Posts Tagged ‘SIV’

PLoS Pathogens: ADCC Develops Over Time during Persistent Infection with Live-Attenuated SIV and Is Associated with Complete Protection against SIVmac251 Challenge

24 August, 2012

See on Scoop.itVirology and Bioinformatics from Virology.ca

“Here we show that live-attenuated SIV induces progressive increases in ADCC over time, and that the development of these antibodies is dependent upon the persistent replication of the vaccine strain. In two different experiments, the animals immunized with live-attenuated SIV that remained uninfected after pathogenic SIV challenge had higher measures of ADCC than those that became infected. Our results suggest that antibodies contribute to protection by live-attenuated SIV, and that persistent stimulation of antibody responses may be essential for HIV-1 vaccines to induce high ADCC activity.”

 

Shit HOT results, in that they demonstrate that – as some have said repeated ly over years – that neutralising Ab are NOT necessarily the Holy Grail, and that ADCC and other mechanisms are also really important.  Good Stuff…B-)

See on www.plospathogens.org

Gag-Specific Cellular Immunity Determines In Vitro Viral Inhibition and In Vivo Virologic Control following Simian Immunodeficiency Virus Challenges of Vaccinated Rhesus Monkeys

24 August, 2012

See on Scoop.itVirology News

“We observed that CD8+ lymphocytes from 23 vaccinated rhesus monkeys inhibited replication of SIV in vitro. Moreover, the magnitude of inhibition prior to challenge was inversely correlated with set point SIV plasma viral loads after challenge. In addition, CD8 cell-mediated viral inhibition in vaccinated rhesus monkeys correlated significantly with Gag-specific, but not Pol- or Env-specific, CD4+ and CD8+ T lymphocyte responses. These findings demonstrate that in vitro viral inhibition following vaccination largely reflects Gag-specific cellular immune responses and correlates with in vivo virologic control following infection. These data suggest the importance of including Gag in an HIV-1 vaccine in which virologic control is desired.”

 

In other words: having Gag or a gag gene included in a vaccine against SIV given to monkeys was more important than having Pol or Env when it came to control of virus replication – although, as has been shown elsewhere, Env responses are important for protecting against acquisition.  This has important implications for human vaccines – although “monkeys aren’t men, and mice lie” – and in particular for the South African SAAVI vaccines, which elicit quite good Gag-specific cellular responses.

 

We wait in hope.  Graphic showing immune cells associated with HIV control courtesy of Russell Kightley Media.

See on jvi.asm.org

When dinner could kill you: smoked chimpanzee, anyone?

14 January, 2012

ProMED Mail this morning had a rather alarming item: “BUSHMEAT TRADE, DISEASE TRANSMISSION RISK”.  They reported on a study, highlighted in a BBC report, of possible pathogens imported into the USA via bushmeat from Africa, confiscated at airports.  This in turn derived from a PLoS One paper – “Zoonotic Viruses Associated with Illegally Imported Wildlife Products“, by Kristine Smith et al., published on January 10th 2012.  Their abstract:

The global trade in wildlife has historically contributed to the emergence and spread of infectious diseases. The United States is the world’s largest importer of wildlife and wildlife products, yet minimal pathogen surveillance has precluded assessment of the health risks posed by this practice. This report details the findings of a pilot project to establish surveillance methodology for zoonotic agents in confiscated wildlife products. Initial findings from samples collected at several international airports identified parts originating from nonhuman primate (NHP) and rodent species, including baboon, chimpanzee, mangabey, guenon, green monkey, cane rat and rat. Pathogen screening identified retroviruses (simian foamy virus) and/or herpesviruses (cytomegalovirus and lymphocryptovirus) in the NHP samples. These results are the first demonstration that illegal bushmeat importation into the United States could act as a conduit for pathogen spread, and suggest that implementation of disease surveillance of the wildlife trade will help facilitate prevention of disease emergence.

What was even more horrifying were the pictures of confiscated items – herewith their Figure 1.

doi:10.1371/journal.pone.0029505.g001

It boggles my mind how anyone could even consider smuggling this sort of thing into anywhere – and I am hoping that the US Customs has the same sorts of detection mechanism – as in, well-trained beagles – as they used to have in Miami Airport to detect biltong [dried spiced meat] smuggled in from South Africa.  Those dogs were seriously good – trouble is, they really loved the biltong they got as a reward, too, and it makes my skin crawl rather to imagine a beagle salivating over smoked vervet monkey.

The ProMED post comments further:

No one really knows the scale of the illegal trade in wildlife meat, or bushmeat as it is often called, but a 2010 study estimated that 5 tonnes of the material per week was being smuggled in personal baggage through Roissy-Charles de Gaulle airport in Paris, France. And in addition to the meat products, there is a big trade in live wild animals. Much of this is perfectly legal and supplies the pet industry. Nonetheless, these animals also require improved pathogen surveillance, say the researchers.

One has only to remember that the monkeypox outbreak in the USA in recent times originated in an African animal imported live – see Viroblogy here – to realise the potential danger posed by international movement of wild-caught animals – or even of laboratory animals, as happened in the Ebola Reston incident.

The list of animals from whom parts were found is also rather disturbing: this included chimpanzee, sooty mangabey, and “green monkey” or vervet.  Virologists will not need reminding, but others may, that HIV-1 originated in chimpanzees and HIV-2 in mangabeys – and that although these viruses were not found this time, the PLoS One paper notes:

“Although we did not find SIV or STLV in the limited number of specimens in this study, these viruses have been found in high prevalences in NHP specimens at bushmeat markets and in hunted NHPs [8], [32], [33]. HIV-1 and HIV-2 emerged as a result of several spillover events of SIV from chimpanzees and mangabeys, respectively, that were likely hunted for bushmeat in central and western Africa [30]. Serosurveillance studies have shown thirty-five different species of African NHPs harbor lentivirus infections, with a prevalence of SIV in up to 35% of free-ranging chimpanzees, and 30–60% of free-ranging sooty mangabeys and green monkeys [30], [31], [33], [34].”

So really, it is just a matter of time before meat that contains SIVs or STLVs gets through into the USA and other world centres – and a whole new wave of zoonotic infection could start.  It really is inexcusable that people living in developed countries should be importing meat derived from endangered species in the first place.  It is made worse that developed countries like the USA find it necessary to import LIVE animals as pets – and while the monkeypox outbreak was caught early, the next one may not be.

So forget the “engineered” H5N1 paranoia, folks – be a LOT more scared of the cute rodent in a cage near you, or what your neighbour may be eating….