Isolation, partial characterization, and concentration in experimental sepsis of baboon lipopolysaccharide-binding protein

Lipopolysaccharide-binding protein (LBP) is important for mediating host re sponses to lipopolysaccharide (LPS). The structure and properties of human, rabbit, and murine LBP have been previously described. In this study we pa rtially characterized baboon LBP and investigated its appearance in experim ental sepsis, Recurrent bacteremia was induced in baboons by infusion of li ve Escherichia coli organisms over a 2-hour period at 0, 24, and 48 hours, To assay baboon plasma LBP levels, an enzyme-linked immunosorbent assay wit h cross-reactive antibodies to human LBP was developed. Control baboon plas ma LBP concentrations were 2 to 5 mug/mL. During experimental sepsis, baboo n plasma LBP levels increased to between 200 and 350 mug/mL and in parallel with the increase in C-reactive protein levels, Baboon LBP was isolated fr om acute phase serum by ion-exchange chromatography followed by immune-affi nity chromatography. Its NH2-terminal sequence (XNPGLVARTTNKGLEYSAQE) and i ts molecular weight (similar to 60 kd) were determined and were proved to b e highly homologous to human LBP.