fc-binding activity appeared to be mediated by the MHV S protein. S protein could also be precipitated from MHV-infected cells by a monoclonal antibody directed against the murine Fc gamma receptor (Fc gamma R). To prove definitively that the S protein mediates Fc-binding activity, we have expressed the MHV S protein utilizing recombinant vaccinia viruses. The anti-Fc gamma R monoclonal antibody, 2.4G2, precipitated recombinant S protein in cells of murine, human, and rabbit origin. Since the anti-Fc receptor monoclonal antibody does not react with human and rabbit Fc receptors these results demonstrate that the epitope recognized by this antibody is carried on the MHV S protein and is not murine in origin. Examination of various MHV isolates and escape mutants failed to identify the precise sequences in S responsible for the molecular mimicry of the murine Fc gamma R. These data are consistent with the hypothesis that a previously identified region of similarity between the S protein and the Fc gamma R mediates this activity. The Fc binding activity of S was expressed on the cell surface, since MHV-JHM-infected cells, but not uninfected cells, formed rosettes with anti-sheep red blood cell (SRBC) antibody-coated SRBC. The anti-Fc gamma R monoclonal antibody neutralized MHV-JHM and inhibited syncytium formation induced by the MHV S protein.
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PMID:MHV S peplomer protein expressed by a recombinant vaccinia virus vector exhibits IgG Fc-receptor activity. 130 71

In this study, we describe a radioimmunoassay to detect liver membrane binding antibodies. The assay was designed to exclude binding of aggregated IgG or immune complexes to Fc gamma receptors of hepatocytes. When this assay was applied to sera from 142 patients, antibodies were found in highest titer in patients with autoimmune chronic active hepatitis, rarely in patients with hepatitis B virus-induced chronic active liver disease, and in 32% of patients with primary biliary cirrhosis. IgM antibodies were found in 100% of patients with acute Type A but not B or non-A, non-B hepatitis. IgA class antibodies were found in the sera of 57% of patients with alcohol-induced hepatitis. All patient groups showing significant titers of liver membrane antibodies display the lesion of piecemeal necrosis except those with alcohol-induced hepatitis. Further studies are needed to determine whether this antibody is the cause of the lesion.
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PMID:Liver membrane antibodies detected by immunoradiometric assay in acute and chronic virus-induced and autoimmune liver disease. 670 96

Molecular mimicry has been characterized as the presence of common epitopes, either linear or conformational, shared by host and microbial determinants. Such cross-reactivity may lead to an autoimmune disease. On the other hand molecular mimicry between certain viral proteins and host determinant may protect invading virus to be eliminated by immune system and may promote persistence. In this mini-review I discuss the molecular mimicry of S peplomer protein of mouse hepatitis virus, strain JHM (MHV-JHM) to the host Fc gamma receptor (Fc gamma R). MHV-JHM induces in rodents acute encephalomyelitis and surviving animals develop demyelinating disease with concomitant persistent infection. We have demonstrated that rabbit IgG, but not is F(ab')2 fragments, monoclonal rat and mouse IgG and the rat 2.4G2 anti-Fc gamma R mab immunoprecipitated natural and recombinant S peplomer protein of several strains of MHV. Furthermore, MHV-JHM infected cells formed rosettes with anti-sheep red blood cell (SRBC) - antibody coated SRBC. The 2.4G2 anti-Fc gamma R mab are able to neutralize several strains of MHV, presumably by binding to S peplomer protein. Therefore, the Fc binding site of S is present on the surface of MHV-infected cells. This molecular mimicry between S peplomer protein of MHV-JHM and Fc gamma R has been extended to other members of Coronaviridae, namely bovine coronavirus and transmissible gastroenteritis virus but not to infectious bronchitis virus. The molecular mimicry of viral antigens to Fc receptors has been described also for members of Herpesviridae, namely Herpes simplex, cytomegalovirus and Varicella zoster.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Molecular mimicry between Fc receptors and viral antigens. 750 51

We have previously demonstrated molecular mimicry between the S peplomer protein of mouse hepatitis virus (MHV) and Fc gamma R (Fc gamma R). A monoclonal antibody (MAb) to mouse Fc gamma R (2.4G2 anti-Fc gamma R MAb), purified rabbit immunoglobulin, but not their F(ab')2 fragments, as well as mouse and rat IgG, immunoprecipitated (1) recombinant S peplomer protein expressed by a vaccinia virus recombinant in human, rabbit, and mouse cells, and (2) natural S peplomer protein from cells infected with several strains of MHV and MHV escaped mutants. We report here results of studies documenting molecular mimicry between Fc gamma R and S peplomer protein of viruses representing three distinct antigenic subgroups of the Coronaviridae. We have shown a molecular mimicry between the S peplomer protein of bovine corona virus (BCV) and Fc gamma R. The 2.4G2 anti-Fc gamma R MAb, rabbit IgG, but not its F(ab')2 fragments, as well as homologous bovine serum, free of anti-BCV antibodies, immunoprecipitated S peplomer protein of BCV (Mebus strain). In contrast, we did not find molecular mimicry between S peplomer protein of human corona virus (HCV-OC43) and Fc gamma R. Although the OC43 virus belongs to the same antigenic group as MHV and BCV, MAb specific for human Fc gamma RI or Fc gamma RII and purified human IgG1, IgG2, and IgG3 myeloma proteins did not immunoprecipitate the S peplomer protein from HCV-OC43-infected RD cells. In addition, we did demonstrate molecular mimicry between the S peplomer protein of porcine transmissible gastroenteritis virus (TGEV) and Fc gamma R. TGEV belongs to the second antigenic subgroup of coronaviridae.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Molecular mimicry between Fc receptor and S peplomer protein of mouse hepatitis virus, bovine corona virus, and transmissible gastroenteritis virus. 776 29

In previous studies we have demonstrated molecular mimicry between the S peplomer protein of Mouse Hepatitis Virus (MHV) and Fc gamma Receptor (Fc gamma R) of IgG. Rabbit IgG, but not its F(ab')2 fragments, monoclonal rat and mouse IgG and the rat 2.4G2 anti-mouse Fc gamma R monoclonal antibody (mab) immunoprecipitated natural and recombinant MHV S protein. On the basis of a number of criteria, MHV S peplomer protein exhibits Fc IgG binding ability. We report here a molecular mimicry between the S peplomer protein of Bovine Coronavirus (BCV) and Fc gamma R. BCV S peplomer protein which belongs to the same antigenic subgroup as MHV also binds Fc portion of rabbit IgG and is immunoprecipitated by the 2.4G2 anti-Fc gamma R mab. In contrast, Transmissible Gastroenteritis Coronavirus (TGEV) and Infectious Bronchitis Virus (IBV) S peplomer proteins which represent two distinct antigenic subgroups of Coronaviridae do not bind rabbit IgG and do not react with anti-Fc gamma R mab. However, homologous swine IgG, but not its F(ab')2 fragments, immunoprecipitated from TGEV-infected cells a polypeptide chain with molecular mass of 195 kDa, identical to that immunoprecipitated by the T36 mab anti-TGEV S peplomer protein.
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PMID:Molecular mimicry between S peplomer proteins of coronaviruses (MHV, BCV, TGEV and IBV) and Fc receptor. 820 28

Immunohistochemical analysis using monoclonal antibodies specific for cells of monocyte/macrophage lineage reveals that resident liver macrophages have a phenotype distinct from that of monocytes or activated liver macrophages. Liver macrophages consist of heterogeneous cell populations in maturation (matured 25F9-positive and immature 25F9-negative) but the ratio of two populations is constant in normal and diseased livers. The expression of CD14 is down-regulated in resident liver macrophages as compared to that in monocytes, while the expression of 25F9 is up-regulated. On the other hand, the expressions of CD14 and Fc gamma RI are up-regulated in activated liver macrophages in viral and autoimmune hepatitis. In vitro culture of monocytes in medium without cytokines induces the phenotype similar to that of resident liver macrophages. Addition of macrophage-colony stimulating factor or interferon-gamma into the culture medium induces the expression of Fc gamma RI, the phenotype of which resembles that of activated liver macrophages. These results suggest that liver macrophages consist of heterogeneous cell populations and that both phenotype and function are affected by the local milieu of cytokines.
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PMID:Activated liver macrophages in human liver diseases. 858 49