Answer to a few questions about
MAIT cells and Old Mike's question if folate fortification could activate them directly.
Short answer - it's doubtful so this is a good thing. Seems they will follow the same rules as all other T-cell where co-stimulation is probably required.
Also we learn a little bit about
the research world, where one group claims to have figured it all out... when in fact this is not the case. Funny bunch these researchers are.
I apologize that I could not get back to you sooner. I was traveling and had limited access to the Internet.
Very interesting questions!
I guess you may be aware of a recent paper that shows MAIT cells are activated in IBDs.www.ncbi.nlm.nih.gov/pubmed/24450998
- However, how MAIT cells are activated and what roles they play (offender vs. defender) in IBDs need further investigation. It is also an ongoing debate if MAIT cells are activated by vitamin B metabolites alone (on antigen presenting cells) or by other non-cognate inflammatory signals. There is evidence that MAIT cells can be activated by non-cognate signals. Here is an example-- www.ncbi.nlm.nih.gov/pubmed/24019201
I myself have done research on MAIT cells and their cognate antigen MR1 (which binds vitamin B metabolites) in animal models and cell culture systems. A popular hypothesis in the field is that MAIT cells distinguish bacterial or fungal species according to microbial enzymatic pathways to make vitamin B metabolites. But, I can tell you from my own experiences, that is not the case. MAIT cells can be activated by bacteria that do NOT make vitamin B metabolites. My personal idea is that MAIT cells require both MR1-vit. B metabolites complex AND at least one inflammatory signal to be activated. This model if proven true would explain why MAIT cells do not randomly attack cells in the intestinal tract that harbors a ton of vitamin B metabolite-making commensal microbes. Does this make sense?
I myself suffer from a gastrointestinal motility disorder, so I understand this constant worry/concern about
food, drink, supplement...etc. pretty much everything that I put into my mouth. While it is "easy" to say," just stop taking vitamin B supplement to avoid the aggravation of symptoms", I feel we may be missing a good chance to help advance research. As I said, I do most of my research in mice and cells, but I can try to convey your observations and ideas on Crohn's disease, vitamin Bs and MAIT cells to colleagues who do clinical research.