This one may get me into trouble, but it makes me disillusioned about the value of some animal work. I realise that I am becoming the grumpy old git. However, we have made the point that (a) B cells may be important targets for therapy in MS and (b) that mouse EAE is T cell mediated and doesn’t particularly respond to CD20. This is in our research area. It is important that we address papers that challenges our view and in doing so help you to understand our position. Some of you will say I am not interested. Why is it interesting to me? Because you are supporting this work perhaps in the form of your taxes.
B cell aggregates are important ,events in MS and they can be seen in animals. However, are the routes to these events the same? There are a few labs that are doing this B cell work and we should understand divergent views occur. I am more and more convinced that it is a waste of time investigating CD20 therapy in mouse EAE.
In this study they make the post that the B cell aggregates are T cell dependent. I have no problem with this as the disease is T cell-mediated, with some B cell help. However the model has limited validity. They knock out CD49d which is the target for natalizumab and the knockout is like permenant natalizumab treatment but what happens? Disease is not inhibited as occurs in humans, but it is apparently made worse.
Our work shows EAE is CD4 dependent. We deplete either the CD4 T cells (red line) CD8 T cells (navy blue line) and CD20 B cells using depleting (d) monoclonal antibodies (mAb). We treat with CD4 and up to day 24 on 10% have got disease so 90% didnt get disease. If we treat with a dummy drug all animals have disease by day 18. All animals with their CD8 depleted have disease by day 16 and 90% of the animals have disease by day 18 if they are B cell depleted. Therefore there is minimal (read no) influence of B cell depletion.
There is no discussion of this important difference but it means that the rest of the paper is based on a biology that is clearly different between rodents and humans and therefore the significance is debateable. I do not think that CD49 is the major migration related molecule in mice and this is why there is a difference.
I have become increasing satisfied that our view is closer to the reality than is portrayed in the literature. We seem to have a culture where the abstract of the paper is the take home message and the data is not looked at. When it is presented at meetings. It is not challenged.
The only way for me to convince you, is to challenge the data when it shows a positive effect and do it in a constructive way. There is no point in saying it is Sh1. It does not do me any favours with my peers who will see me as an A-hole but this is where your hard earned tin-rattling is sometimes going. It important that you can read a paper.
However, there is obviously a writing style because it keeps surfacing in so-called good journals. I am convinved the writing style is a learned behaviour and includes the view that if the data doesn’t show what you want it to show, just say it did and you won’t be questioned by the referee. They may not look at the figures because there are too many to look at and these occur at the end of the paper. This is why you do everything, the in vitro studies the EAE experiment and the histology over and over again so you dont look for dogey data when you do Science Three Ways.
So first up we have treatment before disease occurs (See below). It is hardly disease inhibition. 67% verses 89% different, but is it biologically different. I doubt it. Does it pass the “smack you in the eye test”. Definately not. They say there is a delay, but there is a massive deviation 43-11= 32 and 34 + 5 = 39 so there is a big overlap. There is no statitistics and this does not convince me. If this was a human study 70% of people relapsing would not be considered to be a treatment. It this was in humans there would be no ocrelizumab. If anything the animals that gets disease could be worse, but the smack you in the eye test says there is no effect. Anti-CD20 does not work in this model. The data supports our conclusions.
Next up they treat at onset. Again anti-CD20 depletion does nn
B cells in the brain, good guys or bad guys? In this study they look at Me Bags?
What are they? Some type of trouser? No they are meningeal B cell aggregates (MEBAGs). So clusters of B cells on the surface of the brain. In MS they have been suggested to be a risk factor for worse disease. However, because they produce interleukin-10 that suppresses T cells, it is asked if they are good guys and should not be manipulated. This question is relevant to NDG, who is doing a study to try and remove antibody-producing cells from the brain.
Mitsdörffer M, Di Liberto G, Dötsch S, Sie C, Wagner I, Pfaller M, Kreutzfeldt M, Fräßle S, Aly L, Knier B, Busch DH, Merkler D, Korn T. Formation and immunomodulatory function of meningeal B-cell aggregates in progressive CNS autoimmunity. Brain. 2021 Mar 9:awab093. doi: 10.1093/brain/awab093.
Meningeal B lymphocyte aggregates have been described in autopsy material of patients with chronic multiple sclerosis. The presence of meningeal B cell aggregates has been correlated with worse disease. However, the functional role of these meningeal B cell aggregates is not understood.
Here, we use a mouse model of multiple sclerosis, the spontaneous opticospinal encephalomyelitis model, which is built on the double transgenic expression of myelin oligodendrocyte glycoprotein-specific T cell- and B cell-receptors, to show that the formation of meningeal B cell aggregates is dependent on the expression of α4 integrins by antigen-specific T cells.
OK, optico spinal encpehalomyelitis is really just called mouse EAE as most EAE models in rodents show spinal cord lesions and they can occur in the optic nerve but they show limited brain involvment. They were once called Devics mice and as Devics MS is no longer MS but neuromyelitis optica (NMO) where you can get myelin oligodendrocyte glycoprotein NMO,. Is this model of MS or NMO?. However, most mouse models irrespective of the antigen used to induce the disease have few lesions in the brain. Here they imply they are formed by the action of alpha 4 integrin which is the target for natalizumab. (Alarm bells ring for me. Why? Do your home work and evidence that this pathway is critical in mice is weak.). Next up
T cell-conditional genetic ablation of α4 integrins in opticospinal encephalomyelitis mice impaired the formation of meningeal B cell aggregates, and surprisingly, led to a higher disease incidence as compared to opticospinal encephalomyelitis mice with α4 integrin-sufficient T cells.
They remove alpha 4 from T cells, so the view would be that the dont migrate into the brain….however disease is worse…so they do, so it kind or argues against this being important in getting T cells in the brain (Not surprising if mouse T cells use other molecules to migrate into the inflammed brain). But at this point the study loses validity for human studies as the mouse is different. Next up
B cell-conditional ablation of α4 integrins in opticospinal encephalomyelitis mice resulted in the entire abrogation of the formation of meningeal B cell aggregates, and opticospinal encephalomyelitis mice with α4 integrin-deficient B cells suffered from a higher disease burden than regular opticospinal encephalomyelitis mice.
They remove alpha 4 integrin from B cells and they get no aggregates forming but again disease was worse. So even less validity. However this is unlike regular EAE were B cell deficiency of alpha 4 integrin has no effect on disease. I am not going to critque this as cannot see the figures.
While anti-CD20 antibody-mediated systemic depletion of B cells in opticospinal encephalomyelitis mice after onset of disease failed to efficiently decrease meningeal B cell aggregates without significantly modulating disease progression, treatment with anti-CD19 chimeric antigen receptor-T cells eliminated meningeal B cell aggregates and exacerbated clinical disease in opticospinal encephalomyelitis mice.
OK wait until disease occurs and anti-CD20 doesn’t work. This is not surprising as it does very little in regular EAE. This is because it is a T cell-mediated condition.
Since about 20 percent of B cells in organised meningeal B cell aggregates produced either IL-10 or IL-35, we propose that meningeal B cell aggregates might also have an immunoregulatory function as to the immunopathology in adjacent spinal cord white matter.
So again we have regulatory B cells in the CNS aggregates . So beware NDG.
The immunoregulatory function of meningeal B cell aggregates needs to be considered when designing highly efficient therapies directed against meningeal B cell aggregates for clinical application in Multiple Sclerosis.
So do we say Schtop? The question is what is the human study showing? If we get rid of oligoclonal bands, is it going to be disaster zone?
This post was not supposed to launch today but whilst doing this another paper surfaced and again it s a story we have been following for years and that is salt. The original work in Nature. As MD2 pointed out the dose was equivalent of half a kilogramme of salt a day, which in humans would make you vomit and may well killl you but mice cant vomit. It made EAE worse , and so the inference was beware of McDonuts. As too much salt is bad for you. I guess one of those NSS moments. However the plot thickens and I start off with the end of the paper
“Our results call for special care in selecting or combining representative experimental models for translation into clinical medicine”.
A pinch of salt is now good for you…if you are a mouse….Should we take it with a pinch of salt?
So I now ask you to think because these posts use the same model as the one above. Is this model translationally suited the influence of CD49d inhibition and CD20 are both different to humans….So is it suited?
What about salt intake.
In this study the mice didnt do what it was supposed to do.
In the past a high salt diet was reported to make EAE worse. Now we have it making it better because it stresses the animals out and they dont get blood brain barrier breakdown.
One mouse does this another mouse does that suggesting that the clinical trial will show nothing…..yet we can see what it does in humans as a trial is being done. results soon, but the end point are Th17. In this study they are made but dont get in the brain, so predicts the MS trial will be a mess we will have to see. Which ever way it happens the mouse work is going to be right.
High-salt diet suppresses autoimmune demyelination by regulating the blood-brain barrier permeability.Na SY, Janakiraman M, Leliavski A, Krishnamoorthy G.Proc Natl Acad Sci U S A. 2021 Mar 23;118(12):e2025944118. doi: 10.1073/pnas.2025944118
Dietary salt intake has been considered an important risk factor for autoimmune diseases like multiple sclerosis (MS). Here we studied the effects of a high-salt diet (HSD) using a spontaneous autoimmune disease mouse model resembling MS. We found that high-salt consumption protects mice from developing the neurological disease by promoting the tightening of the blood–brain barrier and preventing the migration of autoreactive T cells into the CNS. Our results emphasize the multifarious effects of high-salt consumption in autoimmune disease susceptibility.Sodium chloride, “salt,” is an essential component of daily food and vitally contributes to the body’s homeostasis. However, excessive salt intake has often been held responsible for numerous health risks associated with the cardiovascular system and kidney. Recent reports linked a high-salt diet (HSD) to the exacerbation of artificially induced central nervous system (CNS) autoimmune pathology through changes in microbiota and enhanced TH17 cell differentiation [M. Kleinewietfeld et al., Nature 496, 518-522 (2013); C. Wu et al., Nature 496, 513-517 (2013); N. Wilck et al., Nature 551, 585-589 (2017)]. However, there is no evidence that dietary salt promotes or worsens a spontaneous autoimmune disease. Here we show that HSD suppresses autoimmune disease development in a mouse model of spontaneous CNS autoimmunity. We found that HSD consumption increased the circulating serum levels of the glucocorticoid hormone corticosterone. Corticosterone enhanced the expression of tight junction molecules on the brain endothelial cells and promoted the tightening of the blood-brain barrier (BBB) thereby controlling the entry of inflammatory T cells into the CNS. Our results demonstrate the multifaceted and potentially beneficial effects of moderately increased salt consumption in CNS autoimmunity.
A great many studies will have the same mechanism you stress mice out and they dont get EAE, just up and up the dose so that it does something…Stopping EAE makes papers. We call it the “building site effect” put mice next to a building site the vibrations subsonic mice stresses the animals out. So what is right?…use a sensible dose and it does very little I suspect. Problem is you dont know what to believe. I am sure that ProfG in his MS preventative hat would say use Salt in moderation, just as do most things in moderation.