Chimps, AIDS, And Immunity

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."

Comments

SIV?

[Maditude]

Anyone know why the article doesn't mention anything about SIV (Simian "IV" instead of Human
"IV). From what I've read in the past, they are remarkably similar...

How Does It Explain Human Immunity?

[Carnage4Life]

From the Slashdot blurb:

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

He also said there is no definitive proof linking specific genes with resistance to AIDS in either chimpanzees or humans,

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?

[mshiltonj]

...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.

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.

AIDS, mortality, and timing.

[Buck2]

My uncle died of AIDS (or complications thereof) just a few years before the cocktail treatments started showing efficacy in extending HIV+ person's lifespans.

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.

[American AC in Paris]

Illnesses seem a bit "different", though. Wars are arguably preventable, illnesses kinda just happen.

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.

Re:AIDS, mortality, and timing.

[Buck2]

Actually, you are probably speaking from a position that benefits from hindsight.

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.

Re:AIDS, mortality, and timing.

[Mr.Ned]

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.

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.

Rather simple

[praedor]

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.

Subject test group?

[broken.data]

I completely misread the last line as why some humans who are repeatedly exposed to HIV don't get sex. We are talking about code-monkeys, right?

Perhaps some misunderstanding...

[broken_down_programm]

"Those that survived developed an immunity to AIDS and its variants. " ...Uh, IANA genetecist, but I THINK the way it works is that those that ALREADY had the peculiar genetic combination that would equip them to survive SIV where the ones that SURVIVED. Through their offspring this combination came to prevail in the population today...

One thing I noticed...

[Liora]

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.

Re:I worked at the NCI

[anzha]

Ethical questions aside, So how difficult would it be to purposefully change this one gene in an embryo?

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...

Sharing DNS with chimpanzees

[Junior J. Junior III]

First of all, we share roughly 97% of our DNS with chimpanzees.

Hey, now, that may be true, but I don't think ICANN would appreciate you categorizing them thusly.

Punctuated Equilibrium

[theCat]

That's what Niles Eldredge and Stephen Jay Gould called it. Basically, evolution by totally getting your ass kicked. No, it doesn't really apply to humans, we're outside the flow of evolution for all practical purposes. We evolve via understanding, not genetics.

QUESTION FOR THE BIOCHEMISTS

[ArcSecond]

Two questions:

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

[bluGill]

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!

[Scrameustache]

If this theory holds true it may explain why some humans who are repeatedly exposed to HIV don't get sick."

They are in fact shaved monkeys, and not people after all?

not scary at all

[g4dget]

If the theory of an ancient chimp epidemic would hold true for humans, he said, "the implications are pretty scary."

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.

Life expectancy

[TFloore]

Learn something about how statistics are collected and how to apply them.

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? :)

Re:Life expectancy

[yobbo]

If only we had made the doctors of 300 years ago vote in the hand washing polls on slashdot, we could've exposed them for the dirty buggers that they were and saved many lives.

AIDS contracted through other means.

[fmaxwell]

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.

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.

you place great faith in the abilities of humans

[lingqi]

The implications are scary because several things:

(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.