MHC class II-expressing renal tubular epithelial cells (TEC) are able to present foreign
peptide antigens to T cells. The costimulatory signals that are required for effective T cell
activation upon antigen presentation by TEC have not been characterized. Various cultured
TEC lines were examined for expression of the recently described costimulatory molecule
B7RP-1 (B7h), a ligand of the T cell molecule inducible costimulator (ICOS), and expression
was compared with that of B7. 1, B7. 2, and CD40. B7RP-1 and CD40 were abundantly …