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G Campadelli-Fiume

Publications and source records attributed to G Campadelli-Fiume.

At least 19 recordsLinked to original sources
PubMed2001

Comparison of murine and human nectin1 binding to herpes simplex virus glycoprotein D (gD) reveals a weak interaction of murine nectin1 to gD and a gD-dependent pathway of entry.

The murine nectin1alpha (mNectin1alpha), a homolog of human nectin1alpha (hNectin1alpha, or PRR1, HveC), mediates the entry of herpes simplex virus (HSV) into cells. Previously, we reported that the binding of hNectin1 to HSV glycoprotein D (gD) was readily detectable, whereas the binding of mNectin1 to gD was not detectable, thus raising the question whether mNectin1 mediates a gD-dependent or a gD-independent pathway of entry. Here we report comparative binding studies of murine- and human-nectin1alpha to virions and to gD. The assays consistently showed either a very weak binding or no detectable binding of murine nectin1alpha to gD. They included (i) binding of soluble mNectin1-Fc or hNectin1-Fc to virions and competition of the binding by soluble gD(Delta290-299t) and by monoclonal antibodies to gD; (ii) pull-down experiments of wt gD from lysates of infected cells; and (iii) ELISA binding of soluble gD(Delta290-299t) to cells expressing mNectin1 or hNectin1. In contrast to the binding studies, the entry studies readily showed that entry mediated by mNectin1 was dependent on gD. Thus, a gDnull (gD-/-) mutant virus was unable to enter mNectin1-expressing cells, and entry of wild-type virus was inhibited by antibodies to gD or soluble gD at similar concentrations. We infer that gD represents a weak ligand in the interaction between mNectin1 and virions, whereas it represents a strong and the major ligand for hNectin1. Yet gD is required in HSV-1 entry mediated by mNectin1alpha. We conclude that a high-affinity binding of the receptor to gD is not a requirement in the gD-dependent pathway of HSV entry to cells.

Animals↗
PubMed2001

Novel, soluble isoform of the herpes simplex virus (HSV) receptor nectin1 (or PRR1-HIgR-HveC) modulates positively and negatively susceptibility to HSV infection.

A novel member of the nectin family, nectin1gamma, was molecularly cloned. The cDNA has the same ectodomain as nectin1alpha and nectin1beta, the two known transmembrane isoforms that serve as receptors for herpes simplex virus (HSV) entry into human cell lines (nectin1alpha and nectin1beta, also called PRR1-HveC and HIgR, respectively). The 1.4-kb transcript, which originated by alternative splicing, is expressed in human cell lines, and appears to have a narrow distribution in human tissues. The sequence does not have a hydrophobic anchoring region, and the protein is secreted in the culture medium of cells transfected with the cDNA. Nectin1gamma, purified from culture medium, can compete with membrane-bound nectin1beta and reduce HSV infectivity. The expression of nectin1gamma cDNA in cells resistant to HSV infection and lacking HSV receptors enables HSV to enter the cell, which implies that it is present at the cell surface. Thus, nectin1gamma has the potential both to mediate and to reduce HSV entry into cells.

Amino Acid Sequence↗
PubMed2000

Human nectin3/PRR3: a novel member of the PVR/PRR/nectin family that interacts with afadin.

We have isolated nectin3/PRR3, the fourth human member of the nectin/PRR family, also described as the alpha herpes virus receptor family. Nectin/PRR members are adhesion molecules expressed at intercellular junctions. Nectin3/PRR3 is a transmembrane protein, whose extracellular region contains three Ig-like domains (V, C and C) and shares approximately 30% identity with the other members. It is mainly expressed in testis and placental tissues. SDS-PAGE analyses demonstrate that nectin3/PRR3 has a molecular weight of 83kDa. Nectin1/PRR1L and nectin2/PRR2S and L were found to be specifically expressed at the intercellular junctions. This localization is in part due to the interaction of the C-terminal part of these receptors (ended by the consensus sequence A/EXYV) and the PDZ domain of afadin. In this report we demonstrate that the nectin3/PRR3 receptor carries the A/EXYV consensus sequence and interacts in vivo with both long and short isoforms of afadin. These results suggest that the human nectin3/PRR3 is a new afadin-associated molecule.

Amino Acid Sequence↗
PubMed2000

The murine homolog of human Nectin1delta serves as a species nonspecific mediator for entry of human and animal alpha herpesviruses in a pathway independent of a detectable binding to gD.

The full-length cDNA of the murine homolog of human nectin1delta (mNectin1delta), also known as human poliovirus receptor related 1 (PRR1) or herpesvirus entry mediator C, was cloned and showed a >90% identity with its human counterpart. mNectin1delta is expressed in some murine cell lines, exemplified by NIH 3T3 and L cells, and in murine tissues. It mediates entry of an extended range of herpes simplex virus (HSV) strains, porcine pseudorabies virus (PrV), and bovine herpesvirus 1. A soluble form of the mediator blocked infectivity in mNectin1delta and human nectin1delta (hNectin1delta)-expressing cells, suggesting a physical interaction of the mediator with virions. The higher concentrations of soluble mNectin1 required to block infectivity relative to soluble hNectin1 suggest that the target of the two molecules is not identical. Entry of HSV, but not PrV, was blocked by soluble mNectin1delta in NIH 3T3 and L cells. Two features were unexpected. First, soluble mNectin1delta failed to physically interact with HSV glycoprotein D (gD) at a detectable level, although it interacted physically with virions. Second, coexpression of mNectin1delta and HSV gD did not restrict HSV or PrV infection, whereas coexpression of hNectin and gD did restrict infection, suggesting that mNectin1delta fails to be sequestered by HSV gD. We conclude that mNectin1delta serves as a species-nonspecific mediator for entry of the human and animal alphaherpesviruses. This activity, at least for HSV, is independent of a detectable binding to gD.

3T3 Cells↗
PubMed2000

Glycoprotein D or J delivered in trans blocks apoptosis in SK-N-SH cells induced by a herpes simplex virus 1 mutant lacking intact genes expressing both glycoproteins.

We have made two stocks of a herpes simplex virus 1 mutant lacking intact U(S)5 and U(S)6 open reading frames encoding glycoproteins J (gJ) and D (gD), respectively. The stock designated gD(-/+), made in cells carrying U(S)6 and expressing gD, was capable of productively infecting cells, whereas the stock designated gD(-/-), made in cells lacking viral DNA sequences, was known to attach but not initiate infection. We report the following. (i) Both stocks of virus induced apoptosis in SK-N-SH cells. Thus, annexin V binding to cell surfaces was detected as early as 8 h after infection. (ii) U(S)5 or U(S)6 cloned into the baculovirus under the human cytomegalovirus immediate-early promoter was expressed in SK-N-SH cells and blocked apoptosis in cells infected with either gD(-/+) or gD(-/-) virus, whereas glycoprotein B, infected cell protein 22, or the wild-type baculovirus did not block apoptosis. (iii) In SK-N-SH cells, internalized, partially degraded virus particles were detected at 30 min after exposure to gD(-/-) virus but not at later intervals. (iv) Concurrent infection of cells with baculoviruses did not alter the failure of gD(-/-) virus from expressing its genes or, conversely, the expression of viral genes by gD(-/+) virus. These results underscore the capacity of herpes simplex virus to initiate the apoptotic cascade in the absence of de novo protein synthesis and indicate that both gD and gJ independently, and most likely at different stages in the reproductive cycle, play a key role in blocking the apoptotic cascade leading to cell death.

Animals↗
PubMed2000

Nectin2alpha (PRR2alpha or HveB) and nectin2delta are low-efficiency mediators for entry of herpes simplex virus mutants carrying the Leu25Pro substitution in glycoprotein D.

The receptors for entry of herpes simplex viruses 1 and 2 (HSV-1 and -2), widely expressed in human cell lines, are members of a subset of the immunoglobulin superfamily exemplified by herpesvirus entry mediator C (HveC) and the herpesvirus immunoglobulin-like receptor (HIgR). This report focuses on two members of this subset, herpesvirus entry mediator B (HveB), recently designated nectin2/PRR2alpha, and its splice variant isoform, nectin2/PRR2delta. Nectin2alpha and -delta share the ectodomain but differ in the transmembrane and cytoplasmic regions. HveB was reported to enable entry of HSV-1 carrying mutations in glycoprotein D (gD) and of HSV-2, but not of wild-type (wt) HSV-1. We report that (i) both nectin2alpha and -delta served as receptors for the entry of HSV-1 mutant viruses HSV-1(U10) and -(U21) and AP7(r) that carry the Leu25Pro substitution in gD but not for HSV-1 mutants U30 and R5000 that carry the Ser140 or Ala185 substitution in gD. All of these mutants were able to overcome the block to entry mediated by expression of wt gD. (ii) Infection of cells expressing nectin2alpha or -delta required exposure to multiplicities of infection about 100-fold higher than those required to infect cells expressing HveC or HIgR. (iii) gD from HSV-1(U21) bound in vitro soluble forms of nectin2. The association was weaker than that to the soluble form of HveC/HIgR. Binding of wt HSV-1 gD to soluble nectin2 was not detectable. (iv) A major region of nectin2 functional in virus entry mapped to the V domain, located at the N terminus.

Amino Acid Substitution↗
PubMed2000

Cell-to-cell spread of wild-type herpes simplex virus type 1, but not of syncytial strains, is mediated by the immunoglobulin-like receptors that mediate virion entry, nectin1 (PRR1/HveC/HIgR) and nectin2 (PRR2/HveB).

The immunoglobulin-like receptors that mediate entry of herpes simplex virus type 1 (HSV-1) into human cells were found to mediate the direct cell-to-cell spread of wild-type virus. The receptors here designated Nectin1alpha and -delta and Nectin2alpha were originally designated HIgR, PRR1/HveC, and PRR2alpha/HveB, respectively. We report the following. (i) Wild-type HSV-1 spreads from cell to cell in J cells expressing nectin1alpha or nectin1delta but not in parental J cells that are devoid of entry receptors. A monoclonal antibody to nectin1, which blocks entry, also blocked cell-to-cell spread in nectin1-expressing J cells. Moreover, wild-type virus did not spread from a receptor-positive to a receptor-negative cell. (ii) The antibody to nectin1 blocked transmission of wild-type virus in a number of human cell lines, with varying efficiencies, suggesting that nectin1 is the principal mediator of wild-type virus spread in a variety of human cell lines. (iii) Nectin1 did not mediate cell fusion induced by the syncytial strains HSV-1(MP) and HFEM-syn. (iv) Nectin2alpha could serve as a receptor for spread of a mutant virus carrying the L25P substitution in glycoprotein D, but not of wild-type virus, in agreement with its ability to mediate entry of the mutant but not of wild-type virus.

Antibodies, Monoclonal↗
PubMed1999

Pityriasis rosea is not associated with human herpesvirus 7.

OBJECTIVE: To examine the proposed association between pityriasis rosea and human herpesvirus 7 (HHV-7). DESIGN: A retrospective cross-sectional survey. SETTING: University medical center in Switzerland. PATIENTS: Thirteen patients with pityriasis rosea and 14 persons with normal skin (control subjects). MAIN OUTCOME MEASURES: Detection of HHV-7-specific DNA sequences and antigen (85-kd phosphoprotein [pp85]) by nested polymerase chain reaction and immunohistochemical analysis, respectively. RESULTS: Human herpesvirus 7 DNA sequences and expression of the HHV-7-specific immunodominant pp85 antigen were found in 1 (8%) of 13 lesional skin biopsy specimens of pityriasis rosea. The prevalence of HHV-7 DNA sequences and antigens is even slightly lower in lesional skin of patients with pityriasis rosea than in clinically and morphologically normal skin of 14 control persons, in 2 of whom (14%) HHV-7 DNA sequences and antigens could be detected. CONCLUSION: The low detection rate of HHV-7 DNA sequences and antigens argues strongly against a causative role for HHV-7 in the pathogenesis of pityriasis rosea.

Adolescent↗
PubMed1999

Development of recombinant diagnostic reagents based on pp85(U14) and p86(U11) proteins to detect the human immune response to human herpesvirus 7 infection.

Human antibodies raised in response to human herpesvirus 7 (HHV-7) infection are directed predominantly to one or more HHV-7-infected cell proteins with apparent molecular masses of about 85 to 89 kDa. The genes that encode these proteins are unknown. However, several HHH-7 genes that possibly encode proteins in this molecular mass range have been identified. Thus, the proteins encoded by open reading frame U14 (85 kDa) and U11 (86 kDa) were expressed as recombinant proteins in bacteria. Of 13 human serum specimens that recognized the 85- to 89-kDa protein(s) of HHV-7-infected cells by immunoblotting, 12 were also reactive with recombinant pp85(U14) and 8 were reactive with p86(U11). It is concluded that (i) the HHV-7 immunodominant protein is pp85(U14) and (ii) the lack of posttranslational modifications in procaryotically expressed pp85 does not adversely affect the reactivity of human sera. Monoclonal antibody (MAb) 5E1 is an HHV-7-specific MAb directed to pp85(U14). Here, the HHV-7-specific epitope in pp85(U14) was finely mapped to the C' terminal region between amino acid residues 484 and 502. However, as indicated by the low level of reactivity of human sera with the HHV-7-specific epitope recognized by MAb 5E1, human sera recognize additional epitopes of pp85(U14) that are required for their full reactivity.

Adult↗
PubMed1999

Trafficking to the plasma membrane of the seven-transmembrane protein encoded by human herpesvirus 6 U51 gene involves a cell-specific function present in T lymphocytes.

The sequence of human herpesvirus 6 (HHV-6) U51 open reading frame predicts a protein of 301 amino acid residues with seven transmembrane domains. To identify and characterize U51, we derived antipeptide polyclonal antibodies and developed a transient expression assay. We ascertained that U51 was synthesized in cord blood mononuclear cells infected with either variant A- or variant B-HHV-6 and was transported to the surface of productively infected cells. When synthesized in transient expression systems, U51 intracellular trafficking was regulated in a cell-type-dependent fashion. In human monolayer HEK-293 and 143tk- cells, U51 accumulated predominantly in the endoplasmic reticulum and failed to be transported to the cell surface. In contrast, in T-lymphocytic cell lines J-Jhan, Molt-3, and Jurkat, U51 was successfully transported to the plasma membrane. We infer that transport of U51 to the cell surface requires a cell-specific function present in activated T lymphocytes and T-cell lines.

Animals↗
PubMed1998

The V domain of herpesvirus Ig-like receptor (HIgR) contains a major functional region in herpes simplex virus-1 entry into cells and interacts physically with the viral glycoprotein D.

The herpesvirus entry mediator C (HveC), previously known as poliovirus receptor-related protein 1 (PRR1), and the herpesvirus Ig-like receptor (HIgR) are the bona fide receptors employed by herpes simplex virus-1 and -2 (HSV-1 and -2) for entry into the human cell lines most frequently used in HSV studies. They share an identical ectodomain made of one V and two C2 domains and differ in transmembrane and cytoplasmic regions. Expression of their mRNA in the human nervous system suggests possible usage of these receptors in humans in the path of neuron infection by HSV. Glycoprotein D (gD) is the virion component that mediates HSV-1 entry into cells by interaction with cellular receptors. We report on the identification of the V domain of HIgR/PRR1 as a major functional region in HSV-1 entry by several approaches. First, the epitope recognized by mAb R1. 302 to HIgR/PRR1, capable of inhibiting infection, was mapped to the V domain. Second, a soluble form of HIgR/PRR1 consisting of the single V domain competed with cell-bound full-length receptor and blocked virion infectivity. Third, the V domain was sufficient to mediate HSV entry, as an engineered form of PRR1 in which the two C2 domains were deleted and the V domain was retained and fused to its transmembrane and cytoplasmic regions was still able to confer susceptibility, although at reduced efficiency relative to full-length receptor. Consistently, transfer of the V domain of HIgR/PRR1 to a functionally inactive structural homologue generated a chimeric receptor with virus-entry activity. Finally, the single V domain was sufficient for in vitro physical interaction with gD. The in vitro binding was specific as it was competed both by antibodies to the receptor and by a mAb to gD with potent neutralizing activity for HSV-1 infectivity.

Binding Sites↗
PubMed1998

Conservation of the architecture of the Golgi apparatus related to a differential organization of microtubules in polykaryocytes induced by syn- mutants of herpes simplex virus 1.

Infection of Vero and HEp-2 but not of 143TK- cells with herpes simplex virus 1 results in fragmentation and dispersal of the Golgi apparatus. Concurrently, in all three infected cell lines the microtubular network is disrupted, suggesting that the disruption of microtubules is essential but not sufficient to induce the fragmentation of the Golgi apparatus. We now report the following: (i) In polykaryocytes formed in Vero cells infected with HSV-1 syn- mutant viruses, intact Golgi stacks were readily detected by electron microscopy. These aggregated in the center of large polykaryocytes. (ii) The distribution of viral glycoprotein D, examined in both fixed and nonfixed cells, appeared to match the distribution of the Golgi stacks, suggesting that the aggregated Golgi stacks funnel viral glycoproteins and viral particles to a limited region of the plasma membrane of the polykaryocytes rather than directing exocytic flow in a more dispersed fashion as seen in syn+ virus-infected cells exhibiting fragmented and dispersed Golgi. (iii) In most polykaryocytes, the microtubules formed parallel bundles extending along the axis of recruitment of new cells. (iv) Fragmentation of the microtubules at the periphery of the cell near the plasma membrane was observed in untreated or cycloheximide-treated cells 2 h after infection with syn- virus HSV-1(MP) or syn+ HSV-1(mP) but not in mock-infected cells. These observations suggest that peripheral depolymerization is initiated at the time of infection and that a factor which determines the syn- or syn+ phenotype is whether the microtubular network regenerates concomitant with cell fusion or reorganizes to form a collapsed network surrounding nuclei of syn+ infected cells.

Animals↗
PubMed1998

Persistence of human herpesvirus 7 in normal tissues detected by expression of a structural antigen.

Human herpesvirus 7 (HHV-7) infection in histologically normal human tissues was investigated by immunohistochemical detection of the 85-kDa tegument phosphoprotein (pp85) encoded by the U14 gene. So far, two cell types were recognized as sites of HHV-7 infection in vivo: CD4+ T lymphocytes, believed to be the site of latent infection, and epithelial cells of salivary glands, the site of productive infection and viral shedding. Unexpectedly, cells expressing the HHV-7 structural antigen were detectable in lungs, skin, and mammary glands. Morphologically and phenotypically, they were distinct from lymphocytes. Liver, kidney, and tonsils were positive, although the number of HHV-7-positive cells was low. Large intestine, spleen, and brain were negative. Different from the current notion of the state of HHV-7 in humans, the results show that a variety of tissues harbor cells at a late stage of infection and suggest that HHV-7 causes a persistent rather than a true latent infection.

Antigens, Viral↗
PubMed1998

The ectodomain of a novel member of the immunoglobulin subfamily related to the poliovirus receptor has the attributes of a bona fide receptor for herpes simplex virus types 1 and 2 in human cells.

We report on the functional cloning of a hitherto unknown member of the immunoglobulin (Ig) superfamily selected for its ability to confer susceptibility to herpes simplex virus (HSV) infection on a highly resistant cell line (J1.1-2 cells), derived by exposure of BHKtk- cells to a recombinant HSV-1 expressing tumor necrosis factor alpha (TNF-alpha). The sequence of herpesvirus Ig-like receptor (HIgR) predicts a transmembrane protein with an ectodomain consisting of three cysteine-bracketed domains, one V-like and two C-like. HIgR shares its ectodomain with and appears to be an alternative splice variant of the previously described protein PRR-1 (poliovirus receptor-related protein). Both HIgR and PRR-1 conferred on J1.1-2 cells susceptibility to HSV-1, HSV-2, and bovine herpesvirus 1. The viral ligand of HIgR and PRR-1 is glycoprotein D, a constituent of the virion envelope long known to mediate viral entry into cells through interaction with cellular receptor molecules. Recently, PRR-1, renamed HveC (herpesvirus entry mediator C), and the related PRR-2, renamed HveB, were reported to mediate the entry of HSV-1, HSV-2, and bovine herpesvirus 1, and the homologous poliovirus receptor was reported to mediate the entry of pseudorabies virus (R. J. Geraghty, C. Krummenacher, G. H. Cohen, R. J. Eisenberg, and P. G. Spear, Science 280:1618-1620, 1998; M. S. Warner, R. J. Geraghty, W. M. Martinez, R. I. Montgomery, J. C. Whitbeck, R. Xu, R. J. Eisenberg, G. H. Cohen, and P. G. Spear, Virology 246:179-189, 1998). Here we further show that HIgR or PRR-1 proteins detected by using a monoclonal antibody to PRR-1 are widely distributed among human cell lines susceptible to HSV infection and commonly used for HSV studies. The monoclonal antibody neutralized virion infectivity in cells transfected with HIgR or PRR-1 cDNA, as well as in the human cell lines, indicating a direct interaction of virions with the receptor molecule, and preliminarily mapping this function to the ectodomain of HIgR and PRR-1. Northern blot analysis showed that HIgR or PRR-1 mRNAs were expressed in human tissues, with the highest expression being detected in nervous system samples. HIgR adds a novel member to the cluster of Ig superfamily members able to mediate the entry of alphaherpesviruses into cells. The wide distribution of HIgR or PRR-1 proteins among human cell lines susceptible to HSV infection, coupled with the neutralizing activity of the antibody in the same cells, provides direct demonstration of the actual use of this cluster of molecules as HSV-1 and HSV-2 entry receptors in human cell lines. The high level of expression in samples from nervous system makes the use of these proteins in human tissues very likely. This cluster of molecules may therefore be considered to constitute bona fide receptors for HSV-1 and HSV-2.

Amino Acid Sequence↗
PubMed1998

UL27.5 is a novel gamma2 gene antisense to the herpes simplex virus 1 gene encoding glycoprotein B.

An antibody made against the herpes simplex virus 1 US5 gene predicted to encode glycoprotein J was found to react strongly with two proteins, one with an apparent Mr of 23,000 and mapping in the S component and one with a herpes simplex virus protein with an apparent Mr of 43,000. The antibody also reacted with herpes simplex virus type 2 proteins forming several bands with apparent Mrs ranging from 43,000 to 50,000. Mapping studies based on intertypic recombinants, analyses of deletion mutants, and ultimately, reaction of the antibody with a chimeric protein expressed by in-frame fusion of the glutathione S-transferase gene to an open reading frame antisense to the gene encoding glycoprotein B led to the definitive identification of the new open reading frame, designated UL27.5. Sequence analyses indicate the conservation of a short amino acid sequence common to US5 and UL27.5. The coding sequence of the herpes simplex virus UL27.5 open reading frame is strongly homologous to the sequence encoding the carboxyl terminus of the herpes simplex virus 2 UL27.5 sequence. However, both open reading frames could encode proteins predicted to be significantly larger than the mature UL27.5 proteins accumulating in the infected cells, indicating that these are either processed posttranslationally or synthesized from alternate, nonmethionine-initiating codons. The UL27.5 gene expression is blocked by phosphonoacetate, indicating that it is a gamma2 gene. The product accumulated predominantly in the cytoplasm. UL27.5 is the third open reading frame found to map totally antisense to another gene and suggests that additional genes mapping antisense to known genes may exist.

Amino Acid Sequence↗