Recruitment of adult thymic progenitors is regulated by P-selectin and its ligand PSGL-1

Nat Immunol. 2005 Jun;6(6):626-34. doi: 10.1038/ni1203. Epub 2005 May 8.

Abstract

The molecular mechanisms that direct the migration of early T lymphocyte progenitors to the thymus are unknown. We show here that P-selectin is expressed by thymic endothelium and that lymphoid progenitors in bone marrow and thymus bind P-selectin. Parabiosis, competitive thymus reconstitution and short-term homing assays indicated that P-selectin and its ligand PSGL-1 are functionally important components of the thymic homing process. Accordingly, thymi of mice lacking PSGL-1 contained fewer early thymic progenitors and had increased empty niches for prothymocytes compared with wild-type mice. Furthermore, the number of resident thymic progenitors controls thymic expression of P-selectin, suggesting that regulation of P-selectin expression by a thymic 'niche occupancy sensor' may be used to direct progenitor access.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Movement
  • Endothelium / immunology
  • Endothelium / metabolism
  • Hematopoietic Stem Cells / cytology*
  • Hematopoietic Stem Cells / immunology
  • Hematopoietic Stem Cells / metabolism*
  • In Vitro Techniques
  • Ligands
  • Membrane Glycoproteins / deficiency
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • P-Selectin / genetics
  • P-Selectin / metabolism*
  • T-Lymphocytes / cytology*
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism*
  • Thymus Gland / cytology
  • Thymus Gland / immunology
  • Thymus Gland / metabolism

Substances

  • Ligands
  • Membrane Glycoproteins
  • P-Selectin
  • P-selectin ligand protein