Figure 5

Dectin-1 inhibition in vitro and in vivo. (a) In a phagocytosis assay, 2.5 × 10⁶ particles of zymosan were incubated with 10 × 10⁵ RAW 264.7 cells. Laminarin was administered either before (pre adm.) or at the same time as (co adm.) the zymosan particles. Incubation of zymosan particles was performed for 4 hours at 37°C. Laminarin decreased the amount of zymosan bound to and phagocytosed by RAW 264.7 cells by 50% in comparison with a control to which no laminarin had been added (P < 0.05). (b) Laminarin (500 μg) and zymosan (180 μg) in a final volume of 15 μl were co-injected into the right knee joint of C57bl/6 mice (n = 6). Phosphate-buffered saline (15 μl) was injected into the contralateral knee. ^99mTc uptake was measured up to day 7. Comparison of ^99mTc uptake with control mice (n = 8), which received zymosan alone in the right knee, showed an attenuation of inflammation at 4 and 24 hours in the laminarin-treated mice, but did not reach statistical significance. After 72 hours the values were similar.