Sandwich immunoassay for the detection of lipoteichoic acid

Abstract

A sandwich immunoassay has been developed for the detection of lipoteichoic acid (LTA), a major cell wall constituent of gram-positive bacteria, from whole blood and ISOLATOR supernate. Monoclonal antibodies were produced to purified LTA from Streptococcus mutans, BHT and were further characterized for crossreactivity with gram-positive and negative bacteria and for reactivity to substituted and unsubstituted LTA. Eight monoclonal antibodies were identified that reacted exclusively with gram-positive bacteria. Those antibodies able to capture 3H-LTA were chosen to develop a sandwich immunoassay. The assay has a sensitivity of 0.2 ng LTA/mL in PBS, 0.5 ng/mL in whole blood and 2.0 ng/mL in whole blood that has been processed through the ISOLATOR. Further development of this assay may lead to the rapid detection of LTA from body fluids.