Figure 5. Removal of the C-terminal acidic tail abrogates the inhibitory effect of HMGB1 on phagocytosis in vivo.

Apoptotic neutrophils (10⁷) with HMGB1, ΔC-HMGB1, or mouse albumin (2 μg) were administered intratracheally in 50 μl PBS into anesthesized mice. BAL was performed with 1 ml cold PBS containing 5 mM EDTA 90 min later. Cytospin slides were prepared using 200 μl BALF, and phagocytosis of apoptotic neutrophils by alveolar macrophages was assessed. The phagocytosis index is represented as the percentage of alveolar macrophages containing at least 1 ingested neutrophil; n = 3 mice in each group; ***P < 0.001. A second independent experiment provided similar results.