Syndecan-1 ectodomains are shed from the cell surface in various organs and released into the circulation in endotoxemic WT mice. (A) WT mice were injected with or without LPS, and their lungs and livers were isolated at 24 hours after LPS. Tissue sections were immunostained with 281-2 rat anti–mouse syndecan-1 ectodomain and Alexa 594 donkey anti–rat IgG antibodies (original magnification, ×200). (B) WT and Sdc1^−/− mice were injected with LPS, and serum levels of syndecan-1 and -4 ectodomains were determined at 0, 1, 8, 24, and 48 hours after LPS by dot immunoblotting (n = 5 at each time point). Error bars indicate SE.