Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

Interleukin-7 (IL-7) plays a central role in the homeostasis of the T-cell compartment by regulating T-cell survival and proliferation. Whether IL-7 can influence T-cell receptor (TCR) signaling in T cells remains controversial. Here, using IL-7-deficient hosts and TCR-transgenic T cells that conditionally express IL-7R, we examined antigen-specific T-cell responses in vitro and in vivo to viral infection and lymphopenia to determine whether IL-7 signaling influences TCR-triggered cell division events. In vitro, we could find no evidence that IL-7 signaling could costimulate T-cell activation over a broad range of conditions, suggesting that IL-7 does not directly tune TCR signaling. In vivo, however, we found an acute requirement for IL-7 signaling for efficiently triggering T-cell responses to influenza A virus challenge. Furthermore, we found that IL-7 was required for the enhanced homeostatic TCR signaling that drives lymphopenia-induced proliferation by a mechanism involving efficient contacts of T cells with dendritic cells. Consistent with this, saturating antigen-presenting capacity in vivo overcame the triggering defect in response to cognate peptide. Thus, we demonstrate a novel role for IL-7 in regulating T cell-dendritic cell interactions that is essential for both T-cell homeostasis and activation in vivo.

Original publication

DOI

10.1182/blood-2008-12-192252

Type

Journal article

Journal

Blood

Publication Date

06/2009

Volume

113

Pages

5793 - 5800

Addresses

Medical Research Council Centre for Immune Regulation, Division of Immunity and Infection, Birmingham University, Birmingham, United Kingdom.

Keywords

Dendritic Cells, T-Lymphocytes, Animals, Mice, Knockout, Mice, Receptors, Antigen, T-Cell, Receptors, Interleukin-7, Interleukin-7, Antigens, Lymphocyte Activation, Signal Transduction, Substrate Specificity, Homeostasis