Abstract: Objective To obtain the lipopolysaccharide of Mycobacterium tuberculosis to detect TB refference sera,and to evaluate its potential value for serodiagnosis of tuberculosis. Methods Lyse Mycobacterium tuberculosis in ice by sonication,and then treat with phenol/chloroform,chloroform/methanol,DNase I and RNase.Remove proteins,lipide and nucleotides from the cellular glycans and lipopolysaccharide(LPS-1) by a step of dialysis.LPS-1 was separated into a aqueous phase(LPS-2) containing arabinomannan(AM) and an amphipathic detergent-rich phase(LPS-3)containing lipoarabinomannan(LAM) and lipomannan(LM) by Triton-X114 phase separation technique.These LPSs were used as antigens to detect TB postive and negative refference sera by indirect ELISA method. Results The sensitivity and the specificity of LPS-1 used as antigen were 71.7% and 96%,those of LPS-3 used as antigen were 43.9% and 100%,respectively. Conclusions Using LPS as antigen to detect anti-TB antibodies in sera had satisfactory the specificity.LPS might be selected as one of serodiagnostic antigens of tuberculosis.

Key words: Mycobacterium tuberculosis, Lipopolysaccharide, Antigen