The C-type lectin SIGN-R1 mediates uptake of the capsular polysaccharide ofStreptococcus pneumoniaein the marginal zone of mouse spleen

• DOI: 10.1073/pnas.0307124101
• Publication Date: 2004-01-06T18:12:57Z
• Authors: Young-Sun Kang; Jae Y. Kim; Sandra A. Bruening; Maggi Pack; Anna Charalambous; Alla Pritsker; Thomas M. Moran; Jutta M. Loeffler; Ralph M. Steinman; Chae Gyu Park
• Keywords: Avidity

SIGN-R1, a recently discovered C-type lectin expressed at high levels on macrophages within the marginal zone of spleen, mediates uptake dextran polysaccharides by these phagocytes. We now find that encapsulated Streptococcus pneumoniae are rapidly cleared from bloodstream, and capture also takes place when different cell lines express SIGN-R1 after transfection. To assess role capsular polysaccharide S. (CPS) in interaction with pneumococci, we first studied binding serotype 14 CPS transfected cells. Binding was observed much higher avidity (3,000-fold) for than dextran. The CPSs four serotypes were vivo . establish this uptake, selectively down-regulated expression pretreatment mice antibodies, including newly generated hamster monoclonal called 22D1. For several days transient knockout, unable to take up either or dextrans. Therefore, have receptor interacts pneumococcal polysaccharides, setting stage further studies functional consequences interaction.