Host: Vincent Racaniello
Guests: Alan Dove and Jeremy Luban
Vincent, Alan, and Jeremy discuss why certain AIDS patients, called ‘elite controllers’ or ‘long-term non-progressors’, do not develop disease, why mosquitoes infected with Sindbis virus remain healthy, and the continuing outbreaks of norovirus gastroenteritis.
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Links for this episode:
- Immunity article on elite controllers.
- PNAS article on protected mosquitoes.
- The word quarantine comes from the seventeenth century Venetian quarantena, which means forty day period.
Science podcast pick of the week: The Mr. Science Show
Science book of the week: Arrowsmith by Sinclair Lewis. Click here to see a page from my Mother’s marked-up copy. She was a high school English teacher.
Send your virology questions to twiv@microbe.tv
The topic of long-term non-progressors is really interesting. What is it about these individuals that allow them to survive with the virus and not develop AIDS?
I remember reading a few years ago that throughout northern Europe a percentage of individuals have CCR5-Δ32 which is a variant of the CCR5 HIV coreceptor and that CCR5-Δ32 seems to confer protection against HIV . Wikipedia confirmed my memory regarding the reason for this when I read “It has been hypothesized that this allele was favoured by natural selection during the Black Death, but this is unlikely, given that the frequency of CCR5-Δ32 in Bronze Age samples is similar to that seen today..” here http://en.wikipedia.org/wiki/CCR5.
So it turns out that the “multiple plague hypothesis”(as I am calling it) is not supported.
What do you think the reason is for the CCR5-Δ32 prevalence in the northern European populations?
It has been reported that CCR5 (and other chemokine receptors) can facilitate infection by myxoma virus , vaccinia virus, and other poxviruses. (Lalani, A. et al. use of chemokine receptors by poxviruses. Science 286:1968-1971. 1999). If true for variola (smallpox virus), then smallpox is the leading candidate for the selective pressure responsible for fixation of the CCR5delta 32 HIV-resistance allele in modern Caucasians. Perhaps the survivors of smallpox epidemics are “enriched” for CCR5 mutations.
It has been reported that CCR5 (and other chemokine receptors) can facilitate infection by myxoma virus , vaccinia virus, and other poxviruses. (Lalani, A. et al. use of chemokine receptors by poxviruses. Science 286:1968-1971. 1999). If true for variola (smallpox virus), then smallpox is the leading candidate for the selective pressure responsible for fixation of the CCR5delta 32 HIV-resistance allele in modern Caucasians. Perhaps the survivors of smallpox epidemics are “enriched” for CCR5 mutations.