NationStates Jolt Archive


Humans have a natural HIV barrier

Sel Appa
06-03-2007, 00:29
Yes, there is a chemical in humans that actively causes cells to "eat" viruses that try to enter the body, including HIV. Because it helps cells "eat" viruses, the viruses will have trouble resisting it, as they would a plain, old chemical.

Link (http://news.yahoo.com/s/hsn/20070305/hl_hsn/scientistsdiscovernaturalbarriertohiv)

MONDAY, March 5 (HealthDay News) -- Researchers have discovered that cells in the mucosal lining of human genitalia produce a protein that "eats up" invading HIV -- possibly keeping the spread of the AIDS more contained than it might otherwise be.

Even more important, enhancing the activity of this protein, called Langerin, could be a potent new way to curtail the transmission of the virus that causes AIDS, the Dutch scientists added.

Langerin is produced by Langerhans cells, which form a web-like network in skin and mucosa. This network is one of the first structures HIV confronts as it attempts to infect its host.

However, "we observed that Langerin is able to scavenge viruses from the surrounding environment, thereby preventing infection," said lead researcher Teunis Geijtenbeek, an immunologist researcher at Vrije University Medical Center in Amsterdam.

"And since generally all tissues on the outside of our bodies have Langerhans cells, we think that the human body is equipped with an antiviral defense mechanism, destroying incoming viruses," Geijtenbeek said.

The finding, reported in the March 4 online issue of Nature Medicine, "is very interesting and unexpected," said Dr. Jeffrey Laurence, director of the Laboratory for AIDS Virus Research at the Weill Cornell Medical College, in New York City. "It may explain part of the relative inefficiency of HIV in being transmitted."

Even though HIV has killed an estimated 22 million people since it was first recognized more than 25 years ago, it is actually not very good at infecting humans, relatively speaking.

For example, the human papillomavirus (HPV), which causes cervical cancer, is nearly 100 percent infectious, Laurence noted. That means that every encounter with the sexually transmitted virus will end in infection.

"On the other hand, during one episode of penile-vaginal intercourse with an HIV-infected partner, the chance that you are going to get HIV is somewhere between one in 100 and one in 200," Laurence said.

Experts have long puzzled why HIV is relatively tough to contract, compared to other pathogens. The Dutch study, conducted in the laboratory using Langerhans cells from 13 human donors, may explain why.

When HIV comes in contact with genital mucosa, its ultimate target -- the cells it seeks to hijack and destroy -- are immune system T-cells. But T-cells are relatively far away (in lymph tissues), so HIV uses nearby Langerhans cells as "vehicles" to migrate to T-cells.

For decades, the common wisdom was that HIV easily enters and infects Langerhans cells. Geijtenbeek's team has now cast doubt on that notion.

Looking closely at the interaction of HIV and Langerhans cells, they found that the cells "do not become infected by HIV-1, because the cells have the protein Langerin on their cell surface," Geijtenbeek said. "Langerin captures HIV-1 very efficiently, and this Langerin-bound HIV-1 is taken up (a bit like eating) by the Langerhans cells and destroyed."

In essence, Geijtenbeek said, "Langerhans cells act more like a virus vacuum cleaner."

Only in certain circumstances -- such as when levels of invading HIV are very high, or if Langerin activity is particularly weak -- are Langerhans cells overwhelmed by the virus and infected.

The finding is exciting for many reasons, not the least of which is its potential for HIV prevention, Geijtenbeek said.

"We are currently investigating whether we can enhance Langerin function by increasing the amount of Langerin on the cell surface of Langerhans cells," he said. "This might be a real possibility, but it will take time. I am also confident that other researchers will now also start exploring this possibility."

The discovery might also help explain differences in vulnerability to HIV infection among people.

"It is known that the Langerin gene is different in some individuals," Geijtenbeek noted. "These differences could affect the function of Langerin. Thus, Langerhans cells with a less functional Langerin might be more susceptible to HIV-1, and these individuals are more prone to infection. We are currently investigating this."

The finding should also impact the race to find topical microbicides that might protect women against HIV infection. Choosing compounds that allow Langerin to continue to work its magic will enhance any candidate microbicide's effectiveness, the Dutch researcher said.

Laurence did offer one note of caution, however.

"In the test tube, this is a very important finding," he said. "But there are many things in the test tube that don't occur when you get into an animal or a human. Having said that, though, this is a very intriguing finding."
Farnhamia
06-03-2007, 00:30
Any advance on the HIV/AIDS front is a good thing. And all the way from the far-flung Isles of Langerhans, too!
Relyc
06-03-2007, 00:36
Lots of potential from the sounds of it.
Fassigen
06-03-2007, 02:19
And all the way from the far-flung Isles of Langerhans, too!

Langerhans cells have nothing to do with the Islets of Langerhans.
Whereyouthinkyougoing
06-03-2007, 02:33
Langerhans cells have nothing to do with the Islets of Langerhans.
Ah, good to know. I was all confused because the vestiges of my high school biology knowledge had placed the latter in the pancreas rather than in the skin. So why do they both have the same name, though? "Discovered" by the same guy, ol' Herr Longjack, or something else?
Yes, I could google it, but why would I when I can just as well ask our resident doctor-to-be?
Fassigen
06-03-2007, 02:59
Ah, good to know. I was all confused because the vestiges of my high school biology knowledge had placed the latter in the pancreas rather than in the skin. So why do they both have the same name, though? "Discovered" by the same guy, ol' Herr Longjack, or something else?
Yes, I could google it, but why would I when I can just as well ask our resident doctor-to-be?

I don't recall right now if he discovered them*, but they are named after the German pathologist Paul Langerhans.

*Quick googling tells me that he did.
Vetalia
06-03-2007, 03:03
I wonder if there are cells in other parts of the body that produce a similar effect, either against HIV or against other viruses? I could see this being used as a powerful antiviral if its underlying mechanisms could be controlled and directed against diseases.
Whereyouthinkyougoing
06-03-2007, 03:03
I don't recall right now if he discovered them*, but they are named after the German pathologist Paul Langerhans.

*Quick googling tells me that he did.:eek: :( And my hippocratic hero's white marble Coat of Knowledge crumbles into a thousand pieces...
Fassigen
06-03-2007, 03:08
:eek: :( And my hippocratic hero's white marble Coat of Knowledge crumbles into a thousand pieces...

There is no Hippocratic oath here, just ethical rules one is obliged to follow without doing something superfluous like reciting a silly oath démodé. As to my knowledge about trivia behind namings and shit, meh.

I wonder if there are cells in other parts of the body that produce a similar effect, either against HIV or against other viruses?

Yes, there are. The whole point with an immune system is that the immune cells themselves are supposed to be able to resist infection, so those are the most obvious examples. Langerhans cells are APCs, so them having this property as well is not exactly earth-shattering.
Lunatic Goofballs
06-03-2007, 03:19
Lots of potential from the sounds of it.

Well, yes. If there were a way to make sure that the body's production of Langerin is kept high, the chances of HIV infection would drop considerably.

In fact, if the action of Langerin can be duplicated synthetically, it might be possible to create a natural and possibly universal anti-viral agent. Of course, that's very optimistic thinking. *nod*
German Nightmare
06-03-2007, 03:27
Langerhans cells have nothing to do with the Islets of Langerhans.
Didn't we have a conversation about that not so long ago?
Fassigen
06-03-2007, 03:28
Didn't we have a conversation about that not so long ago?

Don't expect me to remember things that transpire here. I don't care enough for that.
Sel Appa
06-03-2007, 04:08
Langerhans cells have nothing to do with the Islets of Langerhans.

I thought you meant something in Sweden. :confused:
Fassigen
06-03-2007, 04:10
I thought you meant something in Sweden. :confused:

The Islets of Langerhans can be described as clusters of cells (hence "islets") in the pancreas that deal primarily with blood sugar. The cells that produce insulin, for instance, are located in them.

Sorry about my crappy English and sentence structure. It's very late here and I am very tired.
Whereyouthinkyougoing
06-03-2007, 04:17
The Islets of Langerhans can be described as clusters of cells (hence "islets") in the pancreas that deal primarily with blood sugar. The cells that produce insulin, for instance, are located in them.

Sorry about my crappy English and sentence structure. It's very late here and I am very tired.=) (http://www.alles-herz.com/catalog/images/kissen-inlay.jpg)
Fassigen
06-03-2007, 04:23
=) (http://www.alles-herz.com/catalog/images/kissen-inlay.jpg)

"Nun liebe Kinder gebt fein Acht, ich bin die Stimme aus dem Kissen..."

Aww, I'm trying and all I can say is, lucky work doesn't start until 14, but still. :(
Sel Appa
06-03-2007, 04:25
The Islets of Langerhans can be described as clusters of cells (hence "islets") in the pancreas that deal primarily with blood sugar. The cells that produce insulin, for instance, are located in them.

Sorry about my crappy English and sentence structure. It's very late here and I am very tired.

No No. I thought of islet as some...well islet and then you said what you did and I thought it was in Sweden. You are not at fault, for once. :p
Tainted Visage
06-03-2007, 09:34
YUMMY GOOD NEWS!
*humps*
Pirated Corsairs
06-03-2007, 10:07
They must not allow this to be used to create a potential cure or prevention for AIDS! If kids are shielded against AIDS, they'll learn that all sorts of homosexuality and promoscuity are acceptable! It's a blight upon our American values!
Callin' it before it happens.
Eltaphilon
06-03-2007, 10:56
Callin' it before it happens.

"And thank you God for sending AIDs to kill all the faggots. Amen."