Biomedical subjects

Barney S Graham

Publications and source records attributed to Barney S Graham.

At least 37 records · Page 2Linked to original sources

PubMed2005

Pathogenesis of respiratory syncytial virus infection in the murine model.

There is a wide spectrum of illness caused by respiratory syncytial virus (RSV) infection that is caused in large part by host-related factors, such as age of the patient and degree of host immunocompetency. Although the vast majority of persons infected with RSV experience symptoms of mild upper respiratory tract infection, in some people these infections cause significant morbidity and are sometimes fatal. Although a great deal of investigation in both humans and animals has explained the timing and tropism of RSV infection and the general principles by which the immune system responds to this infection, at present we only partially understand the disparity in illness severity that can occur. This article briefly reviews the clinical sequelae of RSV infection and then focuses on the mechanisms of viral pathogenesis.

Airway Obstruction↗

PubMed2004

Prolonged production of TNF-alpha exacerbates illness during respiratory syncytial virus infection.

CD8(+) CTL are the main effector cells responsible for resolving viral infections. However, the CTL response to respiratory syncytial virus (RSV) infection in mice facilitates viral clearance at the expense of significant immunopathology. Previous reports have shown a strong correlation between the mechanism of CTL activity and the severity of RSV-induced illness. Furthermore, experiments in perforin knockout mice revealed that antiviral cytokine production temporally correlated with RSV-induced illness. In the current study, we show that TNF-alpha is the dominant mediator of RSV-associated illness, and it is also important for clearance of virus-infected cells during the early stages of infection. We also demonstrate that IFN-gamma plays a protective role in conjunction with perforin/granzyme-mediated killing. Preliminary experiments in gld mice that express nonfunctional Fas ligand (FasL) revealed that RSV-induced illness is significantly reduced in the absence of FasL-mediated killing. Antiviral cytokine production was not elevated in the absence of FasL, suggesting a possible link between FasL and antiviral cytokine activity. This work shows that multiple phenotypic subsets of CD8(+) CTLs respond to RSV infection, each with varying capacities for clearance of virus-infected cells and the induction of illness. In addition, the revelation that TNF-alpha is the principal mediator of RSV-induced illness means that administration of TNF receptor antagonists, in combination with antiviral therapy, may be an effective method to treat RSV infections.

Animals↗

PubMed2004

Breakthrough infections during phase 1 and 2 prime-boost HIV-1 vaccine trials with canarypox vectors (ALVAC) and booster dose of recombinant gp120 or gp160.

Candidate human immunodeficiency virus (HIV)-1 vaccines that elicit cytotoxic T lymphocytes may modulate HIV infection, requiring a prototype evaluation to assess participants who become infected with HIV. Of 1497 participants in canarypox HIV-1 vaccine prime-boost trials, 28 (1.9%) acquired HIV-1 infection after vaccination. Median plasma HIV-1 RNA levels (vaccinees, 4.78 log10 copies/mL; placebo recipients, 4.27 log10 copies/mL) and CD4 cell counts (vaccinees, 552 cells/mm3; placebo recipients, 657 cells/mm3) before administration of antiretroviral therapy (ART) and time to a composite end point (plasma HIV-1 RNA level >55,000 copies/mL, CD4 cell count <350 cells/mm3, or initiation of ART) did not differ significantly between vaccinees and placebo recipients (P =.4, P =.1, and P =.7, respectively). Persons who acquire HIV-1 infection while enrolled in HIV-1 vaccine trials can be successfully followed after infection, to determine whether vaccines alter the course of HIV-1 infection.

AIDS Vaccines↗

PubMed2004

Inhibition of respiratory syncytial virus by RhoA-derived peptides: implications for the development of improved antiviral agents targeting heparin-binding viruses.

The respiratory syncytial virus (RSV) fusion glycoprotein (F) can interact with the small intracellular GTPase RhoA, and peptides derived from RhoA inhibit RSV replication. These observations initially suggested that RhoA-derived peptides might inhibit RSV replication by disrupting an in vivo interaction between RSV F and RhoA. However, recent data indicate that the antiviral activity of RhoA-derived peptides is not due to competitive inhibition of an hypothesized F-RhoA interaction, but is rather a function of the peptides' intrinsic biophysical properties. We summarize here what is known about the mechanism of RSV inhibition by these peptides and give our opinion regarding the potential implications of this work with regards to RSV biology, and to the development of antiviral agents targeting RSV and other enveloped viruses.

Antiviral Agents↗

PubMed2004

Modified vaccinia Ankara: potential as an alternative smallpox vaccine.

Despite the declaration of smallpox eradication in 1980, the existence of variola stockpiles and the threat of bioterrorism demand that immunity to smallpox through vaccination be maintained. Although the currently available vaccine was used for the most successful medical intervention ever accomplished, it also is associated with side effects that are difficult to accept in a vaccine for a disease that has not been present for >25 years. Herein, we review alternative approaches to maintaining immunity to smallpox through vaccination with attenuated poxviruses, and we suggest modified vaccinia Ankara (MVA) as a leading candidate for an alternative smallpox vaccine.

Humans↗

PubMed2004

Respiratory syncytial virus in allergic lung inflammation increases Muc5ac and gob-5.

Respiratory syncytial virus (RSV) is associated with wheezing and childhood asthma. We previously reported that RSV infection prolongs methacholine-induced airway hyperresponsiveness in ovalbumin (OVA)-sensitized mice. In addition, allergically sensitized RSV-infected (OVA/RSV) mice had more abundant airway epithelial mucus production compared with OVA mice 14 days after infection, whereas there was almost no mucus in mice that were only RSV infected. We hypothesized that this increased mucus was associated with mucosal expression of Muc5ac, a mucus gene expression in airways, and gob-5, a member of the Ca(2)(+)-activated chloride channel family. By histochemical analysis, we found that there was significantly increased staining for gob-5 and Muc5ac in the airways of OVA/RSV mice compared with either OVA mice or allergically sensitized mice that were challenged with inactivated RSV, and virtually no detectable staining in the RSV group. These findings were confirmed by Western blot analysis. The increased mucus expression in the OVA/RSV group was associated with increased lung levels of interleukin-17, a factor known to stimulate airway mucin gene expression. The impact of virus infection combined with allergic inflammation on mucus production may partially explain the more severe disease and airway hyperresponsiveness associated with RSV in the setting of atopy.

Animals↗

PubMed2004

Respiratory syncytial virus and other pneumoviruses: a review of the international symposium--RSV 2003.

The Respiratory Syncytial Virus 2003 symposium took place from 8th-11th November 2003 in Stone Mountain, Georgia, and brought together more than 200 international investigators engaged in RSV research. RSV biology, pathogenesis, and clinical data, as well as RSV vaccines and antivirals, were addressed in the meeting, and this review will aim to briefly summarize and discuss the implications of new findings. The meeting also served as the inauguration of the Robert M. Chanock Award for lifetime achievement in RSV research, an award named in honor of the person who started the field of RSV research by recovering the first human RS virus from infants with severe bronchiolitis in 1956.

Animals↗

PubMed2004

Contribution of respiratory syncytial virus G antigenicity to vaccine-enhanced illness and the implications for severe disease during primary respiratory syncytial virus infection.

BACKGROUND: Immunization of BALB/c mice with vaccinia virus expressing the G glycoprotein (vvG) of respiratory syncytial virus (RSV) or with formalin-inactivated alum-precipitated RSV (FI-RSV) predisposes for severe illness, type 2 cytokine production and pulmonary eosinophilia after challenge with live RSV. This similar disease profile has led to the proposal that the presence of the G glycoprotein in the FI-RSV preparation was the immunologic basis for the vaccine-associated enhancement of disease observed in the failed clinical trials of the 1960s. However, processes of disease pathogenesis observed in FI-RSV- and vvG-immunized mice suggest that FI-RSV and vvG immunizations induce immune responses of different compositions and requirements that converge to produce similar disease outcomes upon live virus challenge. METHODS: The potential role of RSV G present in FI-RSV preparations in increasing postimmunization disease severity was explored in mice. RESULTS: The absence of RSV G or its immunodominant epitope during FI-RSV immunization does not reduce disease severity after RSV challenge. Furthermore although depletion of V beta 14+ T cells during RSV challenge modulates disease in G-primed mice, minimal impact on disease in FI-RSV-immunized mice is observed. CONCLUSION: FI-RSV vaccine-enhanced illness is not attributable to RSV G. Furthermore formulation of a safe and effective RSV vaccine must ensure RSV antigen production, processing and presentation via the endogenous pathways. Thus gene delivery by vector, by DNA or by live attenuated virus are attractive vaccine approaches.

Animals↗

PubMed2004

RhoA-derived peptide dimers share mechanistic properties with other polyanionic inhibitors of respiratory syncytial virus (RSV), including disruption of viral attachment and dependence on RSV G.

Large polyanionic molecules, such as sulfated polysaccharides (including soluble heparin and dextran sulfate), synthetic polyanionic polymers, and negatively charged proteins, have been shown to broadly inhibit several enveloped viruses. We recently reported the antiviral activity of a peptide derived from amino acids 77 to 95 of a potential binding partner of respiratory syncytial virus F protein (RSV F), the GTPase RhoA. A subsequent study with a truncated peptide (amino acids 80 to 94) revealed that optimal antiviral activity required dimerization via intermolecular disulfide bonds. We report here that the net negative charge of this peptide is also a determining factor for its antiviral activity and that it, like other polyanions, inhibits virus attachment. In a flow cytometry-based binding assay, peptide 80-94, heparin, and dextran sulfate inhibited the attachment of virus to cells at 4 degrees C at the same effective concentrations at which they prevent viral infectivity. Interestingly, time-of-addition experiments revealed that peptide 80-94 and soluble heparin were also able to inhibit the infectivity of a virus that had been prebound to cells at 4 degrees C, as had previously been shown for dextran sulfate, suggesting a potential role for postattachment effects of polyanions on RSV entry. Neutralization experiments with recombinant viruses showed that the antiviral activities of peptide 80-94 and dextran sulfate were diminished in the absence of the RSV attachment glycoprotein (G). Taken together, these data indicate that the antiviral activity of RhoA-derived peptides is functionally similar to that of other polyanions, is dependent on RSV G, and does not specifically relate to a protein-protein interaction between F and RhoA.

Amino Acid Sequence↗

PubMed2004

Respiratory syncytial virus (RSV) G glycoprotein is not necessary for vaccine-enhanced disease induced by immunization with formalin-inactivated RSV.

Following respiratory syncytial virus (RSV) challenge, mice immunized with RSV G or with formalin-inactivated RSV (FI-RSV) exhibit severe disease associated with type 2 cytokine production and pulmonary eosinophilia. This has led to the proposal that the presence of RSV G is the factor in FI-RSV that induces disease-enhancing T-cell responses. Therefore, we evaluated the role of RSV G and its immunodominant region in the induction of aberrant immune responses during FI-RSV immunization. BALB/c mice were immunized with FI preparations of wild-type (wt) RSV or recombinant RSV (rRSV) containing deletions of (i) the entire G gene, (ii) the region of the G gene encoding amino acids 187 to 197 of the immunodominant region, or (iii) the entire SH gene. After challenge, illness, RSV titers, cytokine levels, and pulmonary eosinophilia were measured. Peak RSV titers postchallenge were significantly greater in mice immunized with FI preparations of the deletion viruses than in those immunized with FI-rRSV wt, suggesting that the absence of G or SH in FI-RSV reduced its protective efficacy. Deletion of G or its epitope did not reduce illness, cytokine production, or eosinophilia relative to that in mice immunized with FI-rRSV wt. While cytokine levels and eosinophilia were similar, illness was reduced in mice immunized with SH-deleted FI-RSV. These data suggest that G-specific immune responses may be important for vaccine-induced protection and are not solely the basis for FI-RSV vaccine-enhanced illness. These data suggest that the method of RSV antigen delivery, rather than the protein composition, influences the phenotype of the induced immune responses and that RSV G should not necessarily be excluded from potential vaccine strategies.

Animals↗

PubMed2004

Vbeta14(+) T cells mediate the vaccine-enhanced disease induced by immunization with respiratory syncytial virus (RSV) G glycoprotein but not with formalin-inactivated RSV.

Mice immunized with respiratory syncytial virus (RSV) G glycoprotein or with formalin-inactivated RSV (FI-RSV) exhibit severe disease following RSV challenge. This results in type 2 cytokine production and pulmonary eosinophilia, both hallmarks of vaccine-enhanced disease. RSV G-induced T-cell responses were shown to be restricted to CD4(+) T cells expressing Vbeta14 in the T-cell receptor (TCR), and the deletion of these T cells resulted in less severe disease. We therefore examined the role of Vbeta14(+) T cells in FI-RSV-induced disease. BALB/c mice were immunized with vaccinia virus expressing secreted RSV G (vvGs) or with FI-RSV. At the time of challenge with live RSV, mice were injected with antibody to the Vbeta14 component of the TCR. vvGs-immunized mice treated with anti-Vbeta14 had reduced cytokine levels in the lung. Eosinophil recruitment to the lung was also significantly reduced. In contrast, depletion of Vbeta14(+) T cells in FI-RSV-immunized mice had little impact on cytokine production or pulmonary eosinophilia. An analysis of TCR Vbeta chain usage confirmed a bias toward Vbeta14 expression on CD4(+) T cells from vvGs-immunized mice, whereas the CD4(+) T cells in FI-RSV-immunized mice expressed a diverse array of Vbeta chains. These data show that although FI-RSV and vvGs induce responses resulting in similar immunopathology, the T-cell repertoire mediating the response is different for each immunogen and suggest that the immune responses elicited by RSV G are not the basis for FI-RSV vaccine-enhanced disease.

Animals↗

PubMed2004

Signaling through the prostaglandin I2 receptor IP protects against respiratory syncytial virus-induced illness.

The role of prostanoids in modulating respiratory syncytial virus (RSV) infection is unknown. We found that RSV infection in mice increases production of prostaglandin I(2) (PGI(2)). Mice that overexpress PGI(2) synthase selectively in bronchial epithelium are protected against RSV-induced weight loss and have decreased peak viral replication and gamma interferon levels in the lung compared to nontransgenic littermates. In contrast, mice deficient in the PGI(2) receptor IP have exacerbated RSV-induced weight loss with delayed viral clearance and increased levels of gamma interferon in the lung compared to wild-type mice. These results suggest that signaling through IP has antiviral effects while protecting against RSV-induced illness and that PGI(2) is a potential therapeutic target in the treatment of RSV.

6-Ketoprostaglandin F1 alpha↗

PubMed2004

Modified vaccinia virus Ankara immunization protects against lethal challenge with recombinant vaccinia virus expressing murine interleukin-4.

Recent events have raised concern over the use of pathogens, including variola virus, as biological weapons. Vaccination with Dryvax is associated with serious side effects and is contraindicated for many people, and the development of a safer effective smallpox vaccine is necessary. We evaluated an attenuated vaccinia virus, modified vaccinia virus Ankara (MVA), by use of a murine model to determine its efficacy against an intradermal (i.d.) or intranasal (i.n.) challenge with vaccinia virus (vSC8) or a recombinant vaccinia virus expressing murine interleukin-4 that exhibits enhanced virulence (vSC8-mIL4). After an i.d. challenge, 15 of 16 mice who were inoculated with phosphate-buffered saline developed lesions, one dose of intramuscularly administered MVA was partially protective (3 of 16 mice developed lesions), and the administration of two or three doses of MVA was completely protective (0 of 16 mice developed lesions). In unimmunized mice, an i.n. challenge with vSC8 caused a significant but self-limited illness, while vSC8-mIL4 resulted in lethal infections. Immunization with one or two doses of MVA prevented illness and reduced virus titers in mice who were challenged with either vSC8 or vSC8-mIL4. MVA induced a dose-related neutralizing antibody and vaccinia virus-specific CD8+-T-cell response. Mice immunized with MVA were fully protected from a low-dose vSC8-mIL4 challenge despite a depletion of CD4+ cells, CD8+ cells, or both T-cell subsets or an antibody deficiency. CD4+- or CD8+-T-cell depletion reduced the protection against a high-dose vSC8-mIL4 challenge, and the depletion of both T-cell subsets was associated with severe illness and higher vaccinia virus titers. Thus, MVA induces broad humoral and cellular immune responses that can independently protect against a molecularly modified lethal poxvirus challenge in mice. These data support the continued development of MVA as an alternative candidate vaccine for smallpox.

Animals↗

PubMed2004

Treatment with anti-LFA-1 delays the CD8+ cytotoxic-T-lymphocyte response and viral clearance in mice with primary respiratory syncytial virus infection.

Cytotoxic T lymphocytes (CTLs) play an important role in the immune response against respiratory syncytial virus (RSV) infection. The cell surface molecule lymphocyte function-associated antigen 1 (LFA-1) is an important contributor to CTL activation, CTL-mediated direct cell lysis, and lymphocyte migration. In an attempt to determine the role of LFA-1 during RSV infection, we treated BALB/c mice with monoclonal antibodies to LFA-1 at days -1, +1, and +4 relative to primary RSV infection. Anti-LFA-1 treatment during primary RSV infection led to reduced illness and delayed clearance of virus-infected cells. CTLs from RSV-infected mice that were treated with anti-LFA-1 exhibited diminished cytolytic activity and reduced gamma interferon production. In addition, studies with BrdU (5-bromo-2'-deoxyuridine)- and CFSE [5-(and 6)-carboxyfluorescein diacetate succinimidyl ester]-labeled lymphocytes showed that anti-LFA-1 treatment led to delayed proliferation during RSV infection. These results indicate that LFA-1 plays a critical role in the initiation of the immune response to RSV infection by facilitating CTL activation. These results may prove useful in the development of new therapies to combat RSV infection or other inflammatory diseases.

Animals↗

PubMed2003

IL-13 is sufficient for respiratory syncytial virus G glycoprotein-induced eosinophilia after respiratory syncytial virus challenge.

Although well studied in settings of helminth infection and allergen sensitization, the combined contributions of IL-4 and IL-13 and their signaling pathways in models of viral pathogenesis have not been reported. Using a murine model of respiratory syncytial virus (RSV) infection, we evaluated the contribution of IL-13, alone and in conjunction with IL-4, during immunization with recombinant vaccinia virus expressing RSV G glycoprotein (vvGs) or with formalin-inactivated RSV (FI-RSV). We showed that both IL-4 and IL-13 activity must be inhibited to modulate G-specific responses resulting in severe RSV-induced disease. Inhibition of IL-4 or IL-13 activity alone had minimal impact on disease in vvGs-immunized mice. However, treatment of IL-4-deficient mice with IL-13Ra during vvGs immunization reduced IL-5, IL-13, and eotaxin production and pulmonary eosinophilia after RSV challenge. In contrast, FI-RSV-induced immune responses were diminished when either IL-4 or IL-13 activity was blocked. After RSV challenge, these type 2 T cell responses were also diminished in vvGs-primed IL-4Ralpha-deficient mice. Our data suggest that secreted vvGs uses mechanisms requiring signaling through the IL-4Ralpha-chain by either IL-4 or IL-13 for induction of eosinophilia and is the first description of the relative contributions of IL-4, IL-13, and their receptors in viral pathogenesis.

Animals↗

PubMed2003

The complex relationship between respiratory syncytial virus and allergy in lung disease.

Epidemiologic studies suggest a strong link between severe respiratory syncytial virus (RSV)-induced bronchiolitis in infancy and allergic disease; however, the mechanisms determining this relationship are currently unknown. In this review article, we summarize data from human clinical studies that explore the association between RSV infection and allergy, some that suggest that RSV bronchiolitis requiring hospitalization leads to an increased incidence of the allergic phenotype and others that suggest that pre-existing allergy is a risk factor for severe RSV bronchiolitis. We also review the published murine models that combine RSV infection and allergic sensitization that attempt to explain the complex relationship between these two factors in regard to lung immunopathology and physiologic dysfunction.

Animals↗

PubMed2003

Antiviral activity of RhoA-derived peptides against respiratory syncytial virus is dependent on formation of peptide dimers.

A synthetic peptide containing amino acids 77 to 95 of the intracellular GTPase RhoA has previously been shown to inhibit replication of respiratory syncytial virus (RSV) in cultured cells. We show that residues 80 to 90 of RhoA are sufficient for this activity and that the cysteine residue at position 83 is critical. Further studies with an optimal peptide sequence containing amino acids 80 to 94 of RhoA revealed that the antiviral potency of the peptide is dependent on the oxidation of cysteine 83. Size-exclusion chromatography and sedimentation equilibrium studies of the peptide comprising residues 80 to 94 revealed that it is capable of forming aggregates in both reduced and oxidized states. A peptide (83A) in which the cysteine residue is replaced by an alanine does not form dimers or higher-order aggregates and did not inhibit RSV replication at any concentration tested. These data indicate that formation of peptide multimers is necessary for the antiviral activities of RhoA-derived peptides and suggest that the observed antiviral activities of these peptides may be unrelated to the biological functions of their parent molecule.

Algorithms↗

PubMed2003

Herpesvirus DNA is consistently detected in lungs of patients with idiopathic pulmonary fibrosis.

On the basis of earlier reports associating Epstein-Barr Virus (EBV) with half of the cases of idiopathic pulmonary fibrosis (IPF), we hypothesized that chronic infection with EBV or a closely related herpesvirus would be detected in all cases of IPF. We tested lung specimens from 33 IPF patients (8 patients with familial IPF and 25 patients with sporadic IPF) and 25 patients with other diseases as controls for the presence of eight herpesviruses using PCR-based techniques. One or more of four herpesviruses (cytomegalovirus [CMV], EBV, human herpesvirus 7 [HHV-7], and HHV-8) were detected in 32 of 33 (97%) subjects with IPF and in 9 of 25 (36%) controls (P < 0.0001). CMV, EBV, and HHV-8 were found more frequently in IPF patients than in controls (P < 0.05, P < 0.001, and P < 0.01 respectively). Two or more herpesviruses were detected in 19 of 33 (57%) IPF patients and in 2 of 25 (8%) controls (P < 0.001). Two or more herpesviruses and HHV-8 were found more frequently in patients with sporadic IPF than in patients with familial IPF (P < 0.05 for both comparisons), and CMV was found less frequently in patients with sporadic IPF than in patients with familial IPF (P < 0.05). Immunohistochemistry for EBV or HHV-8 antigen showed viral antigen primarily in airway epithelial cells. These data support the concept that a herpesvirus could be a source of chronic antigenic stimulation in IPF.

Adult↗