Rapid and quantitative detection of human adenovirus DNA by real-time PCR

Rapid diagnosis of human adenovirus (HAdV) infections was achieved by PCR in the recent years. However, conventional PCR has the risk of carry-over contamination due to open handling with its products, and results are only qualitative. Therefore, a quantitative "real-time" PCR with consensus primer and probe (dual fluorescence labelled, "TaqMan") sequences for a conserved region of the hexon gene was designed and evaluated. Real-time PCR detected all 51 HAdV prototypes. Sensitivity of the assay was <or=15 copies/run and the linear range of quantitation 1.5 x 10(1) to 1.5 x 10(8) copies/run. TaqMan PCR gave identical results compared to an established conventional one-step PCR protocol in 218 (38 positive and 180 negative) of 234 clinical samples including blood, serum, eye swabs, and feces, and had divergent results in 16 samples (15 positive only in TaqMan PCR, all with low copy numbers, and one positive only in conventional PCR), indicating a higher sensitivity of TaqMan PCR. Adenovirus viremia was detected by TaqMan PCR in 4 of 27 (14.8%) paediatric and 8 of 93 (8.6%) adult stem cell transplant recipients but only in 5 of 306 healthy controls (blood donors, 1.6%). Virus loads of pediatric patients (median 1.7 x 10(5)) were significantly higher than in adult patients (median 2.3 x 10(3)) and than in controls (all samples <or=1.7 x 10(3) copies/ml). A few immunosuppressed children had very high virus loads (up to 1.1 x 10(10) copies/ml), which were associated with symptoms of disseminated disease. In conclusion, real-time PCR is a sensitive and quantitative procedure for the detection of adenovirus infections.

Adenovirus serotype 5 hexon mediates liver gene transfer

Adenoviruses are used extensively as gene transfer agents, both experimentally and clinically. However, targeting of liver cells by adenoviruses compromises their potential efficacy. In cell culture, the adenovirus serotype 5 fiber protein engages the coxsackievirus and adenovirus receptor (CAR) to bind cells. Paradoxically, following intravascular delivery, CAR is not used for liver transduction, implicating alternate pathways. Recently, we demonstrated that coagulation factor (F)X directly binds adenovirus leading to liver infection. Here, we show that FX binds to the Ad5 hexon, not fiber, via an interaction between the FX Gla domain and hypervariable regions of the hexon surface. Binding occurs in multiple human adenovirus serotypes. Liver infection by the FX-Ad5 complex is mediated through a heparin-binding exosite in the FX serine protease domain. This study reveals an unanticipated function for hexon in mediating liver gene transfer in vivo.

Adenovirus infections in patients undergoing bone-marrow transplantation

Viral infection is commonly observed after bone-marrow transplantation. We isolated adenovirus from 51 of 1051 patients undergoing marrow transplantation between 1976 and 1982. Of the 46 isolates available for typing, 13 (27.7 per cent) were of the closely related species 11, 34, or 35 (subgenus B). All 13 of the patients with these species had positive urine cultures. The species have previously been associated with the acquired immunodeficiency syndrome or with renal transplantation but are not commonly found in community surveys. Invasive infection was confirmed by biopsy or autopsy in 10 of 51 patients. Seven of the 10 had virus isolated from lung, and 4 died from pneumonia attributed to adenovirus. Two of the five patients with renal isolates had evidence of virally induced renal impairment, and both patients with liver isolates had adenovirus hepatitis. There was no common source that accounted for these adenovirus infections, and the most likely source of infection appeared to be endogenous viral reactivation. The only identifiable risk factor for the development of infection and for severe disease was the presence of moderate to severe graft versus host disease.

Adenovirus type 11 uses CD46 as a cellular receptor

The 51 human adenovirus serotypes are divided into six species (A to F). Many adenoviruses use the coxsackie-adenovirus receptor (CAR) for attachment to host cells in vitro. Species B adenoviruses do not compete with CAR-binding serotypes for binding to host cells, and it has been suggested that species B adenoviruses use a receptor other than CAR. Species B adenoviruses mainly cause disease in the respiratory tract, the eyes, and in the urinary tract. Here we demonstrate that adenovirus type 11 (Ad11; of species B) binds to Chinese hamster ovary (CHO) cells transfected with CD46 (membrane cofactor protein)-cDNA at least 10 times more strongly than to CHO cells transfected with cDNAs encoding CAR or CD55 (decay accelerating factor). Nonpermissive CHO cells were rendered permissive to Ad11 infection upon transfection with CD46-cDNA. Soluble Ad11 fiber knob but not Ad7 or Ad5 knob inhibited binding of Ad11 virions to CD46-transfected cells, and anti-CD46 antibodies inhibited both binding of and infection by Ad11. From these results we conclude that CD46 is a cellular receptor for Ad11.

Rapid typing of human adenoviruses by a general PCR combined with restriction endonuclease analysis

We have developed a system for rapid typing of adenoviruses (Ads) based on a combination of PCR and restriction endonuclease (RE) digestion (PCR-RE digestion). Degenerated consensus primers were designed, allowing amplification of DNA from all 51 human Ad prototype strains and altogether 44 different genome variants of Ad serotypes 1, 3, 4, 5, 7, 11, 19, 40, and 41. The 301-bp amplimer of 22 prototype strains representing all six subgenera and the genome variant was selected as a target for sequencing to look for subgenus and genome type variabilities. The sequences obtained were used to facilitate the selection of specific REs for discrimination purposes in a diagnostic assay by following the concept of cleavage or noncleavage of the 301-bp amplimer. On the basis of these results, a flowchart was constructed, allowing identification of subgenus B:2 and D serotypes and almost complete distinction of subgenus A, B:1, C, E, and F serotypes. Application of the PCR-RE digestion system to clinical samples allowed typing of 34 of 40 clinical samples positive for Ad. The genome type determined by this method was identical to that obtained by traditional RE typing of full-length Ad DNA. The remaining six samples were positive only after a nested PCR. Therefore, to reduce the risk of false-negative results, samples scored negative by the PCR-RE digestion system should be evaluated by the described nested PCR. Used in combination, the PCR-RE digestion method and the nested PCR provide a reliable and sensitive system that can easily be applied to all kinds of clinical samples when rapid identification of adenoviruses is needed.

Increasing incidence of adenovirus disease in bone marrow transplant recipients

Adenovirus infections in 201 bone marrow transplant (BMT) recipients over 4 years were retrospectively reviewed. Forty-two patients (20.9%) had positive adenovirus cultures after BMT. There was a higher incidence of adenovirus infections in pediatric patients than in adults (31.3% vs. 13.6%, P = .003). In addition, the time of onset of adenovirus infection after transplant was earlier in pediatric patients (mean, < 30 days) than in adults (> 90 days). Adenovirus type 35 was the most common serotype identified. One-third of adenovirus-positive patients had definite or probable adenovirus disease. Moderate to severe acute graft-versus-host disease and isolation of adenovirus from two or more sites were significant risk factors for adenovirus disease. This report documents a higher incidence of both adenovirus infection and disease than do previous studies. Adenovirus may emerge as a more frequent pathogen as more high-risk BMT transplants are done.

Prevalence and quantitation of species C adenovirus DNA in human mucosal lymphocytes

The common species C adenoviruses (serotypes Ad1, Ad2, Ad5, and Ad6) infect more than 80% of the human population early in life. Following primary infection, the virus can establish an asymptomatic persistent infection in which infectious virions are shed in feces for several years. The probable source of persistent virus is mucosa-associated lymphoid tissue, although the molecular details of persistence or latency of adenovirus are currently unknown. In this study, a sensitive real-time PCR assay was developed to quantitate species C adenovirus DNA in human tissues removed for routine tonsillectomy or adenoidectomy. Using this assay, species C DNA was detected in Ficoll-purified lymphocytes from 33 of 42 tissue specimens tested (79%). The levels varied from fewer than 10 to greater than 2 x 10(6) copies of the adenovirus genome/10(7) cells, depending on the donor. DNA from serotypes Ad1, Ad2, and Ad5 was detected, while the rarer serotype Ad6 was not. When analyzed as a function of donor age, the highest levels of adenovirus genomes were found among the youngest donors. Antibody-coated magnetic beads were used to purify lymphocytes into subpopulations and determine whether viral DNA could be enriched within any purified subpopulations. Separation of T cells (CD4/8- expressing and/or CD3-expressing cells) enriched viral DNA in each of nine donors tested. In contrast, B-cell purification (CD19-expressing cells) invariably depleted or eliminated viral DNA. Despite the frequent finding of significant quantities of adenovirus DNA in tonsil and adenoid tissues, infectious virus was rarely present, as measured by coculture with permissive cells. These findings suggest that human mucosal T lymphocytes may harbor species C adenoviruses in a quiescent, perhaps latent form.

Analysis of 15 adenovirus hexon proteins reveals the location and structure of seven hypervariable regions containing serotype-specific residues

The first full-length hexon protein DNA and deduced amino acid sequences of a subgenus D adenovirus (AV) were determined from candidate AV48 (85-0844). Comprehensive comparison of this sequence with hexon protein sequences from human subgenera A, B, C, D, F, bovine AV3, and mouse AV1 revealed seven discrete hypervariable regions (HVRs) among the 250 variable residues in loops 1 and 2. These regions differed in length between serotypes, from 2 to 38 residues, and contained > 00% of hexon serotype-specific residues among human serotypes. Alignment with the published crystal structure of AV2 established the location and structure of the type-specific regions. Five HVRs were shown to be part of linear loops on the exposed surfaces of the protein, analogous to the serotype-specific loops or "puffs" in picornavirus capsid proteins. The HVRs were supported by a common framework of conserved residues, of which 68 to 75% were hydrophobic. Unique sequences were limited to the seven HVRs, so that one or more of these regions contain the type-specific neutralization epitopes. A neutralizing AV48 hexon-specific antiserum recognized linear peptides that corresponded to six HVRs by enzyme immunoassay. Affinity-purification removal of all peptide-reactive antibodies did not significantly decrease the neutralization titer. Eluted peptide-reactive antibodies did not neutralize. Human antisera that neutralized AV48 did not recognize linear peptides. Purified trimeric native hexon inhibited neutralization, but monomeric heat-denatured hexon did not. We conclude that the AV48 neutralization epitope(s) is complex and conformational.

International epidemiology of human pre-existing adenovirus (Ad) type-5, type-6, type-26 and type-36 neutralizing antibodies: correlates of high Ad5 titers and implications for potential HIV vaccine trials

Replication-defective adenoviruses have been utilized as candidate HIV vaccine vectors. Few studies have described the international epidemiology of pre-existing immunity to adenoviruses. We enrolled 1904 participants in a cross-sectional serological survey at seven sites in Africa, Brazil, and Thailand to assess neutralizing antibodies (NA) for adenovirus types Ad5, Ad6, Ad26 and Ad36. Clinical trial samples were used to assess NA titers from the US and Europe. The proportions of participants that were negative were 14.8% (Ad5), 31.5% (Ad6); 41.2% (Ad26) and 53.6% (Ad36). Adenovirus NA titers varied by geographic location and were higher in non-US and non-European settings, especially Thailand. In multivariate logistic regression analysis, geographic setting (non-US and non-European settings) was statistically significantly associated with having higher Ad5 titers; participants from Thailand had the highest odds of having high Ad5 titers (adjusted OR=3.53, 95% CI: 2.24, 5.57). Regardless of location, titers of Ad5NA were the highest and Ad36 NA were the lowest. Coincident Ad5/6 titers were lower than either Ad5 or Ad6 titers alone. Understanding pre-existing immunity to candidate vaccine vectors may contribute to the evaluation of vaccines in international populations.

Human adenovirus-host cell interactions: comparative study with members of subgroups B and C

Host cell interactions of human adenovirus serotypes belonging to subgroups B (adenovirus type 3 [Ad3] and Ad7) and C (Ad2 and Ad5) were comparatively analyzed at three levels: (i) binding of virus particles with host cell receptors; (ii) cointernalization of macromolecules with adenovirions; and (iii) adenovirus-induced cytoskeletal alterations. The association constants with human cell receptors were found to be similar for Ad2 and Ad3 (8 x 10(9) to 9 x 10(9) M-1), and the number of receptor sites per cell ranged from 5,000 (Ad2) to 7,000 (Ad3). Affinity blottings, competition experiments, and immunofluorescence stainings suggested that the receptor sites for adenovirus were distinct for members of subgroups B and C. Adenovirions increased the permeability of cells to macromolecules. We showed that this global effect could be divided into two distinct events: (i) cointernalization of macromolecules and virions into endocytotic vesicles, a phenomenon that occurred in a serotype-independent way, and (ii) release of macromolecules into the cytoplasm upon adenovirus-induced lysis of endosomal membranes. The latter process was found to be type specific and to require unaltered and infectious virus particles of serotype 2 or 5. Perinuclear condensation of the vimentin filament network was observed at early stages of infection with Ad2 or Ad5 but not with Ad3, Ad7, and noninfectious particles of Ad2 or Ad5, obtained by heat inactivation of wild-type virions or with the H2 ts1 mutant. This phenomenon appeared to be a cytological marker for cytoplasmic transit of infectious virions within adenovirus-infected cells. It could be experimentally dissociated from vimentin proteolysis, which was found to be serotype dependent, occurring only with members of subgroup C, regardless of the infectivity of the input virus.

The human membrane cofactor CD46 is a receptor for species B adenovirus serotype 3

Many human adenovirus (Ad) serotypes use the coxsackie B virus-Ad receptor (CAR). Recently, CD46 was suggested to be a receptor of species B Ad serotype 11 (Ad11), Ad14, Ad16, Ad21, Ad35, and Ad50. Using Sindbis virus-mediated cDNA library expression, we identify here the membrane cofactor protein CD46 as a surface receptor of species B Ad3. All four major CD46 transcripts and one minor CD46 transcript expressed in nucleated human cells were isolated. Rodent BHK cells stably expressing the BC1 form of CD46 bound radiolabeled Ad3 with a dissociation constant of 0.3 nM, identical to that of CD46-positive HeLa cells expressing twice as many Ad3 binding sites. Pull-down experiments with recombinant Ad3 fibers and a soluble form of the CD46 extracellular domain linked to the Fc portion of human immunoglobulin G (CD46ex-Fc) indicated direct interactions of the Ad3 fiber knob with CD46ex-Fc but not CARex-Fc (Fc-linked extracellular domain of CAR). Ad3 colocalized with cell surface CD46 in both rodent and human cells at the light and electron microscopy levels. Anti-CD46 antibodies and CD46ex-Fc inhibited Ad3 binding to CD46-expressing BHK cells more than 10-fold and to human cells 2-fold. In CD46-expressing BHK cells, wild-type Ad3 and a chimeric Ad consisting of the Ad5 capsid and the Ad3 fiber elicited dose-dependent cytopathic effects and transgene expression, albeit less efficiently than in human cells. Together, our results show that all of the major splice forms of CD46 are predominant and functional binding sites of Ad3 on CD46-expressing rodent and human cells but may not be the sole receptor of species B Ads on human cells. These results have implications for understanding viral pathogenesis and therapeutic gene delivery.

Species-specific identification of human adenoviruses by a multiplex PCR assay

A multiplex PCR assay was developed by using primers to the fiber gene that could differentiate human adenovirus (Ad) species A through F in a single amplification reaction. The assay correctly identified the species of all 49 recognized Ad prototype strains as well as 180 geographically and temporally diverse Ad field isolates. Ad serotype 6 (Ad6) (species C), Ad16 (species B), Ad31 (species A), and Ad40 and Ad41 (species F) could also be distinguished by amplicon size within each respective species. In comparison, a previously described Ad species-specific multiplex PCR assay that used primers to the Ad hexon gene gave equivocal results with several serotypes of species B, whereas our multiplex assay amplified all species B serotypes equally well. Our multiplex PCR assay will permit rapid, accurate, and cost-effective classification of Ad isolates.

Human adenovirus-36 is associated with increased body weight and paradoxical reduction of serum lipids

BACKGROUND

Human adenovirus-36 (Ad-36) increases adiposity and paradoxically lowers serum cholesterol and triglycerides in chickens, mice, and non-human primates. The role of Ad-36 in human obesity is unknown.

OBJECTIVES

To determine the prevalence of Ad-36 antibodies in obese and nonobese humans. To evaluate the association of Ad-36 antibodies with body mass index (BMI) and serum lipids.

DESIGN

Cohort study. Volunteers from obesity treatment programs, communities, and a research study.

SUBJECTS

Obese and nonobese volunteers at the University of Wisconsin, Madison, WI, and the Bowen Center, Naples, Florida. Obese and thin volunteer research subjects and 89 twin pairs at Columbia University, New York.

INTERVENTIONS

Study 1: 502 subjects; serum neutralization assay for antibodies to Ad-2, Ad-31, Ad-36, and Ad-37; serum cholesterol and triglycerides assays. Study 2: BMI and %body fat in 28 twin pairs discordant for Ad-36 antibodies.

MAIN OUTCOME MEASURES

Presence of antibodies to adenoviruses, BMI, serum cholesterol and triglycerides levels.

RESULTS

Significant (P < 0.001) association of obesity and positive Ad-36 antibody status, independent of age, sex, and collection site. Ad-36 antibodies in 30% of obese, 11% of nonobese. Lower serum cholesterol and triglycerides (P < 0.003) in Ad-36 antibody-positive vs -negative subjects. Twin pairs: antibody-positive twins had higher BMIs (24.5+/-5.2 vs 23.1+/-4.5 kg/m2, P < 0.03) and %body fat (29.6+/-9.5% vs 27.5+/-9.9%, P < 0.04). No association of Ad-2, Ad-31, or Ad-37 antibodies with BMI or serum lipids.

CONCLUSIONS

Ad-36 is associated with increased body weight and lower serum lipids in humans. Prospective studies are indicated to determine if Ad-36 plays a role in the etiology of human obesity.

Adenoviruses from human immunodeficiency virus-infected individuals, including two strains that represent new candidate serotypes Ad50 and Ad51 of species B1 and D, respectively

Adenovirus (Ad) isolates from a large number of human immunodeficiency virus (HIV)-infected individuals were compared serologically and genetically with Ad isolates from immunocompetent patients. Between 1982 and 1994, stool and urine samples from 137 subjects with AIDS hospitalized in The Netherlands yielded 143 Ad strains. Forty additional Ad strains were obtained from 35 HIV-positive patients in Manchester, United Kingdom, in 1992 and 1993. Of these 183 HIV-associated Ad strains, 84% belonged to species D and 3% belonged to species C. These strains were compared with 2,301 Ad strains collected during general diagnostic examinations in The Netherlands from 1973 to 1992. Of the latter strains, 5% belonged to species D and 49% belonged to species C. Two of the Ads isolated from fecal specimens of AIDS patients represent new serotypes: candidate Ad serotype 50 (prototype strain, Wan) of subspecies B1 and candidate Ad serotype 51 (prototype strain, Bom) of species D. The DNA restriction enzyme patterns of strains Wan and Bom differed from the patterns of all established prototypes.

Quantitative real-time PCR assays for detection of human adenoviruses and identification of serotypes 40 and 41

A quantitative real-time TaqMan PCR assay for detection of human adenoviruses (HAdV) was developed using broadly reactive consensus primers and a TaqMan probe targeting a conserved region of the hexon gene. The TaqMan assay correctly identified 56 representative adenovirus prototype strains and field isolates from all six adenovirus species (A to F). Based on infectious units, the TaqMan assay was able to detect as few as 0.4 and 0.004 infectious units of adenovirus serotype 2 (AdV2) and AdV41, respectively, with results obtained in less than 90 min. Using genomic equivalents, the broadly reactive TaqMan assay was able to detect 5 copies of AdV40 (which had zero mismatches with the PCR primers and probe), 8 copies of AdV41, and 350 copies of AdV3 (which had the most mismatches [seven] of any adenovirus serotype tested). For specific detection and identification of F species serotypes AdV40 and AdV41, a second real-time PCR assay was developed using fluorescence resonance energy transfer (FRET) probes that target the adenovirus fiber gene. The FRET-based assay had a detection limit of 3 to 5 copies of AdV40 and AdV41 standard DNA and was able to distinguish between AdV40 and AdV41 based on melting curve analysis. Both the TaqMan and FRET PCR assays were quantitative over a wide range of virus titers. Application of these assays for detection of adenoviruses and type-specific identification of AdV40 and AdV41 will be useful for identifying these viruses in environmental and clinical samples.

Candidate adenoviruses 40 and 41: fastidious adenoviruses from human infant stool

About 200 antigenically related adenoviruses were isolated from cases of infantile diarrhoea in the Netherlands and North-West Germany. The viruses were fastidious and failed to replicate serially in human diploid fibroblasts and in primary human embryonic kidney cells. A number of strains were established in HeLa, HEp-2, Graham (293), cynomolgus monkey kidney, and Chang conjunctival cells. The viruses were mammalian adenoviruses by the usual criteria. No relationship to the 39 known human adenovirus species was found, either by neutralization tests or by haemagglutination inhibition tests. Neutralization tests showed two distinct variants, represented by strains Tak and Dugan. The variants were identical in haemagglutination inhibition tests. DNA restriction enzyme analysis showed Tak and Dugan to have considerably different genomes, indicating that these variants should be classified as different species (Wadell et al, 1983). It is proposed that the variants should be called Mastadenovirus h 40 (with reference strains Dugan and Hovi X) and Mastadenovirus h 41 (with reference strain Tak). Neutralization and haemagglutination inhibition tests demonstrated that the viruses from Glasgow and Helsinki (Hovi X) described by Johansson et al [1980] and by Kidd and Madeley [1981] belong to these two adenovirus species.

Molecular evolution of human adenoviruses

The recent emergence of highly virulent human adenoviruses (HAdVs) with new tissue tropisms underscores the need to determine their ontogeny. Here we report complete high quality genome sequences and analyses for all the previously unsequenced HAdV serotypes (n = 20) within HAdV species D. Analysis of nucleotide sequence variability for these in conjunction with another 40 HAdV prototypes, comprising all seven HAdV species, confirmed the uniquely hypervariable regions within species. The mutation rate among HAdV-Ds was low when compared to other HAdV species. Homologous recombination was identified in at least two of five examined hypervariable regions for every virus, suggesting the evolution of HAdV-Ds has been highly dependent on homologous recombination. Patterns of alternating GC and AT rich motifs correlated well with hypervariable region recombination sites across the HAdV-D genomes, suggesting foci of DNA instability lead to formulaic patterns of homologous recombination and confer agility to adenovirus evolution.

Molecular typing of human adenoviruses by PCR and sequencing of a partial region of the hexon gene

Human adenoviruses (Ads) are responsible for a substantial disease burden. Type-specific identification of Ads can help guide therapeutic and disease prevention strategies and aid epidemiological investigations. Immunotyping of Ads by serum neutralization (SN) is laborious and time consuming and depends upon type-specific antisera that are in short supply. A rapid molecular typing assay based on polymerase chain reaction (PCR) amplification and sequencing of Ad hexon gene hyper-variable regions 1-6 (HVR(1-6)) known to contain type-specific epitopes was evaluated as an alternative to SN. Deduced amino acid sequences of HVR(1-6) obtained from all 51 currently recognized Ad prototype strains were well resolved, with the exception of types 15 and 29, which were identical. Of 192 temporally and geographically diverse Ad field isolates sequenced in this study, and 111 previously published sequences, all more closely matched their predicted prototype strains. Ads were also detected and correctly identified directly from 24 clinical specimens positive by culture or antigen detection. PCR and sequencing of HVR(1-6) offers a practical alternative to SN for typing most Ads and can be readily adapted for use in laboratories with molecular capabilities.

Simultaneous detection of influenza A, B, and C viruses, respiratory syncytial virus, and adenoviruses in clinical samples by multiplex reverse transcription nested-PCR assay

The clinical presentation of infections caused by the heterogeneous group of the respiratory viruses can be very similar. Thus, the implementation of virological assays that rapidly identify the most important viruses involved is of great interest. A new multiplex reverse transcription nested-polymerase chain reaction (RT-PCR) assay that is able to detect and type different respiratory viruses simultaneously is described. Primer sets were targeted to conserved regions of nucleoprotein genes of the influenza viruses, fusion protein genes of respiratory syncytial viruses (RSV), and hexon protein genes of adenoviruses. Individual influenza A, B, and C viruses, RSV (A and B), and a generic detection of the 48 serotypes of adenoviruses were identified and differentiated by the size of the PCR products. An internal amplification control was included in the reaction mixture to exclude false-negative results due to sample inhibitors and/or extraction failure. Detection levels of 0.1 and 0.01 TCID50 of influenza A and B viruses and 1-10 molecules of cloned amplified products of influenza C virus, RSV A and B, and adenovirus serotype 1 were achieved. The specificity was checked using specimens containing other respiratory viruses and no amplified products were detected in any case. A panel of 290 respiratory specimens from the 1999-2000 and 2000-2001 seasons was used to validate the assay. Accurately amplifying RNA from influenza and RSV prototype strains and DNA from all adenovirus serotypes demonstrates the use of this method for both laboratory routine diagnosis and surveillance of all these viruses.

Treatment of adenovirus infections in patients undergoing allogeneic hematopoietic stem cell transplantation

Retrospective analysis of 303 patients who underwent allogeneic hematopoietic stem cell transplantation identified 35 (11.5%) with adenovirus infection. Among them, 22 received specific therapy. As first-line therapy, 18 were treated with intravenous ribavirin, 3 with cidofovir, and 1 with vidarabine. Moreover, 2 received donor leukocyte infusion in combination with ribavirin, and 1 received it after failing to respond to other therapies. Seven survived (31.8%; 3 of 13 who received ribavirin alone and 2 of 3 who received cidofovir). Among the 5 patients treated with combined strategies, 2 who received donor leukocyte infusions showed clearance of all symptoms. Acute graft-versus-host disease grade > or = 3 (P = .01) and a long delay between infection and treatment (P = .05) correlated with a greater risk of treatment failure. In conclusion, ribavirin and vidarabine are ineffective options, particularly for patients at who are high risk of acquiring disseminated adenovirus disease. Conversely, cidofovir or donor leukocyte infusions seem to be encouraging approaches if initiated early.

The structure of the human adenovirus 2 penton

The adenovirus penton, a noncovalent complex of the pentameric penton base and trimeric fiber proteins, comprises the vertices of the adenovirus capsid and contains all necessary components for viral attachment and internalization. The 3.3 A resolution crystal structure of human adenovirus 2 (hAd2) penton base shows that the monomer has a basal jellyroll domain and a distal irregular domain formed by two long insertions, a similar topology to the adenovirus hexon. The Arg-Gly-Asp (RGD) motif, required for interactions with cellular integrins, occurs on a flexible surface loop. The complex of penton base with bound N-terminal fiber peptide, determined at 3.5 A resolution, shows that the universal fiber motif FNPVYPY binds at the interface of adjacent penton base monomers and results in a localized structural rearrangement in the insertion domain of the penton base. These results give insight into the structure and assembly of the adenovirus capsid and will be of use for gene-therapy applications.

Cell-binding domain of adenovirus serotype 2 fiber

The adenovirus fiber appears as a long, thin projection terminated by a knob (head). The fiber consists of a trimeric protein whose head domain is thought to interact with cell receptors. The head part (amino acids 388 to 582) of adenovirus type 2 fiber was produced in a baculovirus expression system. The purified protein was shown to cross-link into trimers. It was very resistant to proteolytic attack and seemed to attain a high degree of compactness. The head domain efficiently inhibited attachment of adenovirus to receptors on the surface of HeLa cells, thereby confirming the hypothesis that the head domain interacts with viral receptors.