Identity of limulus amoebocyte lysate-active root surf ace materials from periodontally involved teeth

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Abstract
A new approach has been developed to circumvent the problems of false positive reactions in the Limulus Amoebocyte Lysate (LAL) assay for lipopolysaccharide (LPS) in root surface materials. These LAL-reactive materials include thrombin, thromboplastin, ribonuclease, ribonucleic acid, lipoteichoic acid and peptidoglycan fragments. In the present study, hot phenol/water extraction of these substances followed by ultracentrifugation of the resulting aqueous phases reduced their concentrations to very low levels. Furthermore, the application of Polymyxin B/Sepharose 4B affinity chromatography to these extracts enabled their intrinsic LAL-activity to be determined. Use of these techniques to assay root surface materials has identifed LPS as being the major LAL-reactive material present. The mean LPS yield for the periodontally involved teeth was 4.13 .mu.g/tooth, representing 2.82 .mu.g/root. In contrast, the mean yield of LPS for the periodontally uninvolved teeth was 3.12 ng/tooth.