may be a re-posting, though unable to find it :

Can we reprogram the immune system?
28 January 2009 by Linda Geddes


http://www.newscientist.com/article/...ne-system.html

summary of 2 separate studies concerning immune cells
which has direct implication for the use of vaccines (at least in vitro), and why they
may result in dire effects.

immune system more flexible than previously
thought? T-helper (Th) cells "thought to be of 2
types: Th1 which sent viruses and bacteria from host cells and Th2
cells that fought parasites and bacteria in blood in other body
fluids and also fought allergens." 2 new classes of cells were
discovered: "regulatory T cells (T-regs) which attenuate the immune
system response and Th17 cells that trigger inflammation and
autoimmunity. Problem with this categorization was discovered when
the T-regs behaved like Th1 cells when the T-regs cells were exposed
to the molecules that normally result in a Th response. "(Immunity,
COI:10:1016/j.immuni.2008.12.009)...

Whoops--

In addition, study by Casey Weaver at Univ of Alabama showed
that "Th17 cells can also morph into Th1-like cells" under certain
conditions. Article concludes that "if Th1 cells are equally flexible
vaccines may not work as they are intended, says Christopher Wilson
of the Univ of Washington State in Seattle. For instance, if a
vaccine against a virus triggers a Th1 response but the Th1 cells
change their identity for some reason, 'the pathogen might yet
subvert the protection induced by the vaccine,he says"...

Occurs to me, if this happens in other than a petri dish, vaccines may result in immune responses in which
the correct immune cell morphs into the wrong cell--causing
inflammation or autoimmunity when none was wanted.......author cites
the safety study in which 6 individuals in Northwick park hosp in
london in March, 06, were given a drug that was to activate T-reg
cells, but instead they were made seriously ill. author notes that "there may be serious implications for immunotherapy trials in which T-regs are injected into people with autoimmune disease to dampen their immune response"...Perhaps the T-regs
morphed into Th17 causing an autoimmune response????