LIPOPOLYSACCHARIDE-BINDING PROTEINS AND THEIR INVOLVEMENT IN THE BACTERIAL CLEARANCE FROM THE HEMOLYMPH OF THE SILKWORM BOMBYX-MORI

Proteins having the ability to bind to Escherichia coil K12W3110 (roug h (R) mutant) were isolated and purified by affinity precipitation fro m the larval hemolymph of the silkworm Bombyx mori. These proteins wer e found to consist of two components with molecular masses of 43 kDa a nd 40 kDa by SDS/PAGE. They bound to all E. coli R mutants (Ra, Rb,, R e, Rd, and Re) and Salmonella minnesota R mutants. However, they did n ot bind to smooth types of the above bacteria. They bound to both lipo polysaccharide(LPS)-coated and lipid-A-coated microtiter plates and ha ve similar dissociation constants for LPS and lipid A. This indicates that the binding proteins recognize the lipid A portion of LPS and thu s, we have named these proteins BmLBP (B. mori LPS-binding proteins). We also found that BmLBP participated in the clearance of E. coli cell s injected into the body cavity of the silkworm.