question on Sequential transcriptional changes dictate safe and effective antigen-specific immunotherapy

Happyrn

33 Posts
Reply Posted on: Sep 7, 2014 at 2:44am
Hello,
Please tell me what you think about t following. Thank you.

Sequential transcriptional changes dictate safe and effective antigen-specific immunotherapy
http://www.nature.com/ncomms/2014/140903/ncomms5741/full/ncomms5741.html


Scientists discover how to ‘switch off’ autoimmune diseases
http://www.bris.ac.uk/news/2014/september/autoimmune-disease.html

Dr. Braverman

2026 Posts
RE: question on Sequential transcriptional changes dictate safe and effective antigen-specific immunotherapy Posted on: Sep 7, 2014 at 8:06pm
The authors studied the fate of CD4+ T cells using transgenic mice expressing a TCR specific for a peptide (named MBP) inducing an inflammatory response in encephalomyelitis (EAE).1/ This is a follow up study from the same team (15 years ago!!) showing the effects of that same peptide injected intra nasal, very high dose 100 ug.2/ They are able to induce an antigen specific tolerance using a dose escalation strategy by sc injection (6 injections from 0.08 ug to 80 ug, one injection/day, the three last injections are at the dose of 80 ug).3/ they detailed the molecular changes induced by the peptide in switching CD4+ T cells secreting IFN-gamma, IL-2, IL-6 to Treg like cells secreting IL-10 therefore preventing EAE.Increase in transcription factor C-Maf, NFIL3 targeting IL-10 promoter and inducing IL-10 transcription.This switch is mediated progressively as the injections are done.4/ There is an early peak in inflammatory cytokine levels that don’t compromise induction of the anti-inflammatory cytokines in their mice

Here are my thoughts about this:
20% of the individuals are not responsive to MBP.- Although cells phenotype switch from CD4+ to Treg cells, only 33% secrete IL-10.- Promising but not very efficient, the inflammatory peak preceding the switch to IL-10 production is of concern to me.- High risk of having an acute systemic inflammatory responsive if the dose is high (80 ug in sc while intra nasal it was fine ) (they showed that it happen when the dose of MBP is not given progressively).- No screening of others immune cells alteration to determine off target effects (!!!), IL-10 is produced massively by monocytes so they should have look at them as well.- A clinical study on anti-CD28 antibody (CD28 are required for T cell activation as well) in healthy patients led to multi-organ failure so there were off target effects

The paper essentially uses peptides corresponding to autoantigen epitopes that are recognized and “targeted” in a mouse model of experimental autoimmune encephalomyelitis (EAE – a very popular mouse inducible autoimmune model) to induce tolerance for the autoantigen through subcutaneous administration. They say that mucosal routes of administration (ie, intranasal) that are effective in animal models of autoantigen tolerance induction have not “translated well to the clinic” although they provide no references to support this (clearly their business strategy involves alternatives to . They show (in their mouse model) that subcutaneous injection of the autoantigen peptides at levels previously shown to be “safe and effective” in intranasal tolerance induction cause the production of high levels of pro-inflammatory cytokines in the serum of the mice. So they move to escalating dose immunotherapy (EDI) and show that by starting at low doses and sequentially moving to higher and higher doses they can reach levels that they find to be tolerogenic while avoiding the adverse effects of immediately starting with these high doses (actually not completely avoiding but delaying and abrogating the extent of their appearance in the serum). They show that the EDI approach induces higher rates of IL-10 producing CD4+ T cells compared with when a non-dose escalating approach is used, but they find an equal ability of these mice to avoid induction of EAE. They don’t seem to think that these IL-10 producing CD4+ T cells are traditional FoxP3 positive Treg cells but rather FoxP3 negative IL-10 producing CD4+ T cells. They reference some earlier papers but don’t actually look at that here. They do some fancy (exactly not so much fancy as expensive) transcriptome studies to look at sequential changes in gene expression in CD4+ T cells during their EDI approach and find upregulation of certain factors and downregulation of others. They are maybe interesting as biomarkers, but not really informative at all biologically since they only look at total CD4+ T cells instead of breaking the out into Treg and Teff populations. So, for example the upregulation of expression of PD-1 that they find is not found to be a good marker for their IL-10 producing T cells.Of course we’re not trying to treat autoimmune disease directly in Reproductive Immunology , but rather help the patient develop tolerance for paternal antigens. So the questions is how is this directly relevant to us, and LIT of course comes to mind. In this respect it is interesting that they were able to show induction of tolerance through a subcutaneous route of administration but there are several caveats in my mind. The first is that they are using autoantigens of course for looking at effects on autoimmune disease, and it’s not clear if these mechanisms would hold for non-self antigens. It’s not a trivial distinction as entirely separate populations of Treg cells are involved in response to self and non-self antigens and they develop differently. My main concern though is that when they use the same dose for subQ that is tolerogenic in a mucosal model, they find this massive induction of pro-inflammatory cytokines. They can delay and abrogate this to some extent by their EDI approach but I think this is telling that it doesn’t happen with mucosal administration. This fits with everything else that shows that mucosal tissue has a special role in tolerance induction (which of course makes sense with our ability to harbor beneficial commensal bacteria in our guts) and our thoughts that while introduction of paternal antigens through mucosal routes generally produce a tolerogenic response, their administration through other routes such as subQ do not (of course in the majority of our patients even muscosal induction of tolerance to paternal antigens is defective.They discuss the induction of the pro-inflammatory cytokines in terms of “safety” and whether it would cause immediate tissue damage to the host through toxic shock, etc. They don’t sufficiently explore though what this means for the nature of the T cell response to the antigen. Of course the production of pro-inflammatory cytokines suggests a non-tolerogenic response to the antigen – activation of antigen-specific Teff cells and subsequent formation of antigen-specific memory Teff cells. While their EDI approach seems to delay and decrease this it does not eliminate it. I don’t understand at all how this is an advantage over a mucosal approach where these cytokines aren’t induced at all by administration of these higher doses.The bottom line is that lower doses of antigen administration has repeatedly been shown to be more tolerogenic than high doses. This paper is a nice demonstration that the rheostat for this is set differently in mucosal tissue vs skin in that even the higher doses are immediately tolerogenic in mucosal tissues, while a dose escalating approach needs to be adopted to allow for a tolerogenic effect to these doses of antigen through the skin (and even then it does not seem to be as tolerogenic).
Dr. Jeffrey Braverman MD FACOG
Medical Director
Braverman Reproductive Immunology P.C.

Happyrn

33 Posts
Reply RE: question on Sequential transcriptional changes dictate safe and effective antigen-specific immunotherapy Posted on: Sep 8, 2014 at 1:02pm
THank you for your review! You make a number of valuable points in your review.

You are correct in that I was thinking of it being similar to LIT. I also agree with you that they do not delve into the target effects as much as they should have, nor the different responses of the various immune cells which is a concern particularly when you are dealing with the immune system and the potentially fatal effects that can occur.

Also, I am curious since they were doing studies on mice and they question the production of pro-inflammatory cytokines on tissue damage to the host, why could they not investigate further via autopsies on these mice to see what the effects were?

And are they really inducing tolerance through the subQ route if they are getting the production of pro-inflammatory cytokines? Also, just curious, is it possible to admin LIT via the mucosal approach since it is more tolerogenic? (I hope this makes sense and is not too stupid.)

Just a few questions and thank you again for your review

Dr. Braverman

2026 Posts
RE: question on Sequential transcriptional changes dictate safe and effective antigen-specific immunotherapy Posted on: Sep 8, 2014 at 1:42pm
mucosal LIT is called sex a> HLA on the sperm come in conatct with the vaginal mucosa. IF this is not working there is a problem with the induction of toleracne in the first place(again this is not autoimmune disease).
Dr. Jeffrey Braverman MD FACOG
Medical Director
Braverman Reproductive Immunology P.C.