Endotoxin, also known as lipopolysaccharides (LPS), is the major mediator
of septic shock due to Gram-negative bacterial infection. Chemically
synthesized S3 peptide, derived from Sushi3 domain of Factor C, which is
the endotoxin-sensitive serine protease of the limulus coagulation
cascade, binds and neutralizes LPS activity. Fluorescent tagged-S3 is
shown to detect LPS-containing bacteria. For large-scale production of S3
and to mimic other pathogen-recognizing molecules, tandem multimers of
the S3 gene were constructed and expressed in E. coli. Tetramer of S3 for
example is shown to display an enhanced inhibitory effect on LPS-induced
activities. An affinity matrix based on tetramer of S3 is also shown to
be particularly efficient at removing LPS.