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Chimps, AIDS, And Immunity
Posted by
Hemos
on Fri Aug 30, 2002 01:03 PM
from the outlasting-it dept.
from the outlasting-it dept.
Anonymous Coward writes "Researchers at the Biomedical Primate Research Center in The Netherlands have come up with a theory as to why modern chimps don't develop AIDS and its variants.
The chimps in the study were found to share a usually uniform cluster of genes in the area that controls their immune systems' defenses against disease. This lack of genetic diversity suggests that a lethal sickness attacked chimps in the distant past.
The theory postulates that approximately 2 million years ago an AIDS-like epidemic wiped out a large portion of the chimpanzee population. Those that survived developed an immunity to AIDS and its variants.
If this theory holds true it may explain why some humans who are repeatedly exposed to HIV don't get sick."
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SIV? (Score:3, Interesting)
"IV). From what I've read in the past, they are remarkably similar...
Re:SIV? (Score:2)
Re:SIV? (Score:2)
(emphasis mine). They don't actually say SIV, but it is quite clearly what they are talking about.
Practicing animal husbandry? (Score:2, Funny)
How Does It Explain Human Immunity? (Score:3, Interesting)
Those that survived developed an immunity to AIDS and its variants. If this theory holds true it may explain why some humans who are repeatedly exposed to HIV don't get sick
What does one have to do with the other? Besides the fact that there is a quote in the article that states the only way this has a bearing on human immunity is if the submitter is suggesting that those humans with AIDS immunity are evolved from chimps two million years ago which seems highly unlikely.
Re:How Does It Explain Human Immunity? (Score:2, Informative)
Re:How Does It Explain Human Immunity? (Score:2)
Re:How Does It Explain Human Immunity? (Score:2)
First of all, we share roughly 97% of our DNS with chimpanzees
Actually I don't think we share any of our DNS servers with chimps, unless you count MCSEs.
haven't had a catastrophic disease like HIC deicmate our population
I was picturing an entire population of humans dying of HICups. *HIC*....*HIC*....*HIC*...<collapses on the floor>, "Well Billy Bob, it looks like anuther one died of that ach eye see virus."
Sorry, I know HIV is not a laughing matter, but I found the mental picture of the 'HIC' virus quite entertaining and thought I'd share. Hmmm, maybe I shouldn't have.
Sharing DNS with chimpanzees (Score:5, Funny)
Hey, now, that may be true, but I don't think ICANN would appreciate you categorizing them thusly.
Parent
Re:How Does It Explain Human Immunity? (Score:3, Insightful)
It's relevant by implication only. HIV can do to humanity what the unnamed-disease did to the chimps two million years ago -- wipe out most of us except the few who have a natural genetic resitance to the virus. Then, two million years from now, someone will comment on how our "immunity genes" are very similar.
Light on Details, of course... (Score:2)
AIDS, mortality, and timing. (Score:5, Insightful)
I was a little young, so I didn't realize it until much later, but this was a pretty "in your face" demonstration of how timing, in the sense of where you are in the course of human technological development can have a serious impact on your expected longevity.
There are, of course, the obvious facts that a long, long time ago your life-expectancy would be 30 years, whereas now (depending on where you live) it might be near 80. This is a development over thousands of years, though.
It's a bit shocking to think that if my uncle had developed his complications a few years later he might still be around today. I've always taken solace in the fact that the same could be said of my father's friends who were drafted for Vietnam, or my grandfather's friends who died in Korea, etc.
Illnesses seem a bit "different", though. Wars are arguably preventable, illnesses kinda just happen. I'm hoping and hoping that startling achievements in fighting "natural causes" will reach some sort of threshold where we might be expected to live for a ridiculously long time.
Longevity treatments, anyone?
Re:AIDS, mortality, and timing. (Score:4, Insightful)
Meaning absolutely no disrespect to either you or your late uncle, AIDS does not "kinda just happen"; nor, for that matter, do many other illnesses.
The vast majority of AIDS cases stem from sexual activity and shared needles. It is conceivable that, given enough education, focus and effort, AIDS could be effectively eradicated in the span of a couple of generations with technology that is currently available. AIDS is not something that just kinda turns up in your system one fine morning; is an epidemic that can be effectively prevented with some very basic safeguards.
Again, I say this neither to inflict pain nor insult on you and your family. Rather, I say this to combat the notion that AIDS "just kinda happens", a view that will cause more harm than comfort in the long run.
Parent
Re:AIDS, mortality, and timing. (Score:5, Interesting)
If the latency period of HIV is up to ten years (which is the last I've heard of it), and if my uncle died in 1992 (which he did), then if we also give a few years of wasting away (I don't know when he first developed symptoms), then he could have been infected way back in the 70's.
There was little to no information about HIV at the time. Think about all of the people who were infected by blood transfusions and whatnot. We only know that these things need to be checked out now. For my uncle, who probably got it from sex, and for blood transfusion victims, the disease basically "did just happen".
The only way it could have been prevented, because the vector was unknown, and, actually the disease was practically unknown, would have been to not engage in sex. Hah.
Parent
Re:AIDS, mortality, and timing. (Score:2)
I posted out of frustration at the fact that the AIDS epidemic is showing every sign of spiralling out of control, and that this epidemic will be aided every step of the way by undereducation, religious agendas, poverty, politics, and ignorance.
Re:AIDS, mortality, and timing. (Score:2)
Re:AIDS, mortality, and timing. (Score:3, Informative)
Rape is a huge problem in Africa, especially in the kwa-Zulu Natal area that has been described as the 'epicenter of AIDS' now that Uganda has gotten things under control. AIDS really can just kinda turn up in your system one morning without you having any choice in the matter - for many people, it's often not as simple as wearing a condom and not sharing a needle.
AIDS contracted through other means. (Score:4, Insightful)
AIDS/HIV "just happened" to many people who received blood and blood products in medical procedures. Especially hard hit were those with hemophilia. They were stricken at a horrible rate.
Isaac Asimov's 1992 death from heart and kidney failure was a consequence of AIDS contracted from a transfusion of tainted blood during his December 1983 triple-bypass operation.
Babies are born with it, rape victims contract it, and people getting organ transplants are infected by it.
Let us not stigmatize everyone who is suffering with, or has died from, this horrible disease by painting with too wide a brush and categorizing the victims as drug addicts and people who engage in unsafe sex.
Parent
Re:AIDS, mortality, and timing. (Score:2)
If they could be made even smaller, they could be used to extend telomeres (sp?) on chromosomes, so that aging could effectively be halted.
Put enough of these in one's bloodstream, load them up with a few communal behaviors (CLOT@DISMEMBERMENT), and a human being could be made pretty damn near immortal.
The only real problems then would be disorders we truly didn't understand, and thus a fine degree of control would be irrelevant.
Proviso: I'm a geek, not a doctor. Commence the hole-punching in these ideas...
Life expectancy (Score:4, Insightful)
I don't dispute your basic statement that average life expectancy 200-300 years ago was about 30 years. However, you need to look at what that number means.
200-300 years ago a *lot* of people died of childhood diseases. Once you made it past about age 15, you had a reasonable chance of living to see 50, and 70 wasn't completely unreasonable for the non-poor.
The "average life expectancy of 30 years" combined with "most people that live past 18 live to see 50" means that a good third of all people never lived through childhood, and most of these died before age 9.
A large percentage of women died in childbirth also. (It's amazing how that percentage dropped drastically when doctors simply started washing their hands.)
When 1/3 of your population lives to average 5, and 1/3 of your population lives to average about 35 (those childbirth deaths for women pull their average down) and 1/3 of the population lives to about 55...
Gives you an average life expectancy of about 30.
But if you lived to see 15, you had a reasonable chance of living to see 50 and beyond.
We haven't really done too much to extend life. Our average life expectancy has gone up so drastically in the last 100 years because we have beaten most childhood diseases, and reduced the childbirth-related deaths in women.
Lies, damn lies, and statistics.
It's not so much that I object to people lying with statistics... just be aware when you are doing it, okay?
Parent
Re:Life expectancy (Score:3, Funny)
Re:AIDS, mortality, and timing. (Score:2)
A good example of this is cancer. Cancer was uncommon in the 19th. century. By the end of the 20th. century it was the primary killer in Western countries.
Was there a sudden upsurge in cancer? Did more virulent "strains" suddenly appear? No. It simpler. Back in the 1800's few people died of cancer because most of the population died of other diseases. Cancer is (with some exceptions) a disease of old age. If you die of tuberculosis in your early twenties as millions did back then, you won't survive to die of the cancer that would have killed you when you hit 60.
Many of these "new" diseases are more prominent now because we have eliminated so many other diseases that used to cull the herd of mankind.
Of course there are exceptions. HIV/AIDS may be one - it appears to have evolved into a mass-transmitable and often fatal disease in recent memory.
unusually uniform cluster of genes (Score:2, Informative)
Rather simple (Score:5, Informative)
It is actually rather simple why certain people can be repeatedly exposed to HIV and not become productively infected. HIV requires its target cells have two cell surface proteins in order to infect it. One is the basic CD4 T cell receptor. The other is one of two different types of chemokine receptor. There is the CXCR4 and CCR5 receptors. The names derive from a common amino acid motif found in these receptors in most people: for CXCR4 it is cysteine-any amino-cysteine-arginine. For CCR5 it is cysteine-cysteine-arginine. Most of the people who appear immune to the infection contain a mutation in the CCR5 receptor (I'm not familiar with the CXCR4 receptor vis a vis mutations and infection resistance). Thus, HIV can bind to CD4 but because of the mutation in CCR5 it cannot complete the process and fuse with the cell. No fusion, no infection.
This common form of resistance doesn't require any cluster of genes nor any mysterious genetic variation or evolutionary alteration.
Re:Rather simple (Score:2, Funny)
That CCR5 is like the 'cells' sendmail?! Hot DAMN!
Btw, can you give me the DNA diff so I can patch it? Thanks
Re:Rather simple (Score:2, Informative)
Virology is admittedly not my area of research, but I'd think that there seem to be two divergent opinions here on simian resistance. Anyone here working in the area care to explain the (seeming) contradiction?
Re:Rather simple (Score:2)
Yes, as a simple mutation it has a potential contribution to evolution of humans. If HIV were to _really_ get widespread and kill lots of people to the point that most remaining people were mutant CCR5 carriers, then they would be the ones to most successfully pass on their genes to the next generation and future humans would be immune...evolution in action.
I simply meant that I don't think one HAS to look at a complex cluster of genes in simians and infer that this is the sort of thing that would have to happen to humans for them to evolve immunity like the simians. For us, all we need in this case is a relatively minor variation in one protein (two if you really want to get decent protection: CCR5 and CXCR4 - and hope that the mutations dont screw something else up in the process of giving you immunity to one virus).
Subject test group? (Score:5, Funny)
Limited genetic diversity (Score:2)
Perhaps some misunderstanding... (Score:5, Informative)
One thing I noticed... (Score:3, Insightful)
The end quote of the article says If the theory of an ancient chimp epidemic would hold true for humans, he said, "the implications are pretty scary."
Just how are the implications pretty scary? Chimps weren't doing anything to stop the spread of the disease, we are. We're educating people and trying to encourage safer practices. The chimps who were almost wiped out didn't have a 7th grade health class where they learned that condoms can significantly lower their risks of contracting SIV. We do. The places where HIV has become an epidemic are the ones where there aren't such classes. They need them.
I worked at the NCI (Score:2, Informative)
Re:I worked at the NCI (Score:4, Interesting)
What else does this gene impact? Obviously it has been changed naturally in some people, so it may not have that much of an impact...
Parent
I propose a trade? (Score:2)
I say we trade the language [bbc.co.uk] gene [nature.com] for their AIDS immunity gene.
It would be beneficial to both species. Well, the language gene is arguably more trouble than it's worth, but these monkeys are dumb and will probably fall for it if we throw in a few extra bananas to sweeten the deal.
4-7 millions years ago. not 2. (Score:2, Informative)
2 million years ago, something happening to the ancestor of modern Chimpanzee isn't going to affect us, unless our ancestors were also involved.
duh! i wish these people would do more research before making such crap as 'it may explain why some humans who are repeatedly exposed to HIV don't get sick.'
Re:4-7 millions years ago. not 2. (Score:2, Insightful)
The group posits that, because you have a very specific loss of variability in an area that controls the molecules HIV & similar retroviruses use for infection, and chimps are immune to these viruses, there may originally have been a varied population of chimps (like humans) that were culled down to a very small population that had immunity (and this current, limited genetic make-up).
Punctuated Equilibrium (Score:3, Interesting)
Bubonic plague link (Score:2)
When the "black death" hit Europe, it killed as much as 1/3 of the population. The survivors likely had a genetic advantage that helped them survive. This same genetic resistance which was an advantage 700 years ago appears to be valuable today. Sub-saharan Africa did not suffer the same rampant spread of the plague, and thus those genes were less likely to be preserved in the general population.
QUESTION FOR THE BIOCHEMISTS (Score:3, Interesting)
How many strains of HIV are there (or that we know about), and what differences are there in their vectors, mechanisms, and effects?
Secondly, has there been any evidence that once infected with one strain, that there is a resistance to a new one? For example, if a Chimp is infected with SIV, is it less likely to become infected with HIV (or vice versa)?
Just wondering if any evidence has cropped up to suggest there is promise in William Gibson's "benign HIV+" idea (I think it was in Virtual Light).
Re:QUESTION FOR THE BIOCHEMISTS (Score:3, Informative)
I'm not a biochemist, but I can answer the second one: Sometimes. Gene mutations are belived to be random. The chimp doesn't have a SIV specific gene, it has a gene that causes certian types of protiens. The protien then allows certian immunities. It might happen that the gene only affects SIV, more likely it affects several things, which might or might not include HIV.
One of the early vacinations for small pox was bassed on cow pox, once infected by cow pox you were immune to small pox. So yes, one infection can make you resistant to a different one. However there are many different viriues. Most people get the flu every year, and each time they get one strain they become resistant to that and several other, however appearently not the one that strikes the next year.
There are too many random factors in immunities and genetics to really answer your second question, but I tried.
of course! (Score:4, Funny)
They are in fact shaved monkeys, and not people after all?
not scary at all (Score:4, Insightful)
I don't see anything particularly scary about it: the fact that we have the data from chimps may well let us develop better drugs.
If the biologists are "scared" by the fact that 90% of a population may have been wiped out by a virus--well, welcome to the real world. Those things happen to real world species. Humans are particularly susceptible because of travel and high population densities, but we also have a public health system going for us.
Note, incidentally, that infectious mononucleosis probably was also devastating for human ancestors--very lethal and very easy to transmit. Today, it is a harmless disease only because of an odd quirk of the virus and the human immune system.
you place great faith in the abilities of humans (Score:3, Interesting)
(as it's friday afternoon, I am kinda lazy to provide links, but all should be found on the web here or another)
1) HIV is spreading, and doing so at a faster rate than before. Partly it's because of people are getting the idea that the "cocktail treatment" has effect -- but the truth is that it's not nearly that effective for the amount of casual sex people tend to want to carry.
2) HIV mutates faster than we can come up with drugs for them. some strains, in fact, was resistant / became resistant (through mutation, presumably) even before a vaccine / treatment was made into mass production
3) many leads for possible cure has turned out to be dead-ends. I am sure many have heard about the people (select few, 5% or so?) who contract HIV but does not actually exhibit the symptoms of AIDS for a long time (15-20 years) -- Eventually it turns out that these are people who simply had a combination of good immune system and a "weak" strain of HIV. they eventually got AIDS.
4) vaccination requires a response from the immune system toward an agent (mutated, harmless version of HIV, for example) -- however this response we want to elicit from the immune system is *not a natural one*, meaning that it is not one that occurs, or have been observerd to occur (through much searching, as you could imagine) natually, and worse yet, *MAY NOT EXIST*.
there are a couple others; but unless much more breakthrough level results are obtained, soon, the AIDS epidemic will become a catastrophic event that will have no less impact on the world today as the Black Plague had in times past.
Re:Cure with Chimps? (Score:2)
Re:My question is... (Score:2)
Re:My question is... (Score:2)
This theory could explain it....
Dickey Chaney (Score:2)
No, but Dick "Stalin in Training" Chaney sure can, and since he's been bending most of America over about a year now, there's a good chance the rest of us over here will bet it too. Our only hope is that he keeps reaming us out with the erstwhile Bill of Rights, rather than his own appendage, but I don't think thats something any of us can count on.
Re:Where does that come from? (Score:2)
I cant give you the details but I remember reading an article about it in "New Scientist" so its not just an urban legend. I read it in the print edition but you might be able to find it on their website.
Re:Deusberg (Score:2)
Based on his theory, Duesberg predicted that the drugs developed to treat HIV would do more harm than good. But in reality, they dramatically reduced AIDS deaths.
Re:Deusberg (Score:2)
If you had READ the site he says that people in SA show a lot of AID like symptons like diarehha, weight loss, etc... b/c they are malnurished and don't live in the most sanitary of places.
One of the more intersting things that he says is the way the U.S. classifies people as having AIDs. For example if you have TB, then you have TB. If you have TB + HIV antibodies then you have AIDS.
Is this guy a crackpot? Who knows(he has articles from nobel prize winners on his site), but in any case it's an interesting read and makes you wonder about what the media has been feeding us for years about the disease.