Friday, June 20, 2014

How HIV Infects You

An HIV Virion - this is what ultimately produces the conditions to kill you

Animation on How HIV Infects You.

This is a really cool video. Unfortunately, it assumes that you know a lot of medical terms and jargon, so it may be a little difficult for most folks to readily understand. But it is understandable, and, for what it addresses, amazingly concise.

To summarize it, the video shows that HIV is really crafty. It is disguised as a normal, healthy cell, but contains within its camouflaged outer protein cell some really nasty RNA (and reverse transcriptase, which converts RNA into DNA when the time comes, and some other stuff necessary to complete the job). This RNA is bad stuff because it is determined to reproduce, and that is really bad for you.

The virus infects T-Helper cells - part of your immune system that is supposed to protect you from stuff like HIV, and which is outside the cell that is about to infected - by having the ability to grab onto T-Helper CD4 cell receptors. Basically, it uses the T-Helper Cell for evil instead of good because it perversely matches the outside of the T-Helper cell, making the T-Helper cell, in essence, think that the viral cell is ok and not dangerous.

The two cells fuse - this leads to the T-Helper cell having the bad RNA inside it. The reverse transcriptase then uses the machinery of the T-Helper cells to turn the viral RNA into DNA inside the T-Helper cell by using host nucleotides. This is bad DNA that will hurt you once it gets inside the target cell - it's harmless in the T-Helper Cell itself, but it doesn't stay there.

This bad DNA is then taken from the T-Helper cell by an enzyme called integrase and into the cell nucleus through a small opening known as a nuclear pore. Once it's inside the cell, you're cooked. The invading DNA finds a target stretch of your good DNA and the integrase splices in the bad, invading DNA.

From there, everything proceeds as normal in DNA reproduction. RNA polymerase comes along, copies the bad DNA thinking it is good DNA into various bad proteins, and messenger RNA takes them back outside the cell via Ribosomes. The outside surface of the cell now has clusters of bad envelope proteins that eventually bud off into your bloodstream and, and some work on poly-protein chains by protease, become full-fledged virions (disease carriers) that go out and re-start the process in other cells.

Each infected cell will produce stuff that hurts you. This process is simply how the virus infects you, then keeps on regenerating itself, sort of like if you have one of those elaborate mousetrap set-ups where one releases, then two, then four, and then pretty much a whole roomful of mouse traps has been set off.

By now, you're sick, though you won't realize it until enough cells are attacked by the virions to ruin your immune system, opening you up to opportunistic diseases that are usually handily kept at bay by a healthy immune system.

I hope I got all that outline right, it's been a while since I cracked those textbooks! I'm sure if you're really up on this you can add all sorts of details and ancillary processes that I left out for the sake of brevity.

It's all kind of spooky why these sorts of heavy viruses exist, which turn your own body against you. That's why HIV is so difficult to fight, it is like a stealth fighter that eludes the enemy radar and drops its payload right on the enemy headquarters. In fact, it makes the enemy fighters think it's one of them, and they escort the enemy fighter right to the target, where it destroys everything.

Fortunately, there are lots of treatments for HIV now that will keep you alive. Eradicating it completely, though, is still not possible. In other words, there is no "cure" in an absolute sense.

If you understand - really understand - everything going on in this animation and can keep all the names straight, you are 90% of the way toward passing any advanced high school or introductory college biology course because this basically is how cells operate normally, but for the first part. And all in under 5 minutes.


No comments:

Post a Comment