Engineered Stem Cells Seek out and Kill HIV in Living Mice

reply to post by Sinny

I was urged to post a reply to this thread because I work with the lab that published this data, although I work on other anti-HIV genes/genetics manipulations of "stem cells" in hopes of an engineered cure for HIV disease. Hopefully, it doesn’t turn into a dissertation.

First, and the most obvious question for scientists, how does this specific treatment engineered to make super killer T cells get around the fact that T cells are killed by HIV? This is actually not a trivial question. While everyone knows that HIV preferentially infects CD4-expressing cells (CD4 is a protein on the surface of T cells and macrophages), all T cells begin as CD4-expressing cells in the thymus as they develop. And as such, thymocytes (young and immature T cells) are exquisitely sensitive to HIV. This is part of the reason HIV infected individuals cannot recover their CD4 T cell compartment and succumb to AIDS. Honestly, it is such a valid point, that even most (dare I say all) of the researchers involved in this study didn't think it would work. But we continue for a number of reasons:

(1) We never expected gene therapy approaches towards HIV would work with one candidate anti-HIV gene. Yes, because the virus mutates at rates faster than you can barely comprehend! That's why we are working full speed on half a dozen other anti-HV gene therapy candidates. We hope that as we determine which anti-HIV candidates work individually, we can begin to create combinations containing more than one anti-HIV gene in hopes of combating the high mutation rate. We have been working closely with mathematicians who have modeled that depending on specifically how we inhibit the virus, we will likely only need two or three anti-HIV genes.

(2) These are cutting edge, never been done before, "proof of principle studies." Let me expound on this topic and hopefully answer another's question in the process...

Remember I said HIV preferentially infects CD4 T cells? These are the helper T cells someone posted about earlier. Meanwhile, the killer T cells, once they are mature, don’t express CD4 anymore (making them now unable to be infected be HIV) and now express the marker CD8 – so we call them CD8 killer or cytotoxic T cells. These cells have a very cool, very, very, very, very, very, very specific protein that enables them to attack only one specific target. So, for example when you get the flu, you generate CD8 cytotoxic T cells that can specifically recognize the flu, but only the flu. Not HIV, not staph, not diptheria, not whooping cough. Only the flu. And then these killer cells can kill other cells that are infected with the flu. I wont get into how they recognize flu-infected cells, they just do and they kill them. And then some of these killer cells stick around for decades as memory CD8 T cells - just in case you ever get the flu again, they are there to bounce back and kill it! We also have memory CD4 T cells and long lived B cells that make antibodies (plasma cells) to fight the flu. But it’s important to understand that the role of cytotoxic T cells is to kill infected cells, not the virus itself. That’s the antibody’s job. Antibodies are very good at neutralizing viruses and bacteria. So again, killer T cells kill cells, not the virus. Which is a reason the authors of this study refuse to say this treatment could cure HIV. It can only cut down on the number of infected cells.

reply to post by Sinny


So, how do we generate HIV-specific killer T cells in the first place? Well, all proteins are encoded for by a gene (one gene, one protein) and once you know the gene, you can clone it out. Cloning a gene is a lab term for cutting the gene out of the DNA in one cell and pasting it into the DNA of another cell. So we determined the gene that encodes the protein that is specific to killing HIV cells - in this case, it’s called a T cell receptor gene. Every single T cell in the body has it’s own unique T cell receptor. It’s something fascinating about the immune system. While we have been taught the dogma that every somatic cell has the exact same DNA for one person, T and B cells are the exceptions to that rule. When a T cell’s T cells receptor kinda sorta recognizes its specific target (this recognition is purely random based on chemical affinities), this recognition causes the single T cell to divide rapidly, proliferating more and more of these specific T cells. During that proliferation process, the T cell receptor gene undergoes massive mutations. Some of these mutations make the T cell receptor recognize its target better and some worse. For the cells whose T cell receptor recognizes its target even better, those cells expand even more. During a strong viral infection like the flu, 25% of your immune cells can be one type of T cells! And we take your blood and dilute it down until we can find just one of those T cells and then we can clone out that T cell receptor.

Which is what the authors of this study did with HIV. The difference and part of what makes this study so amazing is that while the flu generates a very, very strong immune response, HIV does not. This is partly because HIV hides the parts of it that are strongly immunogenic (meaning the parts of it that would be capable to generating a strong immune response). So the authors of this study had to scan hundreds and hundreds of T cell receptors to find one that was quite strong against HIV and then clone it out. While this was bound to happen in time, I can’t stress enough the amount of time and effort dozens of scientists spent and the nearly dozen years it took them to do this!

So, then to take this cloned T cell receptor that is incredibly rare with respect to killing HIV-infected cells, not to mention a genetically complicated piece of DNA requiring proper subunits etc, and cloning it into anything, much less a stem cell, was pretty damn cool! In the first study published, they expressed this rare, unique, effective, complicated gene in an adult T cell and got it working! But to do the same thing in a “stem cell” (more on that later), and despite the genetic modification, was able to see that “stem cell” turn into a proper T cell, and then that this T cell was indeed able to kill HIV-infected cells, that’s what we call proof of principle.

Wondered when they were going to do something useful with stem cells.

They have also developed an AIDS vaccine.
AIDS vaccine tested on humans

reply to post by Sinny

On to how we study HIV infection in mice:

I've been doing this every day for over two years and I'm still amazed at what we actually do: we take severely immune compromised mice (we call these mice NSG for short but they basically contain a variety of mutations that almost completely eliminate their immune systems - we breed and/or buy them from Jackson Labs: jaxmice.jax.org...) and give them human immune systems because, as someone pointed out earlier, no, mice cannot be infected with HIV. The lack of a small animal model for HIV research has severely held back progress on the disease. However, as the use and experience with humanized mice has improved over the last couple decades, the model has become quite useful for HIV research and I expect you'll see more and more papers on scientific advances leading towards a cure for HIV. But I digress. The specific mouse strain and process for humanization varies and we have entire international conferences devoted to trying to clarify this even among the scientists that use it every day. For this specific study, we used the NSG mice (as opposed to NOD/SCID or Rag2-/- etc). These mice undergo a theoretically simple/technically challenging survival surgery, in which they receive fetal human thymus and liver and modified "stem cells."

So I know I just said some very disconcerting things. First off, "fetal?" Yes. I was pretty surprised at first, as well. And, fetal tissue is just as hard to come by as you might think. We have relationships with hospitals and clinics. Patients must be undergoing elective abortions and they must sign a consent/release form in order to obtain the tissue. Then someone has to procure the proper the tissues, also not an easy job. Because the human immune system begins in the fetal liver and fetal thymus, we take those tissues.

From the fetal liver, we isolate what are called CD34+ cells. These are hematopoietic (that's just scientist speak for blood) progenitor cells. We don't actually call them stem cells in the lab because they are not true stem cells. In fact, they are so far away from embryonic stem cells, they are considered "adult stem cells," which are scientifically called progenitor cells instead of stem cells. These CD34+ cells have the potential to become every single cell type in our blood, which makes them great cells to study gene therapy for all blood diseases like sickle cell anemia, hemoglobin disorders and HIV! So we isolate the CD34+ cells and genetically modify them so that they contain the anti-HIV genes we want to express.

To create the humanized mice, we surgically implant a teeny, tiny, itsby, bitsy piece of the fetal liver and thymus under the kidney capsule of the mouse. Yep. And I was always in awe of human baby/neonate surgeons. Imagine how much harder it is to perform a surgery on a mouse kidney. It is literally smaller than a kidney bean! So the mouse in under anesthesia, just like a human would be. We make a small incision, find the kidney and clamp it and the "kidney capsule" is the thin membrane that encircles the kidney. It's literally less than a hair wide! We take our trocar (surgical needle) that contains the fetal liver and thymus pieces (and sometimes also the genetically modified CD34+ cells) and inject them just under the kidney capsule but on top the kidney. (We chose the kidney because it has an excellent blood supply.) We close up the mouse and then IV inject more of the modified CD34+ cells. Some analgesics, etc, wait 8 weeks and begin assaying the mouse for human immune cells. These mice can be infected with HIV but remember it’s the human immune cells that are actually infected. We’ve never been able to detect HIV in any mouse cells. The human cells undergo the same depletion we see in humans until the mouse progresses to an AIDS-like disease. We don’t usually wait that long, as we want to assay the cells before the mouse gets too sick.

And there it is, your primer on humanized mice used for HIV gene therapy!

reply to post by AwakeinNM


It kills nothing. Hopefully, if the cells are normal, most just die out naturally and the remaining become memory T cells, which can "wake up" to fight again in the event you ever see HIV again.

reply to post by lonewolf19792000


Big pharma is VERY interested in this treatment for a number of reasons:

(1) It is currently quite a bit more expensive than HAART, even as measured over a lifetime.
(2) Likely requires more than one treatment
(3) "Biologics" offer essentially a lifetime patent because clinical trials on biologics (as opposed to chemical drugs) require the specific manufacturing plant making the biologic. So even when the patent technically runs out, if another company wants to make the biologic, they have to reapply for an IND (clinical trial) to show that their manufacturing process and biologic produced is safe and effective.

Again, big pharma is VERY interested in these kinds of treatments.

reply to post by fictitious


"Something useful with stem cells"? If you were really interested in when 'they were going to do something interesting with stem cells" you'd know about the dozens of clinical trials already underway for all sorts of neurological diseases, cancer, blood disorders, etc. Not to mention the hundreds of companies world-wide whose sole purpose is to develop stem cell-based treatments.

Laziness is no excuse for your ignorance. Check the literature before you make uninformed comments.

reply to post by Phagette


Wow, thank you for that informative and easy to understand explanation of such a complicated and controversial subject. It's exciting and amazing what you scientists can do these days. Way over my head!

Thank you so much for sharing this with ATS, and making this "dissertation" your first post. Welcome to ATS BTW. This info will stay in the ATS archives forever, and students of all kinds can Google key words and find your posts. I'm pretty sure information this simply put and concise isn't available anywhere else.

Thank you, Thank you, Thank you.

reply to post by ILikeStars


Its funny...this is wonderful, I have a family member with HIV, and I am almost positive as with any other terminal disease that is numbed with tons of perscription drugs, they will never be cured. For the mere fact that there isnt money in this, its like trying to sell the free energy that Tesla came up with, what happened to him?? Or the water powered engine...it competes with a multi-billion dollar per year industry. Thats why its April 15th and I havent heard a single person talk about this until I seen this post 2 minutes ago. Very nice though, better luck next time stem cells.

reply to post by trollertrollzo


There is potentially a lot of money in finding a cure for HIV. Just as there continues to be a lot of money made for companies that make/sell antibiotics which cure STIs (sexually transmitted infections) like Chlamydia, Syphilis, Gonorrhea. Just because we cure someone from their current infection, doesn't mean they didn't have a chance to infect someone else nor that they wont be re-infected in the future. Unlike bacteria, however, viruses are technically not living, and so finding ways to "kill" them are quite a bit trickier. For now, HAART treatment is quite effectively at keeping HIV viral loads low/undetectable. I just hope the side effects are manageable.

We are the Gods Now ... well of designer Cellular BIO Engineering...


More human than Human is Our Motto...

-- Dr. Eldon Tyrell


just imagine what a Synthetic Cell & Nano tech can DO... for Disease & Cure's


butt... Nature Has a Way


Slowly the Pandora's Box is Being Closed .... Hopefully ...



Researchers Say They Created a ‘Synthetic Cell’
By NICHOLAS WADE
Published: May 20, 2010

The genome pioneer J. Craig Venter has taken another step in his quest to create synthetic life, by synthesizing an entire bacterial genome and using it to take over a cell.

JUST WOW!!!!!!!!!

Synthetic cell may provide HIV vaccine / May 22, 2010
www.examiner.com...

New Synthetic Molecules Trigger Immune Response To HIV And Prostate Cancer

ScienceDaily (Nov. 5, 2009)
www.sciencedaily.com...

Researchers at Yale University have developed synthetic molecules capable of enhancing the body's immune response to HIV and HIV-infected cells, as well as to prostate cancer cells. Their findings, published online in the Journal of the American Chemical Society, could lead to novel therapeutic approaches for these diseases.

Just WOW Again !!!!!!!!!!


Vaccines Go Nanotech, Could Help Battle HIV
BY Kit Eaton | 02-22-2011 | 9:49 AM
www.fastcompany.com...

MIT scientists have worked out how to encase potent vaccines in nanoparticle shells--creating nanovaccine delivery systems, a trick that could have serious implications in fighting difficult-to-kill viruses like HIV.

reply to post by Phagette


Thank you very much for sharing what you know with us and bringing your explanations and professional opinions to this thread.

Much appreciated.

reply to post by Phagette


Thanks for expanding on what I begun, your posts are informative and digestive, Ill enjoy getting stuck in

reply to post by Rockpuck


I'm with you. In fact, an important goal for humanity is not only to understand our nature, but to prolong our nature in order to do so. Nature is so far from perfect, I think it's absolutely ridiculous we put it on a pedestal of sacredness. Nature is chaos. To order chaos to protect chaos from order, makes no sense. So live long.

not to piss on the parade here.

but posted already with the exact same title

got 2 replies...

LOL

good find nonetheless

reply to post by Phagette



just a little off topic but.....
every one of your posts were simply mind blowing!
You should take requests and start weekly threads on subjects like these and share your knowledge and experiences, I know there are a great amount of people on this forum who would enjoy it as much as I did!
Thank you!

Originally posted by Cataka
Sounds like a bunch of witchcraft and sorcery to me!

They should all be shut down and burned at the stake, because my religious morals are more important than saving lives! If you disagree with this, not only are you clearly wrong, but you're an anti-american terrorist!

I really do hope you were being ironic or sarcastic here. If not then I have this to say "why should your religious beliefs be able to impact on the discovery of cures for conditions because it upsets your sensibilities". Surely that is a form of terrorism.

Thats the reason why I think that George W Bush should be tried for crimes against Humanity in the banning of stem cell research. The man has held back the advancement of medical research and should be made to stand to account. And while wereat it lets have the Pope on the stand as well to defend why he is still against the use of Condoms.

reply to post by ILikeStars


Is it just me, or does this sound a bit like a prequel to "I am Legend"? I would say if this treatment actually does turn out to be affective, it will never hit the mainstream until stem cell research is legalized across the board, which I don't feel it will be, as that takes profits away from the Big Pharma corporations who treat all stem-cell curable disorders and diseases as just another way to make a buck. In order to cure things like AIDS and Hodgkins, etc, we would first have to lighten the wallets of Big Pharma, which is something that never goes over well. Hope is always good though, I suppose.

I'd like to tell the bibblists that the ones that die because they are denied stemcell benefits
might just be the raptured..
certainly they will be in heaven before ye...
waiting for their turn
to tell you no

Bah i think i'll stick with the South African cure of having sex with a virgin.