Synoviocyte-mediated expansion of inflammatory T cells in rheumatoid synovitis is dependent on CD47-thrombospondin 1 interaction

Abbe N. Vallejo, Hongyu Yang, Piotr A. Klimiuk, Cornelia M. Weyand, Jörg J. Goronzy

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


Fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis elicit spontaneous proliferation of autologous T cells in an HLA-DR and CD47 costimulation-dependent manner. T cell costimulation through CD47 is attributed to specific interaction with thrombospondin-1 (TSP1), a CD47 ligand displayed on FLS. CD47 binding by FLS has broad biological impact that includes adhesion and the triggering of specific costimulatory signals. TSP1+ FLS are highly adhesive to T cells and support their aggregation and growth in situ. Long-term cultures of T cells and FLS form heterotypic foci that are amenable to propagation without exogenous growth factors. T cell adhesion and aggregate formation on TSP1+ FLS substrates are inhibited by CD47-binding peptides. In contrast, FLS from arthroscopy controls lack adhesive or T cell growth-promoting activities. CD47 stimulation transduces a costimulatory signal different from that of CD28, producing a gene expression profile that included induction of ferritin L chain, a component of the inflammatory response. Ferritin L chain augments CD3-induced proliferation of T cells. Collectively, these results demonstrate the active role of FLS in the recruitment, activation, and expansion of T cells in a CD47-dependent manner. Because TSP1 is abundantly expressed in the rheumatoid synovium, CD47-TSP1 interaction is proposed to be a key component of an FLS/T cell regulatory circuit that perpetuates the inflammatory process in the rheumatoid joint.

Original languageEnglish (US)
Pages (from-to)1732-1740
Number of pages9
JournalJournal of Immunology
Issue number4
StatePublished - Aug 15 2003

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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