February 3, 2014
Getting A Really Close Look At HIV
Ask anyone what one of the ailments of our age is and I am fairly certain that many of them will say HIV/AIDS, and why would they say otherwise? Growing up in the late 80’s and 90’s, people always seemed to be talking about HIV and AIDS. Even now, it is still used as a tactic to scare our youth into abstinence. Seriously, I remember some of the text in Health class being little more than “sex before marriage WILL give you AIDS,” and while that is most certainly over-exaggerating it, that does not make HIV/AIDS any less terrible. AIDS has claimed the lives of more than 35 million people worldwide and is believed to currently infect an estimated 34 million more. While there is hope that we may have found a potential cure, there is still a lot we do not know about this awful virus, despite it being first reported just over 30 years ago. Hopefully, that is about to change.
Researchers at the California Institute of Technology (Caltech) recently used a high-resolution electron microscope to look at the HIV virus under a whole new light. Using an animal model they implanted with human tissue from the intestinal tract, they were able to get a look at how the HIV infection works. To do this, they used a technique called electron tomography, where a tissue sample is embedded in plastic and placed under the microscope. The sample is then incrementally tilted a full 120 degrees, with pictures being taken at one-degree intervals. Once this was done, all of the collected images were aligned with one another so that they could create a three dimensional reconstruction of the virus. This was repeated time and time again so that they were given a complete look at just how the virus works once it has infected a host. They had to be very careful with this experiment – thus, the implanted animal model – because the virus itself is an infectious agent. However, what they gained from these tests is already proving that the risk was worth it. This was the first time ever that researchers were able to look at HIV in what is, for the most part, normal circumstances.
What they discovered was that HIV does not release newly formed viruses at random. Rather, infected cells release newly formed viruses in a “semisynchronous wave pattern,” according to Mark Ladinsky, lead microscope scientist at Caltech. “Groups of virus bud off from a given cell within a certain time frame and then, a little while later, another group does the same, and then another, and so on.” They also witnessed that the virus was actually able to spread via direct contact with neighboring cells rather than simply by these waves of new viruses. Finally, they also found pools of the virus growing between cells where no other indication of a virological synapse had taken place. What this suggests is that the virological synapse is not the only way in which HIV can infect new cells. This discovery offers potential hope for a new treatment with more protein-based drugs, such as tailored antibodies, rather than using the current regimen of small-molecule antiretroviral drugs.
Nothing comes without risk, but I am glad that this risk has paid off. Further study into the HIV/AIDS virus may someday soon lead us to a cure, and when that day comes, I am confident that it will be in no small way due to the hard work done by the team at Caltech.
Image Credit: Mark Ladinsky / Caltech