Recycled IL-7 Can Be Delivered to Neighboring T Cells

  • J Immunol. 2015 May 15;194(10):4698-704. doi: 10.4049/jimmunol.1400560.
Douglas A Bazdar  1 ,  Magdalena Kalinowska  2 ,  Soumya Panigrahi  1 ,  Scott F Sieg  3
Affiliations
  • 1. Division of Infectious Diseases and HIV Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106; and.
  • 2. Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461.
  • 3. Division of Infectious Diseases and HIV Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106; and [email protected].
PMID: 25870237 DOI: 10.4049/jimmunol.1400560
Abstract

IL-7 is a key homeostatic cytokine that provides signals for T cell survival and proliferation in vivo. In this article, we provide evidence that IL-7 utilization is enhanced by a novel mechanism of cytokine "recycling" during which T cells treated with rIL-7 are rapidly induced to express p-STAT5 and are subsequently able to recycle biologically active cytokine for release to neighboring cells in soluble form. Our observations indicate that the ability of cells to recycle IL-7 is dependent on IL-7R α-chain (CD127) and endocytosis, consistent with a model whereby IL-7 is internalized via receptor interactions before recycling. These observations provide evidence of a novel mechanism that enables cells to optimally use IL-7.