Hello, I am wondering what peoples opinions are on the idea that TH1 and TH2
phenotypes that are localized in an infection are a result of differentiation
of the TH0 phenotype. Also, what are your feelings on a good definition of
TH1 and TH2 phenotypes. While the original definition was characterized
by multiple cytokines, it seems that more and more papers are focusing
just on Il4 and Il-10 to demonstrate a TH2 phenotype and Il-2 and IFN-gamma
to demonstrate a Th1 phenotype. Also, some labs use an Il-4/IFN-gamma
ratio rather than absolute numbers as a measure of the phenotype since
most cells secrete at least a little of both.
There is a lot of evidence to support the TH0---> Th1/Th2 concept
(but I dont have citations with me) and it seems to make sense in the same
way that monocytes are present in the blood stream and localize to tissue
and differentiate into macrophages.
I hope that this can spark some kind of discussion to liven up the group.