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Biotech Science

Crocodile's Immune System Kills HIV 628

ASEville writes "In an ongoing effort to stop the spread of HIV, scientists in Australia have discovered that crocodiles can fight off HIV and kill the virus. This is a major boon to medicine because the crocodile serum can also fight things that are penicillin resistant such as staphylococcus aureus."
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Crocodile's Immune System Kills HIV

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  • by zegebbers ( 751020 ) on Wednesday August 17, 2005 @02:10AM (#13336921) Homepage
    Was carried out by Professor Wilkins in addition to HIV research he also is responsible for tractor mainentance.
  • Crikey! (Score:3, Funny)

    by TheOtherAgentM ( 700696 ) on Wednesday August 17, 2005 @02:11AM (#13336924)
    Sweet! Now Steve Irwin, The Crocodile Hunter, will be even more popular.
  • Great... (Score:5, Funny)

    by Premo_Maggot ( 864012 ) <nessnoop@gmail.com> on Wednesday August 17, 2005 @02:11AM (#13336926) Homepage
    Now all we have to do is kill off all the crocodiles for the serum we need.
    • by tentimestwenty ( 693290 ) on Wednesday August 17, 2005 @09:52AM (#13338557)
      If something from a Crocodile can teach us how to cure AIDS in humans, what about all the endangered or extinct species? Maybe this will bring some more attention to the fact that we NEED other species around to learn from and co-habitate with. It would really suck if we killed off some kind of plant that was going to hold the key to solving a horrible disease of the future.
      • by default luser ( 529332 ) on Wednesday August 17, 2005 @11:56AM (#13339743) Journal
        It would really suck if we killed off some kind of plant that was going to hold the key to solving a horrible disease of the future.

        Conversely, it would really suck if a new mutation of a plant appeared in the future that could cure a horrible disease...and was subsequently overwhelmed by plants that we'd saved.

        It's a two-way street. If species don't die off, new ones can't flourish. Don't pretend that you can comprehend what's best for a system as large as the earth.

        Anyway, it's not as if it would be catastrophic if say, an entire species of crocodiles died tomorrow - there are hundreds of species of crocodile, and most are very similar in characteristics. The article doesn't mention a specific species of crocodile because it's probably not important.

        Same goes for any other species.
  • by Brainboy ( 310252 ) <iamchillinNO@SPAMgmail.com> on Wednesday August 17, 2005 @02:13AM (#13336931) Journal
    ...How many animals they tested before they found crocodile fought off HIV?

    Scientist: Perhaps pigs can fend off HIV?
    *Lab_Assistant injects Porky with HIV
    *Porky leaves channel (AIDS)
    Scientist: Nope! Time to try eagle next!
  • by jazzman251 ( 887873 ) on Wednesday August 17, 2005 @02:13AM (#13336934)
    HIV kills crocodiles!!
  • by ChrisKnight ( 16039 ) <merlin@noSpAm.ghostwheel.com> on Wednesday August 17, 2005 @02:15AM (#13336938) Homepage
    "If you take a test tube of HIV and add crocodile serum it will have a greater effect than human serum. It can kill a much greater number of HIV viral organisms,"

    Ummm.... So? The same thing can be said of chlorine bleach.

    There are lots of known chemicals that kill HIV. The trick is finding one that leaves the patient alive. I know the /. editors don't read the articles submitted all the way to the end, so here's a bit towards the end that really matters:

    "However, the crocodile's immune system may be too powerful for humans and may need to be synthesized for human consumption."

    There is nothing in the article to suggest that they have isolated the specific component that kills HIV, let alone determined that it is safe for human injection.

    -Chris
    • by Anonymous Coward on Wednesday August 17, 2005 @02:24AM (#13336977)
      "There is nothing in the article to suggest that they have isolated the specific component that kills HIV, let alone determined that it is safe for human injection."

      I know the /. commentor's don't read the articles submitted all the way to the end, so here's a bit towards the end that really matters:

      "The scientists hope to collect enough crocodile blood to isolate the powerful antibodies and eventually develop an antibiotic for use by humans ... There is a lot of work to be done. It may take years before we can get to the stage where we have something to market," said Britton.
    • by quantaman ( 517394 ) on Wednesday August 17, 2005 @02:39AM (#13337029)
      "If you take a test tube of HIV and add crocodile serum it will have a greater effect than human serum. It can kill a much greater number of HIV viral organisms,"

      Ummm.... So? The same thing can be said of chlorine bleach.

      There are lots of known chemicals that kill HIV. The trick is finding one that leaves the patient alive. I know the /. editors don't read the articles submitted all the way to the end, so here's a bit towards the end that really matters:

      Yes but I'm guessing that bleach along with most of those chemicals will also kill crocodiles. The encouraging part here is they've found something that leaves crocodiles alive, there's a good chance that if it leaves a crocodile alive and kills the virus it may be able to do the same for humans.
    • by Vellmont ( 569020 ) on Wednesday August 17, 2005 @02:55AM (#13337085) Homepage

      Ummm.... So? The same thing can be said of chlorine bleach.

      True, but since this agent doesn't kill or harm crocodiles there's a decent chance it'll be safe for humans.

      There is nothing in the article to suggest that they have isolated the specific component that kills HIV, let alone determined that it is safe for human injection.

      Very true. It's called research. You start with knowing very little, and eventually you might get something usefull. They're still at the knowing very little stage. Maybe they might get to the knowing a bit more stage sometime later.

      I guess what I'm confused by is why you expected some announcement of a cure. Haven't you ever seen articles that talk about new research, breadcrumbs of information, etc? The answers don't arrive all in one big piece. This article merely talks about one stage of one search.
    • Unfortunately, the whole article appears to have been written by someone who was biologically illiterate:

      Scientists in Australia's tropical north are collecting blood from crocodiles in the hope of developing a powerful antibiotic for humans, after tests showed that the reptile's immune system kills the HIV virus.

      Since antibiotics are agents that kill bacteria rather than viruses, this paragraph is a non sequitur.

      Similarly, the phrase However, the crocodile's immune system may be too powerful for humans mak
      • Odd phrasing aside, this research has been going on for a while. They have isolated one protein that has proven to be a very powerful antibiotic. My guess is they may have found or are trying to isolate another that functions as an anti-viral.

        Oddly enough, the research started when someone decided to look into why crocodiles, who get injured all the time in fights and live in muck, never seemed to get infections from their injuries.
      • by krayzkrok ( 889340 ) on Wednesday August 17, 2005 @09:39AM (#13338430) Homepage
        Well Mr Angostura, you're as bitter as your namesake aren't you?
        First of all, if it isn't clear that this news report is crammed full of factual errors, then perhaps it isn't obvious that what I said may have been completely misquoted? After all, the guy almost had me describing a new type of "crocodile antibodies"! This was "quoted" from a phone interview where I could hear the journalist typing in the background, so it's hardly a direct quote. The only part I definitely said word for word was the "gun to the head" line.
        And I'm not Australian, by the way (not yet at least) so I have no idea how to operate a sheep dip.
        Yes, we did discover an antimicrobial peptide (probably a defensin) several years ago. This is a continuation of that research.

        Adam Britton
        • It's no fun aimlessly ranting on Slashdot if the experts involved are going to come along and correct us. Please move along and allow us to go back to explaining why you're wrong, thanks.
        • by bcwengerter ( 416056 ) on Wednesday August 17, 2005 @12:17PM (#13340007) Homepage

          I apologize if I'm being redundant, but as of the time I'm writing this, there are 442 comments when browsing at -1, so I can't guarantee that I haven't missed something.

          In any event, I thought it might be helpful to post a link on PubMed [nih.gov] to the abstract [nih.gov] of the journal article to which the author of the Reuters article seems to be referring. At least, it's coming from the same lab and institution with which Dr. Britton (on his site [crocodilian.com]) mentions having a collaboration. Any other references would be greatly appreciated.

          Here's the full text for those who are interested:

          1: Antiviral Res. 2005 Apr;66(1):35-8.

          Antiviral activity of serum from the American alligator (Alligator mississippiensis).

          Merchant ME, Pallansch M, Paulman RL, Wells JB, Nalca A, Ptak R.

          Department of Chemistry, McNeese State University, Box 90455, Lake Charles, LA 70609, USA. mmerchan@mcneese.edu

          Serum from wild alligators was collected and tested for antibiotic activity against three enveloped viruses using cell-based assays. Alligator serum demonstrated antiviral activities against human immunodeficiency virus type 1 (HIV-1; IC50=0.9%), West Nile virus (WNV; IC50=4.3%), and Herpes simplex virus type 1 (HSV-1; IC50=3.4%). The inhibitory concentration (IC50) is defined as the concentration of serum that inhibits 50% of viral activity. The antiviral effects of the alligator serum were difficult to evaluate at high concentrations due to the inherent toxicity to the mammalian cells used to assay viral activities. The TC50 (serum concentration that reduces cell viability to 50%) values for the serum in the HIV-1, WNV, and HSV-1 assays were 32.8, 36.3 and 39.1%, respectively. Heat-treated serum (56 degrees C, 30 min) displayed IC50 values of >50, 9.8 and 14.9% for HIV-1, WNV and HSV-1 viruses, respectively. In addition, the TC50 values using heat-treated serum were substantially elevated for all three assays, relative to untreated serum (47.3 to >50%). Alligator serum complement activity has been shown to be heat labile under these conditions. HIV-1 antiviral action was heat-sensitive, and thus possibly due to the action of serum complement, while the anti-WNV and anti-HSV-1 activities were not heat labile and thus probably not complement mediated.

          PMID: 15781130 [PubMed - indexed for MEDLINE]

    • by Gopal.V ( 532678 ) on Wednesday August 17, 2005 @05:04AM (#13337382) Homepage Journal
      > There are lots of known chemicals that kill HIV. The trick is finding one that leaves the patient alive.

      A study in 2000 proved that 3 South African prostitutes were resistant to HIV strains from the region. They also found a significant group of kenyan prostitutes with relative immunities to small doses of HIV virii. Interestingly as soon as the women started getting money from the researchers for co-operation with the studies, they lost their immunity [bbc.co.uk].

      Should it come as a surprise that the Human immunodeficency virus is killed by something in crocodile serum ?. There are things in the human blood stream which can kill off HIV, but most of us lack these mutated T-cells (which are killed off by the normal cells) in sufficent quantity to beat the infection completely.
    • by krayzkrok ( 889340 ) on Wednesday August 17, 2005 @10:44AM (#13339067) Homepage
      One final comment on this - I need to vent! Bear in mind that these news reports are *way* off the mark in their reporting. The vast majority simply copied the Reuters article and diluted the facts yet further.

      It was Reuters who picked up on the HIV aspect and blew it out of proportion. It was never the goal of the study to combat HIV - it was just an interesting test. They even managed to misquote me almost completely. The main focus has been the antibacterial properties of the blood.

      Also, the part about the immune system being "too powerful" is something they pulled out of their cloaca. We're quite aware, as scientists, that it's far too early to start talking about marketable antibacterial drugs. The various factors that provide crocs with their powerful immune systems may not have any safe human medical use whatsoever. The fact that they *could*, however, is obviously interesting, but too many people here are taking this dodgy news report too literally. Don't get me wrong - this is exciting stuff and it could have health benefits down the line, but I don't like seeing this work getting misrepresented like this.

      There are peer-reviewed papers out there (check Merchant, principal author) and this work is being written up at the moment (check Merchant and Britton). They'll be far more informative than anything you'll read in the paper.

      Incidentally, we can't submit this to Nature because back in 1998 we did a pilot study, the lid of which was blown off from an unexpected source in a fit of excitement! So it's far too late for that - croc's out of the bag, etc...

      Adam Britton
  • Quick! (Score:5, Funny)

    by nate nice ( 672391 ) on Wednesday August 17, 2005 @02:18AM (#13336949) Journal
    Invest in crocodiles!
  • What a hack (Score:5, Informative)

    by Stickerboy ( 61554 ) on Wednesday August 17, 2005 @02:18AM (#13336950) Homepage
    "The scientists hope to collect enough crocodile blood to isolate the powerful antibodies and eventually develop an antibiotic for use by humans."

    Antibiotics kill living bacteria. There isn't a single antibiotic that can disable a virus (like HIV), which isn't even alive.

    The scientists probably hope to use modified crocodile immunoglobulin the same way we use animal-developed immunoglobulin as a tetanus antitoxin for patients who haven't been immunized... kind of a booster shot for patients fighting an HIV infection. The problem with animal-developed antibodies is that the human body recognizes them as foreign, and soon starts to mount an immune response against them as well.

    • Re:What a hack (Score:3, Interesting)

      by altstadt ( 125250 )

      There isn't a single antibiotic that can disable a virus...

      This will come as a great surprise to the many people who have taken antiviral [google.ca] drugs and been cured of various viral diseases. I was cured of some strange recurrant yuppie flu [google.ca] using Acyclovir [google.ca]. Thank $DEITY that I had a GP who had trained as a pharmacist.

      I guess we can be pedantic and say that antibiotics and antivirals are not similar things, but as far as the patient is concerned they are.

      • Re:What a hack (Score:3, Insightful)

        by 91degrees ( 207121 )
        I guess we can be pedantic and say that antibiotics and antivirals are not similar things, but as far as the patient is concerned they are.

        It's not being pedantic though. We want to know what this does. Explaining how it deals with bacteria doesn't tell us a lot about how it deals with a virus.

        This is a technical site, with a lot of scientists. Even though the majority of readers specialise in Engineering and physics, there are quite a number of biologists, and many who have at least some education
      • CFS .vs. Acyclovir (Score:3, Insightful)

        by Macka ( 9388 )

        Huh? yuppie flu is just a fancy name for Chronic Fatigue Syndrome. Following your google search link, the first real site it found was wrongdiagnosis.com and this is what it has to say about CFS.

        There is no effective treatment for CFS

        It then goes on to advise taking steps to treat the symptoms of CFS as a way of improving life.

        Acyclovir (brand name Zovirax) is used to treat herpes infections.

        So you're trying to tell us that you were cured of a disease that as no known effective treatment by a herpes c

    • Re:What a hack (Score:3, Interesting)

      by strider44 ( 650833 )
      The problem with animal-developed antibodies is that the human body recognizes them as foreign, and soon starts to mount an immune response against them as well.

      I have little idea about this kind of stuff but will this matter? I've been taught that HIV/AIDS destroys the immune system.
      • Yes it Does Matter (Score:3, Informative)

        by BioCS.Nerd ( 847372 )

        It matters. When you inject a foreign protein (or most anything for that matter) in your body you mount a defense to it. This can lead to flu-like symptoms and flat out rejection of the treatment. Even when you have HIV your immune system is still kicking around albeit in a weaker state. The last thing you need is to deal with HIV and some foreign protein.

        What will probably happen with this knowledge, assume it's viable, is the generation of chimeric antibodies, i.e. those with human and non-human com

    • by Andy_R ( 114137 ) on Wednesday August 17, 2005 @06:51AM (#13337666) Homepage Journal
      "The scientists hope to collect enough crocodile blood..."

      Conversely, the crocodiles hope to collect large quantities of scientist blood...
  • by NoGuffCheck ( 746638 ) on Wednesday August 17, 2005 @02:19AM (#13336955)
    "CRIKEY MATE, wouldnt want a take a hit from one of those!"

    "See what the HIV does is just go, nene ne ne nene ne all about looking for its food. ne nene ne ne nene all day long BANG! fucken huge croc grabs him, drags him under, death roll. CHOMP CHOMP CHOMP end of story."

    If I wasnt married.
  • by larry bagina ( 561269 ) on Wednesday August 17, 2005 @02:19AM (#13336956) Journal
    I'll reserve a real judgement for when more information is published in Nature or Science, but it doesn't appear to be anything useful.

    The human immune system is fully capable of killing HIV. However (dumbed down enough for Reuters readers) HIV infects T4 Lymphocytes, so killing the virus means killing your own immune system, and you die of obscure diseases.

    The antibacterial angle sounds promising, though.

    • by Anonymous Coward
      How the hell is it promising ? HIV is a virus not a bacteria, antibiotics won't do shit against it. You need to kill CD4+ cells that harbor the virus but guess what Sherlock, they die in abot 1.5 days after infection anyway. And even if you figure out how to kill the cells you still don't know which ones to kill because memory T cell contain HIV in latent state ! Bwahahaha ! You better hope you got d32 mutation in your CCR5 receptors because crocodile 'serum' is a crock of shit
      • by Isldeur ( 125133 ) on Wednesday August 17, 2005 @07:02AM (#13337704)
        How the hell is it promising ? HIV is a virus not a bacteria, antibiotics won't do shit against it. You need to kill CD4+ cells that harbor the virus but guess what Sherlock, they die in abot 1.5 days after infection anyway. And even if you figure out how to kill the cells you still don't know which ones to kill because memory T cell contain HIV in latent state ! Bwahahaha ! You better hope you got d32 mutation in your CCR5 receptors because crocodile 'serum' is a crock of shit

        Look Stonehenge. The point, and reason it's promising, is that -somehow- the crocodile is able to fend off this virus. A complex biological system more similar to us than "chlorine bleach" (as some other erudite poster mentioned) can destroy this. I don't see what the problem is in understanding this. No, we're not marketing some immunoglobulin or antiviral yet, but how can this not be an important discovery? Most antibiotics/drugs come from plants or molds afterall.
    • by ultranova ( 717540 ) on Wednesday August 17, 2005 @05:02AM (#13337380)

      The human immune system is fully capable of killing HIV. However (dumbed down enough for Reuters readers) HIV infects T4 Lymphocytes, so killing the virus means killing your own immune system, and you die of obscure diseases.

      I might be wrong here, but I was under the impression that the human immunity system cannot kill HIV - otherwise it would simply kill it before it destroys all the T-cells, after which the bone marrow would produce new ones to replenish the supply.

      Human immunity system uses a kind of "smart bomb" tactic - it has marker cells, which release chemicals that stick to foreign objects (like viruses or bacteria), and devourer cells that will attack anything that is so marked. This system allows the immunity system to fight effectively without causing too much damage to the host body it is defending. Unfortunately, the marker chemicals need to be custom-tailored for any particular intruder, and this creates a lag between a marker cell noticing a foreign object and devourer cells destroying it (which is why you get sick, get better and then won't get the same sickness for a while - it takes a while to get enough marker chemicals to your bloodstream to mount an effective defense, but once it's there, it stays there at least a while).

      Unfortunately, this doesn't work well against HIV viruses, because they mutate their outer shells at such rabid pace that by the time the immunity system is geared to fight one generation, the next generation is already immune to it. HIV is a bit like a criminal that keeps changing disguises constantly - by the time the police force gets wanted posters of him in the latest disguise, he has already switched to a new one.

      An effective HIV medicine would not neccessarily need to kill HIV outright, it would just need to be able to stick to any HIV mutation and look like the marker chemical on the outside.

      Disclaimer: I'm not a biologist, virologist or a white blood cell, and therefore don't have any first-hand knowledge of human immunity system. All the claims in this post are my own and do not reflect the official position of my immunity system. This means that I could be completely wrong.

      • by Anonymous Coward on Wednesday August 17, 2005 @06:36AM (#13337631)
        The body CAN indeed kill HIV however it can't completely eredicate it. But it comes closer than you seem to think.

        When a person becomes infected with HIV, the amount of virus in the blood explodes - it goes from 0 zero copies per mL to several million copies per mL. This triggers an immune reaction (which is why a large percentage of patients get flu-like symptoms during the earliest stages of infection). But guess what, after a few additional more weeks the body has sort of taken control and the viral load drops so low that it is undetectable (and we can measure down to a few hundred copies per mL). The initial symptoms go away and for some period of time it may be impossible to give any direct evidence of the infection. Note that this is what occurs with treatment of any kind!
        HIV-tests detect the body's own antibodies against HIV but it may not be possible to detect the virus itself.

        Replication must however continue to occur on a low level because over the years most HIV patients experience a steady decline of CD4+ cells, the cells that HIV most frequently infects. After some time this decline starts to accelerate until the CD4+ count is so low the patient gets sick from all kinds of diseases.

        It is not known exactly what is the cause of this decline. It seems weird that the body can fight off the virus at millions of copies per mL without suffering much damage while the last bit of replication (probably caused by latently infected cells) is so damaging. One thing that is known is that the CD4+ cells do not die as a direct result of being infected with HIV. In fact it is a very small percentage of CD4+ cells that are infected at any given time. CD4+ cells may be dying because of apoptosis (cellular suicide) triggered in some way by chemicals in the blood stream or actions of other cells infected with HIV. The hole flow from HIV infection to AIDS also involves certian mutations taking place in the virus' gene. It may be these mutation that causes the accelerated decline but the causation may also be the other way around.
      • You may not be a biologist but your post was put together coherently enough for me to read it because you made it sound so interesting. I hope you get modded as appropreiate.
  • by Anonymous Coward on Wednesday August 17, 2005 @02:21AM (#13336967)
    Ich bin Schnappie, das kleine HIV-curing krokodil?
    • Re:Sing with me (Score:3, Informative)

      by Tmack ( 593755 )
      Too many people probly dont know the reference, so here is a link to all you need to know...
      Schnappie, das kleine Krokodil [schnappi.tv]
      Amusing, even if you dont know german, more so if you do.

      Brief descript for the lazy non-clicker types: German kids webpage (tv show too?) with an animated crocodile as the main character that likes to sing/dance/etc. Think of an animated version of Barney the purple dinosaur where barney is a little green croc instead.

      tm

  • by Anakron ( 899671 ) on Wednesday August 17, 2005 @02:22AM (#13336971)
    It's like putting a gun to the head of the bacteria and pulling the trigger
    Of course, they first make the bacteria an offer they can't refuse.
  • Crocodile Spam (Score:5, Interesting)

    by XNormal ( 8617 ) on Wednesday August 17, 2005 @02:46AM (#13337054) Homepage
    Spammers are already promoting a product called "The Antidote" supposedly produced from crocodile blood. With these news I think it will get worse.

    Here is the FDA's warning [fda.gov].

    The worst thing about it is to realize that some desperate people are actually falling for this scam.
    • Re:Crocodile Spam (Score:5, Informative)

      by krayzkrok ( 889340 ) on Wednesday August 17, 2005 @07:00AM (#13337697) Homepage
      This scam fed off our initial pilot study findings, back in 1998. There was worldwide media exposure at the time because of the demonstrated ability of the croc serum against antibiotic-resistant bacteria (S. aureus). They used this media coverage in a weak attempt to add credibility to their product.

      Yes, we have tried suing them (mainly for defamation, because they claim we endorse this crap) but it's very difficult to sue companies that apparently don't exist.

      Adam Britton
  • by multiplexo ( 27356 ) * on Wednesday August 17, 2005 @02:59AM (#13337098) Journal
    there was a discovery [indystar.com] recently that Valproic acid [mentalhealth.com], a commonly used anti-convulsant drug can cause cells that are infected with dormant HIV to express the virus, which then alerts the immune system which then kills the cells. If this works out it will be a major advance as one of the problems with HIV now is that it can go dormant for long periods of time, especially with the new HIV drugs that are available and then flare up again. If you force the virus to express itself the immune system kills the cells it has infected. There is a possibility with this treatment that the body could be cleansed of HIV. If this works out there will still be the hard work of developing therapies that can be afforded in the third world, but it's a promising start.

  • by fyoder ( 857358 ) on Wednesday August 17, 2005 @03:39AM (#13337199) Homepage Journal
    Those who like to have unprotected sex can restrict themselves to crocodiles with some assurance of safety. Crocs are unlikely to have AIDS or to contract it.
  • by krayzkrok ( 889340 ) on Wednesday August 17, 2005 @06:53AM (#13337678) Homepage
    Ho, never thought I'd be the subject of a Slashdot news report.
    Time to clarify things.
    TFA contains a number of errors. First the statement I made about HIV is true, but as others have pointed out it does not mean we've found the cure for AIDS. It simply means that we've compared alligator serum and human serum and found the former significantly more effective at killing the HIV virus than human serum. It was intended to illustrate the overall efficacy of the crocodile / alligator immune system, that was all.
    Second, these are not antibodies. Croc immune system works primarily through the innate or complement system, which does not involve antibodies. It's a simpler and more primitive immune response than the adaptive immune system that is key for mammals, but the advantage is that it's very direct and hence difficult for bacteria etc to evolve resistance to. It's "primitive" nature may be behind its effectiveness.
    The main finding here is that the alligator / crocodile immune system is far more effective at killing a wider range of bacteria (gram +ve and gram -ve), viruses and fungi than our own immune system. When you've evolved over 235 million years, and your daily social behaviour involves biting limbs off other crocs, you need a good immune system! It clearly has potential medical implications down the line, but that's a long way off yet. First we have to fully understand what makes croc immunity tick. We are still trying to purify a protein which we believe is an antimicrobial peptide, but hopefully that will happen very soon after this recent work.
    Eventually if anything does come of this, and we can isolate a "factor" that has human medical implications (and is safe for humans, unlike the far more effective chlorine bleach) it would indeed be synthesised. Adam Britton
    • It's a simpler and more primitive immune response than the adaptive immune system that is key for mammals, but the advantage is that it's very direct and hence difficult for bacteria etc to evolve resistance to. It's "primitive" nature may be behind its effectiveness.

      So if their immune system is more "primitive", is it in some way inferior? The reason I ask is, we usually assume that evolution doesn't add complexity to organisms to make them weaker with absolutely no benefit (which I know is debatable, but

      • by krayzkrok ( 889340 ) on Wednesday August 17, 2005 @10:28AM (#13338901) Homepage
        This isn't my theory, and I can't seem to pull the appropriate citation up for you, but the gist of the paper was that the innate immune system is very much a secondary response in humans and hence has always been viewed as "primitive" (hence the quotes). Reptiles (and some other groups including fish) never developed a particularly effective adaptive immune response like mammals, but instead their innate immune system naturally evolved over time to become more effective than the innate system in mammals. The main advantage of the innate response seems to be its non-specificity. The results we're seeing in alligators, crocs, sharks etc seem to bear this out to a degree. Inferior? There's no such thing, in my opinion - each system is well-adapted for each user even though it's never perfect. If it was we'd never fall ill. So perhaps we can cheat a little and steal the good bits from our (very) distant relatives...?

        Adam Britton
      • by 3-State Bit ( 225583 ) on Wednesday August 17, 2005 @11:04AM (#13339243)
        For a citation that has probably very much relevance to the researcher's phrase "adaptive immune system (like mammals)" in response to your post, look at the research behind a Nobel Prize given not long ago for "The Generative Grammar of the Immune System". [google.com].
  • by Stephen H-B ( 771203 ) <.sjholmesbrown. .at. .gmail.com.> on Wednesday August 17, 2005 @06:59AM (#13337693) Homepage
    In the lab where I'm a student, we work with a class of small proteins called 'defensins'. These proteins are involved in what is called the 'innate' immune response of animals, as opposed to the 'adaptive' immune response, which is where antibodies come in.

    These defensins have been found in many different organisms, from fish to plants to humans. I think this article is actually talking about an innate immune response, since adaptive immunity requires previous exposure to a pathogen, leading to production of specific antibodies. Defensins have a fairly broad anti-microbial activity, and some have already been isolated and shown to be effective against gram-positive and -negative bacteria, fungi, viruses and insects (no one defensin acts against all these, though)

    • by krayzkrok ( 889340 ) on Wednesday August 17, 2005 @07:14AM (#13337742) Homepage
      Correct, this is what we're talking about primarily. The news article was wildly inaccurate and embarrassing to read quite frankly!

      We don't talk about defensins because we're not sure yet that defensins are involved. We suspect they are, but until we purify and sequence the proteins we're looking at we can't be sure. Hopefully this is only weeks away.

  • by icepick72 ( 834363 ) on Wednesday August 17, 2005 @08:39AM (#13338056)
    From article: For the past 10 days Britton and Merchant have been carefully collecting blood from wild and captive crocodiles

    Really, is there any other way.

All this wheeling and dealing around, why, it isn't for money, it's for fun. Money's just the way we keep score. -- Henry Tyroon

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