SP-D binds to purified lipopolysaccharide (LPS) isolated from a variety of Gram-negative organisms [35, 41] . In addition, LPS is the major cell wall component that is labeled on lectin blotting of outer membranes isolated from Escherichia coli [41] . The latter interactions involve the recognition of the core oligosaccharide domain, which contains glucose and heptose [41] . SP-D interacts preferentially with purified LPS molecules characterized by short or absent O-antigens and preferentially agglutinates bacterial strains expressing a predominance of rough (O-antigen-deficient) LPS [41, 44] .