Maset, here's the full portion of that section of the transcript:
It turns out that the undifferentiated embryonic stem cell and the differentiating cells that we make and put into animals are not recognized by the human immune system and we published this last year. It's a striking finding.
If I were to mix my blood with yours and yours with mine, my immune cells in that blood test would react against you because we're different HLA tissue types. As would you react to me and that's basically what happens if you were to take a kidney transplant from me or vice versa which is why organ transplants are traditionally associated with for life high dose immune suppression. These are allografts, in that the cells that we're gonna put into your spinal cord are made from what would have been an embryo with a different tissue type from yours so you're right to ask, well will I need immune suppression. So, to our surprise, when we mix undifferentiated embryonic stem cells with people's blood with a different tissue type, they don't react to them. Moreover, in that example of your blood mixed with my blood, if we drop undifferentiated embryonic stems cells into that test tube, those cells would stop your body from recognizing me and vice versa, me from recognizing you. Moreover, the differentiating cells including the OPCs that we're talking about here, are negative in those same aspects.
Now, what's that all about? Well, you've got to go back to the source of the biology and spend a little bit of time talking about the immunology of embryo implantation because that process is no different than an allograft transplantation into a woman's uterus because the embryo, with respect to the mother, is an allograft. It has mother and father tissue antigens so the question arises why doesn't the pregnant woman immunologically reject that implanted embryo and they never do that and the reason is the blastomeres in the blastocyst, those are the cells from which embryonic stem cells are derived have learned how to create an immune tolerant or an immune protective region in the uterus that prevents mothers' T cells from recognizing and killing that implanting allograft and, lo and behold, the embryonic stem cell has retained that capability so there's something in the membrane of both the undifferentiated stem cell and the differentiating cells we make from them that prevents the T cell which recognizes its alloness from reacting to it so the T cells don't activate so that suggests that for all of these therapies, whether it's OPCs into the spinal cord, cardiomyocites into the heart, islets into the liver, whatever, we will not need high dose for life immune suppression. Now with the particular case of the oligodendrocyte spinal cord injury opportunity, there's a further safety factor because once the injury heals, you are once back into the protected site of the central nervous system which is an immune privileged site further reducing the likelihood of immune detection of these OPCs. Nevertheless because we want to test one variable at a time, in the clinical protocol we will cover the patients with low dose cyclosporin for about three months and then withdraw it by which time the lesion should be healed and there should be no egress of any immune cell into that spinal cord lesion.
Now, that's sort of the near term biology? There is a second generation approach that we'll be announcing later this year which should completely eliminate the need for any immune suppression for any of these cells and that has to do with a way to immunologically tolerize you or me to any of the cells made from a particular stem cell line and here's how this works -- and this can only be done with embryonic stem cells because these are the only stem cells that are pluripotent, that you can make all cell types of the body from each of our lines so one of the cell types that we know how to make are immune cells and specifically these are dendritic cells and there's a certain kind of subset of a dendrit
The cells Dr. Lima transplants do come from an adult source, but characterizing them as stem cells is incorrect. I have written about this before.
I have also written about the umbilical cord blood stem cell transplants.
Interestingly, the surgery involved in both transplants involves decompression surgery. Decompression of a compressed cord, by itself, can lead to substantial gains.
Of more interest, the doctors in South Korea are developing a percutaneous method of delivering the UCBSCs that will not involve surgery. When performed (preferably in a controlled study), this will definitely prove or disprove if it works.
I was impressed with the deliberate contamination of the OPC1 cells with ESCs to see what would happen if a rogue ESC got loose, and some other comments that I failed to include in the Q&A. (The full transcript of the interview was right around 9600 words, so I had to condense a good bit.)
Still, I guess this is offtopic. It's an interesting article.
Thanks 1984.
BTW, my comment on trusting the safety of the trial has nothing to do with Okarma as a person (who I do not know well enough to judge), rather it was based on the fact that he expressed no reservations about addressing concerns that are raised about the safety before moving into human trials.
Slashdot Mirror
I'll second this. They've done the same for me before with my computer.
Anytime. I'm happy to help.
Maset, here's the full portion of that section of the transcript:
The cells Dr. Lima transplants do come from an adult source, but characterizing them as stem cells is incorrect. I have written about this before.
I have also written about the umbilical cord blood stem cell transplants.
Interestingly, the surgery involved in both transplants involves decompression surgery. Decompression of a compressed cord, by itself, can lead to substantial gains.
Of more interest, the doctors in South Korea are developing a percutaneous method of delivering the UCBSCs that will not involve surgery. When performed (preferably in a controlled study), this will definitely prove or disprove if it works.
Unfortunately, that's a big misconception. Dr. Carlos Lima transplants the nasal mucosa, not stem cells.
This treatment works the same way as Geron's. All-in-all, pretty cool.
Seth, they are embryonic, and that is discussed in the interview. The title can only be a certain length, so Embryonic was not included.
Would you mind relaying to me which stem cell trials are curing paralysis?
The writer is a narcissistic nitwit.
Yet you post as an Anonymous Coward.
I was impressed with the deliberate contamination of the OPC1 cells with ESCs to see what would happen if a rogue ESC got loose, and some other comments that I failed to include in the Q&A. (The full transcript of the interview was right around 9600 words, so I had to condense a good bit.)
Still, I guess this is offtopic. It's an interesting article.
Thanks 1984.
BTW, my comment on trusting the safety of the trial has nothing to do with Okarma as a person (who I do not know well enough to judge), rather it was based on the fact that he expressed no reservations about addressing concerns that are raised about the safety before moving into human trials.