PubMed Health⌕ Search

Biomedical subjects

R S Fujinami

Publications and source records attributed to R S Fujinami.

At least 37 records · Page 2Linked to original sources
PubMed1998

Nitric oxide synthase inhibitor, aminoguanidine, reduces inflammation and demyelination produced by Theiler's virus infection.

This study evaluated effects of the inducible nitric oxide synthase (iNOS) inhibitor, aminoguanidine (AG), on the neuropathology and clinical disease produced by Theiler's murine encephalomyelitis virus (TMEV) DA strain infection. Treatment with AG was started on day 7, 14, 28 or 66 post-inoculation and continued for a minimum of 21 days. Inflammation, demyelination and axonal necrosis were scored in a blinded fashion on spinal cord sections from each mouse. Reduction in inflammation, demyelination and axonal necrosis was observed in mice treated with AG. Apoptosis within the spinal cord parenchyma and perivascular cuffs was significantly decreased. AG treatment resulted in delayed onset of clinical disease.

Animals↗
PubMed1998

Enhancement of experimental allergic encephalomyelitis (EAE) by DNA immunization with myelin proteolipid protein (PLP) plasmid DNA.

Relapsing-remitting experimental allergic encephalomyelitis (R-EAE) is an animal model for multiple sclerosis (MS). Many potential immunomodulatory strategies for MS have been used first in EAE to assess their effectiveness. Recently, the injection of plasmid DNA has been shown to induce potent humoral and cellular immune responses. The primary aim of our experiments reported here was to determine if vaccination with cDNAs encoding myelin proteolipid protein (PLP) could prime for a PLP-specific immune response and affect subsequent R-EAE. We constructed cDNAs encoding whole PLP (pPLP(all)) or encephalitogenic epitopes PLP(139-151) (pPLP(139-151)) and PLP(178-191) (pPLP(178-191)). Following DNA injection, we induced R-EAE in SJL/J mice using PLP(139-151) or PLP(178-191) peptides in adjuvant. All 3 plasmid constructs enhanced R-EAE induced with PLP(139-151), and injection of mice with pPLP(all) increased R-EAE induced with PLP(178-191). DNA immunization induced higher PLP peptide-specific lymphoproliferative responses than did vector alone following R-EAE induction with IgG1 or IgG2b antibody responses. These data suggest that DNA immunization of PLP can modulate immune responses, leading to enhancement of R-EAE.

Animals↗
PubMed1998

Modulation of immune system function by measles virus infection: role of soluble factor and direct infection.

Measles virus infection can result in a variety of immunologic defects. We have begun studies to determine the basis for the lack of immune responsiveness to antigen and mitogen following infection. Here we present data showing that Epstein-Barr virus-transformed B-cell lines infected with measles virus produce a soluble factor that can inhibit antigen-specific T-cell proliferation and inhibit the proliferation of uninfected B cells. The soluble factor was neither interleukin-10, transforming growth factor beta, nor alpha/beta interferon. B cells infected with measles virus or treated with the soluble factor were unable to present antigen to T cells in a manner that supported antigen-specific proliferation. This could represent one mechanism of how measles virus limits T-cell expansion. However, we found that once CD4(+) or CD8(+) T cells were activated, their cytolytic activity was intact whether infected with measles virus or treated with soluble factor. Thus, while slow to be generated these cytoxic cells could participate in viral clearance.

Antigen Presentation↗
PubMed1998

Replacement of loop II of VP1 of the DA strain with loop II of the GDVII strain of Theiler's murine encephalomyelitis virus alters neurovirulence, viral persistence, and demyelination.

Theiler's murine encephalomyelitis viruses, which are murine picornaviruses, can cause central nervous system inflammatory disease. To study the role of loop II in capsid protein VP1, two mutant viruses of strain DA in which DA loop II amino acids were replaced with strain GDVII amino acids were constructed. Infection of mice with the two mutant viruses led to dramatically different patterns of disease.

Animals↗
PubMed1997

Measles virus infection of human T cells modulates cytokine generation and IL-2 receptor alpha chain expression.

Measles virus (MV) suppresses specific functions in cells of the immune system and causes a generalized immunosuppression by mechanisms which remain undefined. It has been previously established that mitogen-induced proliferation of peripheral blood mononuclear cells (PBMC) is suppressed by infection with MV. Our current study demonstrates that MV infection inhibits antigen-specific proliferation of T lymphocytes. The inhibition of proliferation was not due to a decrease in IL-2 production. IL-2 production in cultures of infected and uninfected antigen-specific T cells was similar. In contrast, we found that expression of the IL-2R alpha subunit was decreased in mitogen-stimulated, MV-infected PBMC and antigen-stimulated, MV-infected T lymphocytes compared to stimulated but noninfected T cells. However, the expression of the IL-2R beta subunit was not altered in MV-infected T cells. We also examined the influence of MV infection on the production of the cytokines IL-4, IL-6, IL-10, and IFN-gamma by T lymphocytes. By comparing infected versus uninfected antigen-specific T cell lines, we found that MV infection of antigen-specific activated T cells caused no substantial change in generation of IFN-gamma, IL-6, or IL-10. There was a 50% reduction in IL-4 generation following MV infection. These data indicate that the immunosuppression by acute MV infection is not associated with a generalized inhibition of cytokine production. One mechanism for the suppression of proliferation following acute MV infection may be a block in the expression of the IL-2R alpha subunit by activated T cells.

CD4-Positive T-Lymphocytes↗
PubMed1997

Apoptosis in acute and chronic central nervous system disease induced by Theiler's murine encephalomyelitis virus.

Apoptosis has been observed in neural development and in various neurological diseases, including viral infection and multiple sclerosis. Theiler's murine encephalomyelitis virus is divided into two subgroups based on neurovirulence: the highly neurovirulent GDVII strain produces an acute fatal polioencephalomyelitis in mice, whereas the attenuated DA strain produces demyelination with virus persistence preceded by an acute infection. TUNEL combined with immunocytochemistry was used to detect apoptosis in the central nervous system and to characterize which cell types were involved during the acute stage in both GDVII and DA virus infection and during the chronic stage in DA virus infection. We found that during the acute stage, apoptosis was induced in neurons in both virus infections. However, the number of apoptotic neurons was much greater in GDVII virus-infected mice than in DA virus-infected mice (P < 0.01). During the chronic stage of DA virus infection, apoptotic cells were detected only in the spinal cord white matter. Some of these cells were dual labeled for fragmented DNA and carbonic anhydrase II, an oligodendrocyte marker. Our results indicate that apoptosis of neurons could be responsible for the fatal outcome in GDVII virus infection. In contrast, apoptosis of oligodendrocytes can contribute to the chronic demyelinating DA virus infection.

Acute Disease↗
PubMed1997

Enhancement of EAE and induction of autoantibodies to T-cell epitopes in mice infected with a recombinant vaccinia virus encoding myelin proteolipid protein.

SJL/J mice were infected with a recombinant vaccinia virus encoding myelin proteolipid protein (PLP) (VVplp). Antibody responses to whole PLP and to encephalitogenic peptides, p139-151, p178-191 or p104-117 were measured after vaccination and following challenge with these three PLP peptides. Competitive ELISAs showed that antibodies to p139-151 and p178-191 represented the majority of antibodies in the anti-PLP antibody response following VVplp vaccination, since the antibodies to intact PLP could be inhibited 56, 35 and 1%, respectively, by p139-151, p178-191 and p104-117. After peptide challenge, epitope specific anti-peptide antibodies were enhanced. These anti-peptide antibodies also reacted with the intact PLP molecule. Interestingly, the mean titer of anti-p139-151 antibody in p139-151 challenged mice was significantly higher than that observed for anti-p178-191 in p178-191 and for anti-p104-117 in p104-117 challenged mice. Following peptide challenge, the anti-PLP IgG response shifted from an IgG1 to an IgG2a and 2b phenotype. In these mice, both the clinical disease and histological pattern of experimental allergic encephalomyelitis (EAE) were enhanced. The enhancement was most pronounced in the pathologic scores in the p139-151 challenged group followed by p104-117 challenged mice. Thus, humoral immune responses to PLP encephalitogenic peptides can be generated with virus encoding a self central nervous system (CNS) protein.

Animals↗
PubMed1997

Antisense-mediated resistance to measles virus infection in HeLa cells.

Endogenous expression of antisense RNA in transfected cells has been explored for use in blocking cellular gene expression and for its antiviral potential. Antisense strategies were used with the goal of blocking measles virus (MV) infection. A recombinant expression plasmid was designed to produce antisense oligonucleotides targeted to the 5' end of the MV nucleocapsid protein mRNA. This construct was transfected into HeLa cells. The transfected cell line and a control cell line expressing a random RNA comprising the same nucleotides were infected with MV and assessed for viral resistance by observation of cytopathic effect (CPE); infectious virus was quantified by viral plaque assay. Both cell lines were also infected with a related paramyxovirus, mumps virus, as a specificity control. Both CPE and infectious virus were reduced by approximately 90% in the antisense-expressing line compared with that in control cells or transfectant cells expressing random RNA. There was no evidence of resistance to infection with mumps virus in any cell line.

Cytopathogenic Effect, Viral↗
PubMed1997

Hydrocephalus in mice infected with a Theiler's murine encephalomyelitis virus variant.

The etiology of hydrocephalus is never established in the majority of clinical cases, while various agents, nutritional deficiencies, and genetic factors have been shown to play a role. Viral infection has been recognized as one of the causative factors in the development of hydrocephalus. The wild-type DA strain of Theiler's murine encephalomyelitis virus (TMEV), which belongs to the family Picornaviridae, causes a chronic demyelinating disease in mice with viral persistence that resembles multiple sclerosis. We found that a DA virus variant, hydrocephalus 101 virus (H101 virus), caused hydrocephalus in mice, a condition previously never described for TMEV. To clarify the relationship between DA virus infection and hydrocephalus, we compared H101 virus and wild-type DA virus infection in mice. Using immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL), we found that during the acute phase of infection, H101 virus caused macrocephaly and meningitis with the presence of apoptosis, while parenchymal involvement was not evident. In contrast, wild-type DA virus caused an acute polioencephalomyelitis with parenchymal infection and apoptosis. During the chronic phase, H101 virus infection caused communicating hydrocephalus without viral persistence. No demyelination and little or no anti-TMEV antibodies were observed in H101 virus-infected mice. Sequence analysis revealed that H101 virus had mutations in the 5'UTR and capsid protein coding region. Characterization of this new hydrocephalus model gives insight into the possible viral involvement in human hydrocephalus cases of obscure etiology.

Animals↗
PubMed1997

Lack of correlation of Theiler's virus binding to cells with infection.

The DA strain of Theiler's murine encephalomyelitis virus (TMEV) is a picornavirus which infects the murine central nervous system (CNS). During the acute stage versus the chronic stage, different cell-types are infected. To clarify the shift seen during persistent infection, we have screened various cell lines for their ability to support TMEV infection and used virus binding assays to determine if there was a correlation between permissiveness and virus binding. Cell lines of different origins were able to support virus infection to varying degrees. Infectious center assays and viral binding assay demonstrated that permissiveness to virus infection and the ability of virus to attach to the cell surface did not always correlate.

Animals↗
PubMed1996

Virus encoding an encephalitogenic peptide protects mice from experimental allergic encephalomyelitis.

The association of viral infections with autoimmune central nervous system (CNS) diseases such as post-infectious encephalomyelitis and possibly multiple sclerosis (MS) prompted the investigation to understand how virus infection could modulate autoimmune responses. Recombinant vaccinia viruses encoding an encephalitogenic portion of myelin basic protein (MBP) were evaluated in an animal model for human demyelinating disease, experimental allergic encephalomyelitis (EAE). We have determined that mice vaccinated with recombinant viruses encoding an encephalitogenic region of MBP were protected from EAE. In vivo depletion of CD8+ T cells did not abrogate this protection, suggesting lack of regulation by this cell type. These studies demonstrate that virus infection may be a means to modulated immune responsiveness to CNS disease.

Amino Acid Sequence↗
PubMed1996

Two models for multiple sclerosis: experimental allergic encephalomyelitis and Theiler's murine encephalomyelitis virus.

In this review, we compare and contrast two popular models for multiple sclerosis (MS), Theiler's murine encephalomyelitis virus (TMEV) disease and experimental allergic encephalomyelitis (EAE). These models are used to investigate the viral and autoimmune etiology of MS, respectively. Infection with live TMEV is an essential component of TMEV demyelinating disease. TMEV-specific cellular and humoral immunity and apoptosis of infected cells eliminate virus from the gray matter of the central nervous system (CNS) during the acute phase of TMEV disease. In contrast, during the chronic phase, TMEV persistently infects glial cells and/or macrophages in the white matter. During the chronic phase, recruitment of macrophages, TMEV-specific T cells and antibody, with the induction of apoptosis are harmful to the host, leading to inflammation and demyelination. In EAE, induction of encephalitogenic CD4+ T cells is an important component for disease. After stimulation and activation, these T cells upregulate adhesion molecules and are able to enter the CNS. Th1 cytokines augment the recruitment of mononuclear cells in the CNS. Macrophages and/or glial cells secrete cytotoxic factors leading to demyelination in conjunction with B cells secreting anti-myelin antibody. Although immunopathological pathways during the course of the demyelination in TMEV infection and EAE are not always the same, oligodendroglial apoptosis is observed in both models, suggesting that their demyelinating processes share a common terminal pathway and finally lead to quite a similar clinical and pathological picture.

Animals↗
PubMed1995

Protection of SJL/J mice from demyelinating disease mediated by Theiler's murine encephalomyelitis virus.

Intracerebral infection with the DA strain of Theiler's murine encephalomyelitis virus induces a chronic demyelinating disease in SJL/J mice. Intraperitoneal inoculation with either the wild-type DA virus or an attenuated variant virus of DA, H7A6-2, results in protection from development of chronic demyelinating disease. Protective anti-viral immune responses result in reduced viral titers and decreased inflammation in the central nervous system within the first week following intracerebral challenge with virus. Development of protective immunity requires the presence of B cells and CD4+ T cells but does not require CD8+ T cells. High titers of serum anti-viral IgG and neutralizing antibodies are induced following the intraperitoneal inoculation with the DA virus or H7A6-2 virus prior to challenge. While protection could not be transferred with immune serum from DA virus-infected mice or neutralizing monoclonal antibodies, protection was correlated with increased numbers of DA virus-specific plasma cells in the central nervous system within the first week following intracerebral challenge. Protected mice also had enhanced levels of anti-DA virus IgG and neutralizing antibodies in the cerebral spinal fluid by 1 week following intracerebral challenge with DA virus. Thus, we conclude that vaccination with live virus results in protection from chronic demyelinating disease by inducing immune responses which are manifested in the central nervous system and rapidly clear infection after intracerebral challenge with DA virus.

Animals↗
PubMed1995

B-lymphocyte requirement for vaccine-mediated protection from Theiler's murine encephalomyelitis virus-induced central nervous system disease.

The role of humoral immunity in the protection of vaccinated SJL/J mice from central nervous system disease induced by the DA strain (DAV) of Theiler's murine encephalomyelitis virus was investigated in B-cell-deficient mice. Mice were depleted of B cells by treatment with a mouse monoclonal antibody specific for immunoglobulin M. DAV-vaccinated, B-cell-deficient mice failed to clear viral infection and were no longer protected from Theiler's murine encephalomyelitis virus-mediated central nervous system disease. CD4+ T cells are required in this model of protection to provide help for the development of an antiviral antibody response in the central nervous system.

Animals↗
PubMed1994

Characterization of a murine central nervous system-derived cell line: infectability and presentation of viral antigen.

The cerebral endothelial cell line, 33-Mse, was characterized for its MHC antigen expression, infectability with viruses and capacity to present antigen to immune spleen cells. The cell line had interferon-gamma inducible MHC antigen expression. Infection by Theiler's murine encephalomyelitis influenced the expression of MHC molecules on the cell surface of this line. These cells could not stimulate T splenocyte proliferation or act as targets for Theiler's murine encephalomyelitis cytolytic immune spleen cells. These cells were able to present viral antigen to vaccinia virus immune spleen cells and act as targets for cytotoxic T cells from vaccinia virus immune mice.

Animals↗
PubMed1994

Importance of amino acid 101 within capsid protein VP1 for modulation of Theiler's virus-induced disease.

We constructed a Theiler's virus mutant designated DA3304, in which the amino acid at position 101 of VP1 was changed from a threonine to an alanine. Because of this single amino acid change, DA3304 could still produce a biphasic central nervous system disease similar to that produced by the wild-type DA virus. However, DA3304 was significantly attenuated in both the acute and the chronic phases and induced smaller demyelinating lesions than the wild-type DA virus. The data are most compatible with the attenuated phenotype in DA3304 being due to the change of binding efficiency between the virus and receptor resulting from the physical alteration at the mutation site.

Animals↗
PubMed1993

Enhancement of autoimmune disease using recombinant vaccinia virus encoding myelin proteolipid protein.

Viral infections have been associated with the initiation and exacerbations often observed with autoimmune disease. Mechanisms by which viruses may play a role in the development of autoreactive immune responses include polyclonal activation of B and T cells, molecular mimicry, viral infection of immune cells, exposure of sequestered antigens, or altered host cell expression (neoantigen or altered self) in virus infected host cells. We have been studying the immune response generated to self proteins in association with viral infection. Here we evaluate the effects of viral infection on the development of an autoimmune disease of the central nervous system, experimental allergic encephalomyelitis. A vaccinia virus construct, VVplp was made containing the coding region for rat myelin proteolipid protein (PLP). Cells infected with VVplp were found to express PLP protein in vitro. Central nervous system disease was not detectable in mice vaccinated with VVplp. However, mice vaccinated with VVplp and later challenged with encephalitogenic peptides derived from PLP were found to have enhanced disease with earlier onset of symptoms when compared to mice treated with a control vaccinia virus construct. This enhancement of disease was found to peak at 10 days post challenge with the encephalitogenic PLP peptide. Clinical disease and an inflammatory response in the central nervous system was evident in mice previously vaccinated with VVplp but not in control vaccinated mice at this time. These results indicate that prior infection with a virus capable of coding for self protein can predispose the host to an accentuated autoimmune response.

Animals↗