To investigate the contribution of the three Vav family proteins to antigen-induced arthritis, we compared the joint swelling induced by the intra-articular injection of methylated bovine serum albumin (mBSA) in single Vav1–/–, double Vav2–/–; Vav3–/– and triple Vav1–/–; Vav2–/–; Vav3–/– knockout mice. The gene discussed is VAV3; the disease is Arthritis.