Arthritis in rats can be transferred to naïve recipients with Ex Vivo activated arthritogenic CD4+ T cells. In this model, autoreactive cells are transferred to naïve recipient rats following activation in presence of the test item ex vivo. We know from earlier studies that it is CD4+ T cells that transfer the disease and this model provides an opportunity to study the effect of novel drug candidates ex vivo in a controlled manner requiring low amount of test item. Splenocytes are collected from donor rats day 10-14 after induction of Pristane Induced Arthritis (PIA). Cells are stimulated ex vivo for 48 hours with Concanavalin A. After 48 hours of T cell activation in the presence of drug candidate, the cells can be transferred to naïve recipient rats that develop arthritis with onset estimated to 5-8 days after transfer. Cells can be analysed for used as a tool to study the direct or indirect effect of novel candidate drugs on the immune cells in an Ex Vivo assay providing a controlled environment where concentration of compounds and cellular phenotypes can be closely examined, i.e. without concern of formulation, bioavailability and first pass metabolism.