A Vaccine for HIV?

Let’s face it. HIV is a pretty scary virus. There is no cure or vaccine available in the market to help you. It doesn’t matter whether you’re a hotshot businessman loaded with cash or a homeless dude begging in the streets. Once you get infected, you’re in for a lifetime of medication. The only way be free of HIV is to prevent infection in the first place.

20150214_071714Don’t let your affection give you an infection. (yes, I’m using this photo again)

Given the prevalence of HIV infection around the world, research is actively being done to combat this virus. You’d think that scientists should have figured out this problem long ago and that the only reason people are not getting a cure is because of Big Pharma. But before you scare the shit out of people with conspiracy theories, consider that the biology of the HIV makes it incredibly hard to defeat.

HIV mechanism

HIV is one slippery son of a gun. First, it’s a virus that attacks your immune cells. In particular, it preferentially targets your helper T cells (CD4+ lymphocytes in nerd speak) responsible for mounting an effective immune response. That’s right, it screws you over by turning cells sworn to protect you into HIV making machines. Second, it mutates so easily that the body is essentially blind to the HIV infection. For instance, the envelope glycoprotein that surround the viral genetic material changes rapidly. It’s so prone to changes that antibodies used to bind to them are rendered useless after a while.



Potential Vaccine?

Now, scientists from The Scripps Research Institute (TSRI) have announced the creation of a novel drug candidate that blocks every strain of HIV including the hardest-to-stop variants. In their study published in Nature, they reported that the drug candidate efficiently neutralized 100% of all tested viral isolates.

This drug was created by fusing the proteins,CD4-Ig and a modified CCR5 co-receptor, into a protein called eCD4-Ig that selectively bind to two conserved regions within the viral envelope glycoprotein, Env.

Whew, that was a mouthful. But that sentence effectively summarizes what the scientists have done. For the sake of a conceptual overview, it doesn’t matter what those two proteins are. What matters is that they bind to conserved regions within Env. It’s important because I’ve mentioned earlier that this envelope is highly prone to mutations.


I understand that the sentence summary above is complicated for non-technical readers out there. So let’s bring the news to a comfortable level of comprehension. To understand how this vaccine is such a breakthrough, imagine that HIV is an elite force of a global terrorist group. Think of HIV as a highly trained infiltration unit who are masters in the art of disguise. The police have such a hard time of tracking these terrorists because they keep changing their appearance.

It can be argued how a terrorist looks like but here’s what the media is feeding us. That’s also a social science topic lol

Through painstaking investigation, let’s say that the police has established that the HIV terrorists have two tattoos in their body that mark them as HIV members; one in each thigh. These tattoos are definitive markers because it’s what identifies them as part of the HIV terrorist arm. They’re hidden from view but the police can easily check for these tattoos.

In a nutshell, eCD4-Ig targets these “tattoos” of the HIV. Stretching our analogy further, you can think of the “tattoos” as the conserved regions crucial to the entry of the HIV virus to its host cell. Obviously, if the virus mutates critical elements of Env too much then it couldn’t enter the cell. eCD4-Ig effectively targets not just one but two conserved regions of Env thereby ensuring its binding. When the binding event happens, they’re marked as HIV and are now on the hit list of the police (the immune system).

Gene Therapy

The Scientists didn’t just stop with the production of the fusion protein. It’s a very effective agent against HIV but it wouldn’t work in a vaccine-like manner if your body can’t produce it on its own. How do you insert a gene sequence that instructs cells to produce the fusion protein?

You use a virus.

Paradoxically, the scientists used a virus to prevent the Rhesus macaques in the study from getting infected by HIV. Of course, this wasn’t an ordinary virus. It’s an engineered adenovirus that has been modified to deliver a genetic payload without causing harm to a cell.And for at least 34 weeks, the Rhesus macaques in the experiment were protected from HIV infection even after getting injected by amounts of the virus too high to be transmitted naturally.


Okay, that sounds complicated as well. But the adenovirus simply just gave instructions to your cell on how to look for the HIV. To stretch our terrorist analogy even further, imagine that the adenovirus is a captured terrorist that squealed information on how to identify our HIV terrorists. They tell your cells to look for the “tattoos” of HIV so that they can be dealt with swiftly and severely.

This is the wanted list for the 9/11 bombing. The immune system does an analogous job of cataloging “terrorists” too

Further Studies Needed

Aside from your usual gang of anti-vaxxers who outrightly abhor the very notion of a new vaccine, there are many other hurdles to be overcome before this vaccine ends up in your local clinic. For one thing, there hasn’t been any human clinical trials yet. The scientists also have assess the effect of the fusion protein constantly getting produced in your body. Moreover, they need to extend the period of protection from HIV to work as a viable vaccine.

However, the Science behind their technique is incredible. It truly reflects decades of work probing the biochemistry of the HIV. This paper shows how the research effort to create an anti-HIV vaccine is taking the right steps in the right direction.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s