11 min
Multiple Sclerosis Discovery -- Episode 95 with Dr. Michael Levy Multiple Sclerosis Discovery: The Podcast of the MS Discovery Forum
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- Medicine
[intro music]
Host – Dan Keller
Hello, and welcome to Episode Ninety-five of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m Dan Keller.
Today's interview features Dr. Michael Levy, associate professor of neurology at Johns Hopkins University. When we met in his office, he told me about his work on the role of T cells in neuromyelitis optica, or NMO. Finding antibodies to aquaporin-4 is indicative of NMO. But when Dr. Levy used aquaporin-4 reactive T cells, they could induce NMO in a mouse model, giving a clue to the role of T cells in the disease, and possibly opening up a new therapeutic avenue.
Interviewer – Dan Keller
What's different about this approach than what has been thought of previously?
Interviewee – Michael Levy
In neuromyelitis optica, there is the thought that the disease involves an antibody, the anti-aquaporin-4 antibody, that that antibody is involved in causing the disease. And what we demonstrated in this model is that we could recreate the disease simply by developing T cells against aquaporin-4. It's the exact same target as the antibody, but instead of using the antibody to exacerbate disease, we use T cells. And it works really well and causes optic neuritis and transverse myelitis, just like in the patient.
MSDF
Can you briefly describe your method?
Dr. Levy
We raised T cells in mice that don't have aquaporin-4. These mice see aquaporin-4 as a foreign antigen and mount an aggressive immune response against them, and we harvest those T cells from that animal. And what we do is we polarize them. We basically turn them into more aggressive types of immune cells in a dish. And then we transfer those T cells to a naïve mouse that does contain aquaporin-4. And those T cells attack the aquaporin-4, and it does so only in the optic nerves and the spinal cord and also a little bit in the brain.
MSDF
But aquaporin-4 is distributed more widely than that in the body.
Dr. Levy
That's correct. Actually, there's a higher level of aquaporin-4 in the lung, stomach, kidneys, muscle. Many tissues contain aquaporin-4, but the T cells decide which aquaporin-4 to attack. They are a thoughtful type of cell, and for whatever reason, and this is true in the human, too, the T cells only decide to go for those specific tissues.
MSDF
How does a mouse with aquaporin-4 get to an age where you can actually get these T cells out of it? What's the use of aquaporin-4 if they really can survive without it?
Dr. Levy
It's amazing that these knockout mice, they don't have any aquaporin-4, are completely viable. There are some abnormalities in function under certain stressful conditions, like stroke or brain trauma, but for the most part, they live normal lives. They must have a good compensatory mechanism that they don't need aquaporin-4, and that's fortunate for us because we can create these animal models.
MSDF
When you transferred these T cells to wild-type mice, what did you see?
Dr. Levy
Eight days after the transfer, the first thing we noticed is that the mice started blinking and the eyes became sunken into the head, and that's a sign of severe optic neuritis. And then two days later, they had a dragging tail. And a day after that, their hind limbs were paralyzed, and that indicated transverse myelitis.
MSDF
What's the role of the antibody if you can induce the disease with the T cell? And does the antibody in itself without T cells have an effect?
Dr. Levy
We looked at that, and what we found is that the antibody by itself has absolutely no effect. But in the context of a T cell attack, it can exacerbate the disease, and it does lend specificity to the pathology when you look at it under a microscope. If you add the antibody, there is more aquaporin-4 damage, and it recruits compliment, which causes that damage. So that's really the role of the antibody.
MSDF
Can you induce the antibody without T cells? Ess
[intro music]
Host – Dan Keller
Hello, and welcome to Episode Ninety-five of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m Dan Keller.
Today's interview features Dr. Michael Levy, associate professor of neurology at Johns Hopkins University. When we met in his office, he told me about his work on the role of T cells in neuromyelitis optica, or NMO. Finding antibodies to aquaporin-4 is indicative of NMO. But when Dr. Levy used aquaporin-4 reactive T cells, they could induce NMO in a mouse model, giving a clue to the role of T cells in the disease, and possibly opening up a new therapeutic avenue.
Interviewer – Dan Keller
What's different about this approach than what has been thought of previously?
Interviewee – Michael Levy
In neuromyelitis optica, there is the thought that the disease involves an antibody, the anti-aquaporin-4 antibody, that that antibody is involved in causing the disease. And what we demonstrated in this model is that we could recreate the disease simply by developing T cells against aquaporin-4. It's the exact same target as the antibody, but instead of using the antibody to exacerbate disease, we use T cells. And it works really well and causes optic neuritis and transverse myelitis, just like in the patient.
MSDF
Can you briefly describe your method?
Dr. Levy
We raised T cells in mice that don't have aquaporin-4. These mice see aquaporin-4 as a foreign antigen and mount an aggressive immune response against them, and we harvest those T cells from that animal. And what we do is we polarize them. We basically turn them into more aggressive types of immune cells in a dish. And then we transfer those T cells to a naïve mouse that does contain aquaporin-4. And those T cells attack the aquaporin-4, and it does so only in the optic nerves and the spinal cord and also a little bit in the brain.
MSDF
But aquaporin-4 is distributed more widely than that in the body.
Dr. Levy
That's correct. Actually, there's a higher level of aquaporin-4 in the lung, stomach, kidneys, muscle. Many tissues contain aquaporin-4, but the T cells decide which aquaporin-4 to attack. They are a thoughtful type of cell, and for whatever reason, and this is true in the human, too, the T cells only decide to go for those specific tissues.
MSDF
How does a mouse with aquaporin-4 get to an age where you can actually get these T cells out of it? What's the use of aquaporin-4 if they really can survive without it?
Dr. Levy
It's amazing that these knockout mice, they don't have any aquaporin-4, are completely viable. There are some abnormalities in function under certain stressful conditions, like stroke or brain trauma, but for the most part, they live normal lives. They must have a good compensatory mechanism that they don't need aquaporin-4, and that's fortunate for us because we can create these animal models.
MSDF
When you transferred these T cells to wild-type mice, what did you see?
Dr. Levy
Eight days after the transfer, the first thing we noticed is that the mice started blinking and the eyes became sunken into the head, and that's a sign of severe optic neuritis. And then two days later, they had a dragging tail. And a day after that, their hind limbs were paralyzed, and that indicated transverse myelitis.
MSDF
What's the role of the antibody if you can induce the disease with the T cell? And does the antibody in itself without T cells have an effect?
Dr. Levy
We looked at that, and what we found is that the antibody by itself has absolutely no effect. But in the context of a T cell attack, it can exacerbate the disease, and it does lend specificity to the pathology when you look at it under a microscope. If you add the antibody, there is more aquaporin-4 damage, and it recruits compliment, which causes that damage. So that's really the role of the antibody.
MSDF
Can you induce the antibody without T cells? Ess
11 min