HIV Transmission Captured On Video 136
Technology Review has promising news on the AIDS front: researchers have captured HIV T cell transmission on video. The upshot could be new avenues of treatment. "The resulting images and videos show that, once an infected cell adheres to a healthy cell, the HIV proteins... migrate within minutes to the contact site. At that point, large packets of virus are simultaneously released by the infected cell and internalized by the recipient cell. This efficient mode of transfer is a distinct pathway from the cell-free infection that has been the focus of most prior HIV studies, and reveals another mechanism by which the virus evades immune responses that can neutralize free virus particles within the body."
Sure it's not an artifact? (Score:1, Interesting)
Protein dynamics can be affected by alterations to the protein itself. In this case, the gag protein had GFP inserted into it. GFP itself dimerizes weakly, and would add some size and weight to the protein. Does anyone know how they are sure what they're seeing matches normal Gag dynamics? The paper says "This virus faithfully reveals Gag localization, allowing infected cells and viral particles to be tracked with high sensitivity" citing an earlier paper by the same authors. That paper showed that it was not behaving like GFP alone (and was mostly over my head), but I didn't notice anything that proved the modified GAG behaved exactly like normal GAG. The protein does seem to be doing it's job and helping the virus infect, which suggests it's not rendering GAG useless, but doesn't prove it behaves in the exact same way.
It seems to me that if you're going to say "large packets of virus are simultaneously released by the infected cell and internalized by the recipient cell" that you should be sure those large packets of virus are normal and not just a result of adding GFP onto it. I'm not a virologist though, so I'm probably just missing something.
Re:Fascinating (Score:3, Interesting)
Re:If only HIV killed instantly.. (Score:2, Interesting)
Google the term "bugchasing."
There's a subset of the gay community whose philosophy is basically that since we're all going to die anyway, they might as well get HIV so they can stop worrying about getting HIV.
Then if you really want your mind fucked with, Google "giftgiving."
AIDS pulling a revolutionary new trick (Score:5, Interesting)
I think the interesting part about this discovery is that aids is traveling from cell to cell without the need to release virons to float around hoping to find a cell. I don't recall hearing about any other virus that spreads by cell-to-cell contact. It appears as though the infected cell press up against an uninfected cell, form a pocket between them (that is not connected to "outside" and then release some virons into this pocket. The virons contain the necessary "key" to get into a cell, but normally their odds are not good simply because they have to float around and hope to bump into a T cell, one at a time, in just the right way.
This process has several advantages. First, it's not wasting virons by simply multiplying them inside the cell until the cell bursts, leaving the virons to float around hoping for a chance contact. Second, since the body isn't being flooded with virons, it severely delays and slows the auto immune response of the body which isn't going to react anywhere near as fast to such a low-volume threat of a handful of virons leaking out now and then vs thousands popping onto the scene continually. Third, in addition to being hand-delivered to a target cell, there's a ton of them at the contact site concentrated right on the target cell's doorstep, not just one, so infection is pretty much guaranteed.
It's sort of the difference between a country sending an "army" to their enemy, by stirring up a villagefull of people to go attack on their own individually, vs assembling a strike force and attacking at one spot on the wall all at once. Clearly the latter is more effective.
Scarry stuff. AIDS looks to have evolved a very potent new method of infection. It's too bad we don't know more about how this process works. AIDS is probably throttling its viron production so the infected cell survives to infect other cells, rather than multiplying virons as fast as possible to get the most of them released into the body as fast as possible. Interferfon iirc slows the replication of AIDS virons inside the cell, so it makes sense that throttling an already throttled process should be an effective treatment.
If a cell has been taken over and is personally going to another cell and staging an attack, this may be a very difficult problem to overcome. Small, relatively inert virons can only hope for a chance contact in just the right way with a target cell. An entire cell coming to get you is a bit more like a bacteria problem, they have a heck of a lot more resources at their disposal. It's like the enemy taking over one of your tanks, vs coming at you as a walking soldier. Difference is, when the enemy "gets you", he doesn't destroy your tank... he dumps some men INTO your tank and now he has TWO tanks.
What this all boils down to is AIDS has found a new way to use the cells it hijacks. Most other viruses use them as self-destructing viron factories, and a few as places to hide and lay dormant for later relapse. But using cells as lingering attack platforms is just plain scarry.