|
|
|
|
|
|
|
||
Chain Plays an Essential
Role in Regulating Lymphoid Homeostasis
By
From the * Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute,
Bethesda, Maryland 20892; and the In the immune system, there is a careful regulation not only of lymphoid development and
proliferation, but also of the fate of activated and proliferating cells. Although the manner in
which these diverse events are coordinated is incompletely understood, cytokines are known to
play major roles. Whereas IL-7 is essential for lymphoid development, IL-2 and IL-4 are vital
for lymphocyte proliferation. The receptors for each of these cytokines contain the common
cytokine receptor Division of Hematologic Products, Food and Drug
Administration, Bethesda, Maryland 20892
chain (c), and it was previously shown that c-deficient mice exhibit severely compromised development and responsiveness to IL-2, IL-4, and IL-7. Nevertheless,
these mice exhibit an age-dependent accumulation of splenic CD4+ T cells, the majority of
which have a phenotype typical of memory/activated cells. When c-deficient mice were
mated to DO11.10 T cell receptor (TCR) transgenic mice, only the T cells bearing endogenous TCRs had this phenotype, suggesting that its acquisition was TCR dependent. Not only
do the CD4+ T cells from c-deficient mice exhibit an activated phenotype and greatly enhanced incorporation of bromodeoxyuridine but, consistent with the lack of c-dependent survival signals, they also exhibit an augmented rate of apoptosis. However, because the CD4+
T cells accumulate, it is clear that the rate of proliferation exceeds the rate of cell death. Thus,
surprisingly, although c-independent signals are sufficient to mediate expansion of CD4+
T cells in these mice, c-dependent signals are required to regulate the fate of activated CD4+
T cells, underscoring the importance of c-dependent signals in controlling lymphoid homeostasis.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
| TABLE OF CONTENTS |
|
