Partial activation precedes apoptotic death in T cells harboring an IAN gene mutation.
Eur J Immunol
; 34(9): 2396-406, 2004 Sep.
Article
em En
| MEDLINE
| ID: mdl-15307172
ABSTRACT
The Biobreeding diabetes-prone rat suffers from a profound peripheral lymphopenia and yet succumbs to a T cell-dependent autoimmune disease. Lymphopenia segregates with a mutated chromosomal locus, termed lyp, recently identified as a frameshift mutation in IAN4. Others have correlated loss of IAN4 function with decreased mitochondrial integrity resulting in T cell apoptosis. Here we report that IAN4-/- T cells enter a state similar to that of partial activation wherein they down-regulate CD62L and undergo incomplete blasting yet do not progress through mitosis. When given a strong stimulus, this partial activation phenotype can be overcome. This phenotype can be recapitulated in wild-type T cells through suboptimal stimulation. The phenotype is not simply a reaction to the lymphopenic environment, as spontaneous CD62L down-regulation occurs in mature single-positive medullary thymocytes that develop within a non-lymphopenic environment, and normal T cells do not undergo similar blasting when parked in a lymphopenic environment. Finally, we show that IAN4-/- T cells are more readily triggered via TCR stimulation. Thus, in addition to their role in apoptosis, IAN family members may also play a role in regulating the T cell activation state through modulation of TCR signaling strength.
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Base de dados:
MEDLINE
Assunto principal:
Ativação Linfocitária
/
Linfócitos T
/
Antígenos de Histocompatibilidade Classe II
/
Apoptose
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article