Seroepidemiology of new AIDS-associated adenoviruses among the San Francisco Men's Health Study

First isolation of a new type of human adenovirus (genotype 79), species Human mastadenovirus B (B2) from sewage water in Japan

Human mastadenoviruses (HAdVs) are highly infectious viral pathogens that survive for prolonged periods in environmental waters. We monitored the presence of HAdVs in sewage waters between April 2014 and March 2015. A total of 27 adenoviral strains were detected in 75% (18/24 in occasion-base) of 24 wastewater collected samples. We identified the types of the strains as HAdV-C2 (n = 5), HAdV-A31 (5), HAdV-C1 (4), HAdV-B3 (4), HAdV-C5 (4), HAdV-B11 (2), P11H34F11 (2), and HAdV-D56 (1). The complete genome sequence of one P11H34F11 (strain T150125) was determined by next-generation sequencing and compared to other genome sequences of HAdV-B strains. The comparisons revealed evidence of a recombination event with breaking point in the hexon encoding region, which evidenced high similarity to HAdV-B34, while half of the rest of the genome showed similarity to HAdV-B11, including regions encoding fiber and E3 region proteins. The penton base encoding region seemed to be a recombinant product of HAdV-B14, -34; however, it was evidenced to be divergent to both as a novel type despite showing low bootstrap to support a new clade. We propose T150125 (P11H34F11) is a strain of a novel genotype, HAdV-79. These results support the usefulness of environmental surveillance approaches to monitor circulating HAdVs including novel types.

Oncolytic Adenovirus: Strategies and Insights for Vector Design and Immuno-Oncolytic Applications

Adenoviruses (Ad) are commonly used both experimentally and clinically, including oncolytic virotherapy applications. In the clinical area, efficacy is frequently hampered by the high rates of neutralizing immunity, estimated as high as 90% in some populations that promote vector clearance and limit bioavailability for tumor targeting following systemic delivery. Active tumor targeting is also hampered by the ubiquitous nature of the Ad5 receptor, hCAR, as well as the lack of highly tumor-selective targeting ligands and suitable targeting strategies. Furthermore, significant off-target interactions between the viral vector and cellular and proteinaceous components of the bloodstream have been documented that promote uptake into non-target cells and determine dose-limiting toxicities. Novel strategies are therefore needed to overcome the obstacles that prevent efficacious Ad deployment for wider clinical applications. The use of less seroprevalent Ad serotypes, non-human serotypes, capsid pseudotyping, chemical shielding and genetic masking by heterologous peptide incorporation are all potential strategies to achieve efficient vector escape from humoral immune recognition. Conversely, selective vector arming with immunostimulatory agents can be utilized to enhance their oncolytic potential by activation of cancer-specific immune responses against the malignant tissues. This review presents recent advantages and pitfalls occurring in the field of adenoviral oncolytic therapies.

A novel complex recombinant form of type 48-related human adenovirus species D isolated in Japan

Recently, new genotypes of human adenoviruses (HAdVs) have been reported and many of them have been found to be recombinant forms of different known types of HAdV species D (HAdV-D). The objective of this study was to document the evolutionary features of a novel isolate (HAdV_Chiba_E086/2012) obtained from the eye swab of a patient with conjunctivitis in Japan. Viral DNA was extracted from the isolate to sequence the whole genome by the Sanger method and aligned with available genome sequences of HAdV-Ds. The phylogenetic trees of the nucleotide sequences of the penton base, hexon, and fiber genes and the E3 region showed that HAdV_Chiba_E086/2012 is closest to HAdV genotype 65 (HAdV-GT65), HAdV-48, HAdV-GT60 and HAdV-22 at 98%, 99%, 95% and 98% identity, respectively, suggesting that this isolate is a novel recombinant form to be designated as P65H48F60. Further phylogenetic and recombination analyses of the genome alignment of the new isolate implied that nested recombination events involving HAdV-GT59, GT65, 48, GT60, 22, and some ancestral lineages or their close relatives have shaped its genome. These results showed that HAdV_Chiba_E086/2012 is the first HAdV-48-related HAdV found in Japan, which has the most complicated evolutionary history among the known HAdVs so far.

Computational analysis of adenovirus serotype 5 (HAdV-C5) from an HAdV coinfection shows genome stability after 45 years of circulation

Adenovirus coinfections present opportunities for genome recombination. Computational analysis of an HAdV-C5 field strain genome, recovered from a patient with acute respiratory disease and coinfected with HAdV-B21, shows that there was no exchange of genomic material into HAdV-C5. Comparison of this genome to the sparsely amplified prototype demonstrates a high level of sequence conservation and stability of this genome across 45 years. Further, comparison to a version of the prototype that had been passaged in laboratory settings shows stability as well. HAdV genome stability and evolution are considerations for applications as vaccines and as vectors for gene delivery. In the annotation analysis, a single sequencing error in the HAdV-C5_ARM (Adenovirus Reference Material) genome is noted and may lead to erroneous annotation and biological interpretations.

Generation of a novel replication-incompetent adenoviral vector derived from human adenovirus type 49: manufacture on PER.C6 cells, tropism and immunogenicity

Recombinant adenoviral vectors based on type 5 (rAd5) show great promise as a vaccine carrier. However, neutralizing activity against Ad5 is prevalent and high-titred among human populations, and significantly dampens Ad5-based vaccine modalities. The generation of alternative adenoviral vectors with low seroprevalence thus receives much research attention. Here, it is shown that a member from human adenovirus subgroup D, i.e. Ad49, does not cross-react with Ad5 neutralizing activity, making it a candidate serotype for vector development. Therefore, a plasmid system that allows formation of replication-incompetent adenovirus serotype 49 vaccine vectors (rAd49) was constructed and it was demonstrated that rAd49 can be successfully propagated to high titres on existing Ad5.E1-complementing cell lines such as PER.C6. Using an rAd49 vector carrying the luciferase marker gene, detailed seroprevalence studies were performed, demonstrating that rAd49 has low seroprevalence and neutralizing antibody titres worldwide. Also, we have initiated rAd49 vector receptor usage suggesting that rAd49 utilizes hCD46 as a cellular receptor. Finally, the immunogenicity of the rAd49 vector was assessed and it was shown that an rAd49.SIVGag vaccine induces strong anti-SIVGag CD8+ T-lymphocytes in naïve mice, albeit less than an rAd5.SIVGag vaccine. However, in mice with high anti-Ad5 immunity the rAd5.SIVGag vaccine was severely blunted, whereas the anti-SIVGag response was not significantly suppressed using the rAd49.SIVGag vaccine. These data demonstrate the potential of a replication deficient human group D adenoviral vector for vaccination purposes.

The impact of adenovirus infection on the immunocompromised host

Adenovirus (Ad) infections in immunocompromised hosts have increased in frequency as the number of patients with transplants of bone marrow, liver, kidney, heart and other organs increase in number and survive longer. The numbers of such patients have also increased because of the emergence of the HIV epidemic. Ad infections with the 51 different serotypes recognised to date have few pathognomonic signs and symptoms, and thus require a variety of laboratory-based procedures to confirm infection. These viruses have the ability to target various organs with relative serotype specificity and can cause diverse manifestations including serious life-threatening diseases characteristic of the organs involved. Ads have cytolytic and immunoregulatory properties. The clinical dilemma remains the prompt recognition of Ad-related disease, the differentiation of Ad infection from Ad disease and the differentiation from other causative agents. Since the armamentarium of effective antiviral agents available to treat Ads is unproven by controlled trials and the virus is often not acquired de novo, it is difficult to prevent reactivation in immunodeficient hosts or new acquisition from donor organs. Timely discontinuation of immunosuppressive agents is necessary to prevent morbid outcomes. The clinical diseases, diagnostic tests, antiviral agents and biological aspects of the Ads as pathogens in immunocompromised patients are discussed in the context of this review. Some of the newer diagnostic tests are based on the well-studied molecular biology of Ads, which also have been attenuated by selective viral DNA deletions for use as vectors in numerous gene therapy trials in humans.

Enteric viral infections as a cause of diarrhoea in the acquired immunodeficiency syndrome

BACKGROUND AND AIMS

The role of non-cytomegalovirus (CMV) enteric viral infection in causing diarrhoea in patients with human immunodeficiency virus (HIV) is poorly understood. We aimed to investigate the prevalence of these infections in acute and chronic diarrhoea.

METHODS

Stool specimens from 377 HIV-infected patients presenting with diarrhoea were studied prospectively for evidence of non-CMV enteric viral infection. Patients with diarrhoea underwent investigation for gastrointestinal pathogens, including electron microscopic examination of stool for enteric viruses. We collected data on patients in whom enteric virus was identified and examined the association of enteric virus infection with diarrhoeal symptomatology.

RESULTS

Eighty-nine (10.3%) stool specimens from 60 (15.9%) HIV+ individuals were positive for coronavirus (n = 13, 22%), rotavirus (n = 11, 18%), adenovirus (n = 30, 50%) and small round structured viruses (n = 5, 8%) or dual infection (n = 2, 3%). Thirty-four of 52 (65%) patients available for analysis had acute diarrhoea, and 18/52 (35%) had chronic diarrhoea. Twenty-three of 52 (44%) patients had a concurrent gut pathogen. After exclusion of concurrent pathogens enteric viral infections were found to be significantly associated with acute as opposed to chronic diarrhoea (P = 0.004). The presence of adenovirus colitis was significantly more likely to be associated with chronic diarrhoea (15/21 cases) than adenovirus isolated from stool alone (9/23 cases) (P = 0.03). There was a trend towards an association between adenovirus colitis and colonic cytomegalovirus infection (P = 0.06).

CONCLUSION

Enteric viral infection is strongly associated with acute diarrhoea in patients with HIV. Light microscopic examination of large bowel biopsies can identify adenovirus colitis which is significantly associated with chronic diarrhoea, and in addition may facilitate gastrointestinal co-infection with CMV.

Variability of human systemic humoral immune responses to adenovirus gene transfer vectors administered to different organs

Administration of adenovirus (Ad) vectors to immunologically naive experimental animals almost invariably results in the induction of systemic anti-Ad neutralizing antibodies. To determine if the human systemic humoral host responses to Ad vectors follow a similar pattern, we evaluated the systemic (serum) anti-Ad serotype 5 (Ad5) neutralizing antibodies in humans after administration of first generation (E1(-) E3(-)) Ad5-based gene transfer vectors to different hosts. AdGVCFTR.10 (carrying the normal human cystic fibrosis [CF] transmembrane regulator cDNA) was sprayed (8 x 10(7) to 2 x 10(10) particle units [PU]) repetitively (every 3 months or every 2 weeks) to the airway epithelium of 15 individuals with CF. AdGVCD.10 (carrying the Escherichia coli cytosine deaminase gene) was administered (8 x 10(8) to 8 x 10(9) PU; once a week, twice) directly to liver metastasis of five individuals with colon cancer and by the intradermal route (8 x 10(7) to 8 x 10(9) PU, single administration) to six healthy individuals. AdGVVEGF121.10 (carrying the human vascular endothelial growth factor 121 cDNA) was administered (4 x 10(8) to 4 x 10(9.5) PU, single administration) directly to the myocardium of 11 individuals with ischemic heart disease. Ad vector administration to the airways of individuals with CF evoked no or minimal serum neutralizing antibodies, even with repetitive administration. In contrast, intratumor administration of an Ad vector to individuals with metastatic colon cancer resulted in a robust antibody response, with anti-Ad neutralizing antibody titers of 10(2) to >10(4). Healthy individuals responded to single intradermal Ad vector variably, from induction of no neutralizing anti-Ad antibodies to titers of 5 x 10(3). Likewise, individuals with ischemic heart disease had a variable response to single intramyocardial vector administration, ranging from minimal neutralizing antibody levels to titers of 10(4). Evaluation of the data from all trials showed no correlation between the peak serum neutralizing anti-Ad response and the dose of Ad vector administered (P > 0.1, all comparisons). In contrast, there was a striking correlation between the peak anti-Ad5 neutralizing antibody levels evoked by vector administration and the level of preexisting anti-Ad5 antibodies (P = 0.0001). Thus, unlike the case for experimental animals, administration of Ad vectors to humans does not invariably evoke a systemic anti-Ad neutralizing antibody response. In humans, the extent of the response is dictated by preexisting antibody titers and modified by route of administration but is not dose dependent. Since the extent of anti-Ad neutralizing antibodies will likely modify the efficacy of administration of Ad vectors, these observations are of fundamental importance in designing human gene therapy trials and in interpreting the efficacy of Ad vector-mediated gene transfer.

Shorter survival in HIV-positive patients with diarrhoea who excrete adenovirus from the GI tract

Adenoviruses have been described as a cause of diarrhoea in patients infected with the human immunodeficiency virus (HIV). The prevalence of adenoviruses was studied in all HIV-positive patients presenting with diarrhoea at the Royal Free Hospital in London between 1991 and 1995. In addition, all postmortems carried out in HIV-positive individuals registered at the same centre between 1990 and 1997 were reviewed for evidence of adenovirus infection. Adenovirus was detected in 16.1% of patients presenting with diarrhoea. These individuals had a significantly lower CD4 count and were more likely to have had a diagnosis of acquired immunodeficiency syndrome (AIDS) than patients with diarrhoea in whom adenovirus was not detected. The median survival was 1 year compared with 2.4 years for those without adenoviruses; this difference remained significant (P = .008) after controlling for differences in CD4 counts between the groups. Gastrointestinal adenovirus excretion occurs at an advanced stage of HIV disease, and is associated with a poor prognosis. We suggest that adenoviruses may contribute to mortality in this population.