Anti-HIV properties of... bananas?

[insert random collection of Ray Comfort jokes here]

Well, this is a welcome bit of good news!

A lectin isolated from bananas is a potent inhibitor of HIV replication.

Lectins are proteins that bind to specific sugars. For example, in humans, lets say you are infected with Staphylococus aureus. Your human lectins ignore 'your' sugar, but they recognize that the bacteria are making the 'wrong' sugar, and stick to them. This sets off a cascade of events that ends with the bacteria getting blown up.

Swanson et al have found a lectin in bananas ('BanLec', heh) that really likes high-mannose sugars. Well... the HIV-1 envelope is coated in sugar (~50% of its molecular weight!), including high-mannose sugars. So theoretically, if BanLec binds to HIV-1 env before HIV-1 got to cells, BanLec would interfere with envelopes ability to interact with host-cell receptors, thus preventing HIV-1 from being able to infect cells!

!!!

They found that BanLec does inhibit HIV-1s ability to infect cells-- Lab strains and patient isolates, from different subtypes with co-receptor usages.

It competes with a weird HIV-1 antibody, 2G12. This antibody is weird because its conformational and sugar-dependent (you normally dont make antibodies to sugars), so they know BanLec is actually binding to HIV-1, and preventing infection (its not altering the host cells, its binding to virus).

AND BanLecs inhibition abilities are comparable to HIV-1 entry inhibitors already on the market: anti-CD4 antibodies, T-20, and maraviroc.

Taken together, our data suggest that BanLec inhibits infection with a broad range of HIV-1 isolates by blocking viral entry, compares favorably with the potency of previously described lectins and clinically available anti-HIV drugs, and is a potential component for future anti-HIV vaginal microbicides.

Purify this protein from bananas, get it in efficacious doses in microbicides/condoms, stop a bunch of new HIV-1 infections! SWEET!

The only drawback? BanLec is a mitogen (it can cause cancer). *wince* BUT, they might be able to make some artificial modifications to this 'natural' lectin to prevent this, and, no one has evaluated mitogenic dose vs anti-HIV dose, so, there still might be some hope for this.

Random good HIV news.

Oh, and there is not enough of BanLec in bananas for this to be a 'NATUROPATHIC CURE FOR AIDS'. You have to concentrate it, big time, to get a pharmacological dose. So, dont even think about it (I know you already thought about it, dirty monkeys).

More like this

[insert random collection of Ray Comfort jokes here]

Well, duh.

With a banana in either end, there isn't room for any infected 'bananas' to enter.

Would BanLec even survive digestion of the banana to even GET into the blood stream?

Apparently, BanLec-1 can also stimulate T cell proliferation according to this isolation and characterization paper: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1149768/

This is not the only plant-based lectin that have anti-HIV properties. But nifty that it is found in an edible plant.

So bananas cause cancer... I'm doomed... My wife just made a 4 lb. banana/oats pie...

NO! EAT THE FRUIT! /random pop culture references nobody ever gets.

It's a good time to be a banana farmer.
If they can find a way to alter it so that it doesn't cause cancer so easily, then they've got it in the bag. Now we just have to find that damn cure for cancer...

Though IMO I'd also like to see more help for people who already have HIV/AIDS.

You could dilute BanLec a couple hundred fold for the Homeopathic crowd though... Now where did I put that banana smoothie?

Oh, and there is not enough of BanLec in bananas for this to be a 'NATUROPATHIC CURE FOR AIDS'. You have to concentrate it, big time, to get a pharmacological dose.

It makes a change to hear about something that HIV doesn't just laugh at. I think we should immediately commit the entire global bannana harvest to AIDS prevention.

That way I might never have to smell one of the nauseating berries ever again.

Speaking of the naturopaths, I like how A) they claim no one ever researches this stuff because you can't copyright/profit off natural things (tell Colonel Sanders you can't patent herbal mixes), and B) say pharmaceuticals are bad (by virtue of being pharmaceuticals), yet here is a potential pharmaceutical that if developed would be both banana based and a drug. Weird people.

By Party Cactus (not verified) on 15 Mar 2010 #permalink

Well the small amount of BanLec in bananas is a good thing. We'll just label it a homeopathic remdedy. The less there is the more powerful the dose. So we'll take small pieces of banana and dilute it a lot. And then sell that.

Bwahahah!

"I'M SORRY, I CAN'T HEAR YOU! THERE'S A BANANA IN MY... in my...
Wait a minute -- what's it doing in there?"

Does this mean that bananas are going to be sold with a label that says, "For Prevention of Disease Only"?

Actually, it's really, really nice to find out that something that's cheap and grows on trees may have major unexpected benefits.

By TotallyUncool (not verified) on 15 Mar 2010 #permalink

Well, since bananas fit in your hand so perfectly, and are proof of creation, doesn't this make sense?

Mitogen? Induces cell division rather than mutagen (induces mutation).

Many lectins induce lymphocyte division (PHA) and while they are not nice things they don't intrinsically cause tumours.

With a banana in either end, there isn't room for any infected 'bananas' to enter.

Uhm.
No, actually, never mind, move along now....:-)

By Rorschach (not verified) on 16 Mar 2010 #permalink

Would BanLec even survive digestion of the banana to even GET into the blood stream?

Most proteins are partially, if not totally degraded in the stomach before moving onto the gut. However, thanx to the wonders of stoichiometry, a small amount of proteins do make it through relatively intact. These are passed through gut m-cells to the underlying mucosa, where your body does things with them like prevent food allergies.

I'm sure a sensitive enough assay would be able to pick them up in blood; but I doubt they'd have any functional consequences.

More likely than not, these will have to be packaged in a way that gets them past the stomach, if the mitogen issue can be overcome.

Mitogen? Induces cell division rather than mutagen (induces mutation).

But can still lead to cancer. Elevated rates of cell division often lead to mutation, simple because on an accelerated cell division "schedule" cells simply lack the time to correct replication errors. Many pathogen-derived mitogens are known to increase the likelihood of cancer.

This adds a whole new dimension to banana-flavored condoms.

"This antibody is weird because its conformational and sugar-dependent (you normally dont make antibodies to sugars)"

Au contraire; as you yourself pointed out a while back the ABO blood group antigens are sugars attached to lipids.

By Albatrossity (not verified) on 16 Mar 2010 #permalink

Is that a low nanomolar potent HIV-1 cellular entry inhibitor in your pocket...

or are you just happy to seem me?

By Scientizzle (not verified) on 16 Mar 2010 #permalink

I'm sure teh naturopaths will have better patient compliance with topical banana application for HIV prophylaxis than than they would with urtica dioica agglutinin, a lectin found in stinging nettles .... ow.
NCI turned up the stinging nettle lectin years ago in an antiviral screen; last I heard trials using it in a topical prep as a microbicide (minus the stinging bit!) didn't succeed for HIV prevention.

Re: #2 and #15

Thanx ImagingGeek.

That's pretty much what I though, that the proteins would be mostly broken down by digestion.

@JimNorth #7 and @Joshua Zelinsky #10:

No no no, you guys have it all wrong. If the homeopaths are right, and if concentrated BanLec really inhibits HIV activity, then dilute BanLec should cause HIV to spontaneously pop into existence. KILLER BANANAS!

another jokes for all the suckers