From: Kofi on
<http://www.sciencedaily.com/releases/2010/01/100120144003.htm>

Switch Turns on Allergic Disease in People

ScienceDaily (Jan. 22, 2010) � A new study in human cells has singled
out a molecule that specifically directs immune cells to develop the
capability to produce an allergic response. The signaling molecule,
called thymic stromal lymphopoietin (TSLP), is key to the development of
allergic diseases such as asthma, atopic dermatitis (eczema), and food
allergy.

The study team, led by Yong-Jun Liu, M.D., Ph.D., at the University of
Texas M.D. Anderson Cancer Center, Houston, focused on dendritic cells,
immune cells that initiate the primary immune response. Dendritic cells
come into contact with other immune cells known as T cells, causing them
to develop into different subsets of T cells, including helper 1 (Th1)
and helper 2 (Th2) cells. These T-cell subsets are involved in
protective immune responses, but the Th2 cells can also drive an
allergic response. Until now, it was not known how dendritic cells
induced T cells to become Th2 cells.

The investigators used dendritic cells isolated from the blood of
healthy donors and found that the binding of TSLP to these cells
activates a distinct set of signaling pathways within the cells. As a
result, the dendritic cells produce messenger molecules that act on the
T cells, causing them to develop into Th2 cells.

The study identifies TSLP as a switch that causes the development of the
allergic response in people and suggests that this molecule may be a
potential therapeutic target to treat and prevent allergic diseases.

Dr. Liu and his colleagues are supported by the National Institute of
Allergy and Infectious Diseases (NIAID), part of the National Institutes
of Health. The investigators are with the Asthma and Allergic Diseases
Cooperative Research Centers program, now in its fourth decade of
continuous funding as the cornerstone of NIAID's asthma and allergy
research portfolio.
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Story Source:

Adapted from materials provided by NIH/National Institute of Allergy and
Infectious Diseases.
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Journal Reference:

1. K Arima et al. Distinct signal codes generate dendritic cell
functional plasticity. Science Signaling, 2010; DOI:
10.1126/scisignal.2000567
From: Trawley Trash on
On Wed, 27 Jan 2010 05:09:20 -0600
Kofi <kofi(a)anon.un> wrote:

> These T-cell subsets are involved in protective immune
> responses, but the Th2 cells can also drive an allergic
> response.

AFAIK there is no difference between a normal immune response
and an allergic response. When the response is provoked
by an invading organism, we call it immunity. When the
response is provoked by something we eat, we call it an
allergy or a toxic response depending on whether the
substance is supposed to be food or poison.