Programmed death-1 (PD-1) defines a transient and dysfunctional oligoclonal T cell population in acute homeostatic proliferation.
J Exp Med
; 204(10): 2321-33, 2007 Oct 01.
Article
em En
| MEDLINE
| ID: mdl-17785507
ABSTRACT
The host responds to lymphopenic environments by acute homeostatic proliferation, which is a cytokine- and endogenous peptide-driven expansion of lymphocytes that restores the numbers and diversity of T cells. It is unknown how these homeostatically proliferating (HP) cells are ultimately controlled. Using a system where lymphocytic choriomeningitis virus-immune C57BL/6 splenocytes were transferred into lymphopenic T cell-deficient hosts and allowed to reconstitute the environment, we defined the following three populations of T cells slowly dividing Ly6C+ cells, which contained bona fide virus-specific memory cells, and more rapidly dividing Ly6C- cells segregating into programmed death (PD)-1+ and PD-1- fractions. The PD-1+ HP cell population, which peaked in frequency at day 21, was dysfunctional in that it failed to produce interferon gamma or tumor necrosis factor alpha on T cell receptor (TCR) stimulation, had down-regulated expression of interleukin (IL)-7Ralpha, IL-15Rbeta, and Bcl-2, and reacted with Annexin V, which is indicative of a preapoptotic state. The PD-1+ HP cells, in contrast to other HP cell fractions, displayed highly skewed TCR repertoires, which is indicative of oligoclonal expansion; these skewed repertoires and the PD-1+ population disappeared by day 70 from the host, presumably because of apoptosis. These results suggest that PD-1 may play a negative regulatory role to control rapidly proliferating and potentially pathogenic autoreactive CD8+ T cells during homeostatic reconstitution of lymphopenic environments.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Linfócitos T
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Proteínas Reguladoras de Apoptose
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Homeostase
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Antígenos de Superfície
Limite:
Animals
Idioma:
En
Revista:
J Exp Med
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Estados Unidos