Bacterial pseudaminic acid binding to Siglec-10 induces a macrophage interleukin-10 response and suppresses phagocytosis.

Pseudaminic acid (Pse) on pathogenic bacteria exopolysaccharide engages with the sialic acid-binding immunoglobulin-type lectin (Siglec)-10 receptor on macrophages the critical 7--acetyl group. This binding stimulates macrophages to secrete interleukin 10 that suppresses phagocytosis against bacteria, but can be reverted by blocking Pse-Siglec-10 interaction with Pse-binding protein as a promising therapy.