Virology News

Survival of infection with Ebola virus (EBOV) depends on the ability of the host to mount early and strong immune responses [1], [2]. However, given that EBOV cases are associated with 40%–90% human mortality, EBOV has developed intricate solutions to human immunological defenses. Enveloped viruses, like EBOV, must deposit their genetic material within a cell to ensure their propagation. The roles of viral envelope glycoproteins in mediating virus attachment to host cells and catalyzing the subsequent fusion of the viral and host plasma membranes have been well described (reviewed in [3]). Given the limited number of genes in EBOV and other viruses, it stands to reason that these conformationally labile glycoproteins are also involved in more than just the initial steps of a productive infection. There is strong evidence that viral entry glycoproteins (GP) are modulators of host antiviral defenses (Table 1). In this article, we discuss our current structural understanding of the functions of envelope entry glycoproteins in immune evasion using EBOV as our example.

The 2009 swine-origin H1N1 influenza, though antigenically novel to the population at the time, was antigenically similar to the 1918 H1N1 pandemic influenza, and consequently was considered to be [ldquo]archived[rdquo] in the swine species before reemerging in humans. Given that the H3N2 is another subtype that currently circulates in the human population and is high on WHO pandemic preparedness list, we assessed the likelihood of reemergence of H3N2 from a non-human host. Using HA sequence features relevant to immune recognition, receptor binding and transmission we have identified several recent H3 strains in avian and swine that present hallmarks of a reemerging virus. IgG polyclonal raised in rabbit with recent seasonal vaccine H3 fail to recognize these swine H3 strains suggesting that existing vaccines may not be effective in protecting against these strains.

Vaccine strategies can mitigate risks associated with a potential H3N2 pandemic in humans.

In the mid-2000s, David Markovitz, a scientist at the University of Michigan, and his colleagues took a look at the blood of people infected with HIV. Human immunodeficiency viruses kill their host...

The entire replication cycle of picornaviruses takes place in the cytosol. Or does it?

The RV144 ‘Thai trial’ of an HIV vaccine candidate resulted in an unprecedented 31% protection rate among participants – a

result that sparked something of a revival in the HIV vaccine field. Despite this encouraging result, the protection rate was still considered to be too low for the vaccine to be useful. Since then, many HIV vaccines have come and gone – with the NIAID’s HVTN 505 trial being the latest casualty in the drive to stem the HIV pandemic. However, researchers at the Duke Human Vaccine Institute have published researched inProceedings of the National Academy of Sciences (May 6th 2013) which pinpoints a previously unknown interaction between IgA and IgG antibodies as the cause of a lack of response to the RV144 vaccine.

Killer T-cell graphic by Russell Kightely Media

The World Health Organization warns that it appears "increasingly" likely that the new coronavirus can be passed between people in close contact.

World Vaccine Congress & Expo 2013 

Dr Thomas P. Monath, Adjunct Professor at Harvard School of Public Health gives his presentation on ‘New vaccines needed for pathogens infecting animals and humans: One Health’.

Scientists say a disease destroying entire crops of cassava has spread out of East Africa into the heart of the continent, is attacking plants as far south as Angola and now threatens to move west into Nigeria, the world's biggest producer of the potato-like root that helps feed 500 million Africans.

Photo: healthy cassava, Ed Rybicki, western Kenya, 1998

Psittacine beak and feather disease, caused by beak and feather disease virus (BFDV), is a threat to endangered psittacine species. There is currently no vaccine against BFDV, which necessitates the development of safe and affordable vaccine candidates. A subunit vaccine based on BFDV capsid protein (CP), the major antigenic determinant, expressed in the inexpensive and highly scalable plant expression system could satisfy these requirements. Full-length CP and a truncated CP (ΔN40 CP) were transiently expressed in tobacco (Nicotiana benthamiana) as fusions to elastin-like polypeptide (ELP). These two proteins were fused to ELPs of different lengths in order to increase expression levels and to provide a simple means of purification. The ELP fusion proteins were purified by inverse transition cycling (ITC) and it was found that a membrane filtration-based ITC method improved the recovery of ΔN40 CP-ELP51 fusion protein relative to a centrifugation-based method.

This study shows that the oral administration of rotavirus VP6-VHH nanoAb is a broadly reactive and effective treatment against rotavirus-induced diarrhea in neonatal pigs. Our findings highlight the potential value of a broad neutralizing VP6-specific VHH nanoAb as a treatment that can complement or be used as an alternative to the current strain-specific RVA vaccines. Nanobodies could also be scaled-up to develop pediatric medication or functional food like infant milk formulas that might help treat RVA diarrhea.

Infection with influenza virus leads to significant morbidity and mortality. Annual vaccination may prevent subsequent disease by inducing neutralizing antibodies to currently circulating strains in the human population. To escape this antibody response, influenza A viruses undergo continuous genetic variation as they replicate, enabling viruses with advantageous antigenic mutations to spread and cause disease in naïve or previously immune or vaccinated individuals. To date, the 2009 pandemic virus (A(H1N1)pdm09) has not undergone significant antigenic drift, with the result that the vaccine remains well-matched and should provide good protection to A(H1N1)pdm09 circulating viruses. In this study, we induced antigenic drift in an A(H1N1)pdm09 virus in the ferret model. A single amino acid mutation emerged in the dominant surface glycoprotein, hemagglutinin, which had a multifaceted effect, altering both antigenicity and virus receptor specificity. The mutant virus could not be isolated using routine cell culture methods without the virus acquiring additional amino acid changes, yet was fit in vivo. The implications for surveillance of circulating influenza virus are significant as current assays commonly used to assess vaccine mismatch, as well as to produce isolates for vaccine manufacture, are biased against identification of viruses containing only this mutation.

Influenza virus graphic by Russell Kightley Media 

The new H7N9 bird flu strain has been found to be a mixture of genes from four flu strains found in birds even as the first patient with severe symptoms of the deadly disease has made a complete recovery.

The aims of the study were to evaluate current strategies used for the monitoring of HPV infection in genital warts and to assess the suitability of laser-capture microdissection (LCM) as a technique to improve the understanding of the natural history of HPV types associated with genital wart lesions.

DNA and RNA were extracted from whole wart, surface swabs and LCM sections from 23 patients. HPV types present were determined using the Linear Array HPV Genotyping Test (Roche), with HPV DNA viral load and mRNA expression investigated using qPCR and qRT-PCR, respectively.

Results indicated that swabbing the surface of warts does not accurately reflect potential causative HPV types present within a wart lesion, multiple HPV types being present on the surface of the wart that are absent in the lower layers of tissue isolated by LCM. Although it was shown that HPV DNA viral load does not directly correlate with HPV mRNA load, the presence of both DNA and mRNA from a single HPV type suggested a causative role in lesion development in 8/12 (66.6%) of patients analysed, with dual infections seen in 4/12 (33.3%) cases. HPV 6 and HPV 11 were present in more than 90% of the lesions examined.

HPV graphic courtesy of Russell Kightley Media