Fig. 2

SNC Id1 expression is significantly higher in inflamed ST and in the ankles of K/BxN serum-induced mice. a Id1 expression was visualized on SNCs in ST by IHC. A significantly greater percentage of SNCs were positive for Id1 in RA compared to OA and NL ST. b Percentages of cells expressing Id1 were also evaluated on SNCs from joint tissues taken from K/BxN serum-induced mice. A significantly greater percentage of SNCs positive for Id1 compared to Wt (noninduced mice) was found. c Murine tissues were blocked and then incubated using a rabbit anti-mouse Id1 antibody (CalBioreagents). After washing, tissues were incubated with a biotinylated anti-rabbit secondary antibody (Vector Laboratories). Tissues were washed and subsequently developed with the Vectastain ABC kit (Vector Laboratories). Id1 is found on SNCs near the bone in the K/BxN mouse ankles. Id1 inhibitor of DNA binding 1, IgG immunoglobulin, NL normal, OA osteoarthritis, RA rheumatoid arthritis, SNC synovial cell, ST synovial tissue, Wt wildtype