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

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.

[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.

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...

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.