A cell-cycle independent role for p21 in regulating synovial fibroblast migration in rheumatoid arthritis.

Rheumatoid arthritis (RA) is characterized by synovial hyperplasia and destruction of cartilage and bone. The fibroblast-like synoviocyte (FLS) population is central to the development of pannus by migrating into cartilage and bone. We demonstrated previously that expression of the cell cycle inhibitor p21 is significantly reduced in RA synovial lining, particularly in the FLS.

Cord blood CD4(+)CD25(+)-derived T regulatory cell lines express FoxP3 protein and manifest potent suppressor function.

CD4(+)CD25+ T regulatory (Treg) cells have been shown to critically regulate self and allograft tolerance in mice. Studies of human Treg cells have been hindered by low numbers present in peripheral blood and difficult purification. We found that cord blood was a superior source for Treg-cell isolation and cell line generation compared with adult blood.

In vitro-expanded human CD4(+)CD25(+) T-regulatory cells can markedly inhibit allogeneic dendritic cell-stimulated MLR cultures.

CD4(+)CD25(+) T-regulatory (Treg) cells have been shown to critically regulate self- and allograft tolerance in several model systems. Studies of human Treg cells have been restricted by the small number present in peripheral blood and their naturally hypoproliferative state. To better characterize Treg suppressor cell function, we determined methods for the isolation and expansion of these cells.