Peptidoglycan–polysaccharide (PG-PS)-induced polyarthritis is attenuated in CD14 knockout animals: morphological assessment. (a) Ankle joints at day 3 after intravenous injection of PG-PS. The upper row shows the joint of a wild-type mouse and the lower row the joint of a CD14 knockout mouse. Synovium (S), tibia (T), tarsal (Ta), joint space (J), cartilage (C), and fibrinous exudates (F) are indicated. Hematoxylin–eosin counterstaining was employed and the original magnifications are as follows: left column 12.5× and right column 40×. Representative data from 10 joints in each group are shown. (b) Histological score. The severity of arthritis was assessed as described in the Materials and methods section. Data are shown as means ± standard error of the mean (n = 10). The significance of difference between groups was calculated by using the Mann–Whitney rank sum test. *P < 0.05.