Th1/2 & Ig in humans

mdoherty mdoherty at atlas.niaid.nih.gov
Mon Jan 12 09:19:06 EST 1998


In article <34B9EDA0.192D at mpiib-berlin.mpg.de>, Jacob at mpiib-berlin.mpg.de wrote:

> Does anybody know whether or not in humans a similar phenomenon as in
> the mouse regarding Th1/Th2 reponses and Ig subtype release exists (Th1
> =IgG2a, Th2 = IgG1)? Are there subclasses different from IgE which
> correlate with Th1/Th2 responses in humans?

The short answer is yes - that Th1 and Th2 cells are easily identifiable in
humans and that polarised responses have been identified in a number of
diseases - including polarisation of Ig production. In addition to IgE,
IgG3 is also generally identified with Th2 responses and for the same
reason.

The longer answer is that the development of Th1/Th2 cells in response to
innfection has been simplified to the point where it is almost a parody. 
In the majority of infections, although Th1-like and Th2-like cells are
certainly induced and the balance of these contributes to (or in some cases
even determines) the outcome of the response, you generally do not end up
with an antigen-specific population which is totally biased one way or the
other.  In other words, Th1/2/3 cells can all be part of any defined
response, and the relative levels of other cytokines (often derived from
non-T populations, such as IL-10, TGF-B and IL-12) may be just as
important.  In addition, in some circumstances Tc1/2 cells and non-T, non-B
appear to be crucial factors in the resolution of infections.  So, while
important for control of many or perhaps most infections, in plenty of
other responses, Th1/2 switching does not seem to play a crucial role
(non-tuberculous mycobacteria is a common and prominent example of this).

Cheers, Mark



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