Suppression of arthritis in TLR7-deficient mice. TLR7-/- (n = 12) and control C57Bl/6 (n = 14) mice were immunized with chicken collagen in complete Freund's adjuvant. Arthritis was assessed by (a) clinical score and (b) paw swelling on a daily basis from the first day of disease onset. Data are pooled from three independent experiments. (c) The number of paws affected and the disease incidence were recorded for each group from three separate experiments. (d) The first affected joint was collected after 10 days of disease onset and was fixed and stained with hematoxylin and eosin. (e) Arthritis was scored histologically for TLR7-/- (n = 9) and control C57Bl/6 (n = 10) mice as described in Materials and methods and pooled from two independent experiments. *P < 0.05, **P < 0.01. TLR, Toll-like receptor; WT, wild-type.