University of Pretoria

Carl Baumeister

Jan Adrianus Verschoor

Walter Allen Shaw

Immobilising isolated mycolic acid antigens of tuberculous mycobacterial origin or a synthetic analogue thereof on a screen-printed electrode by binding of the antigens to a self-assembled monolayer comprising a thiolated hydrophobic substance to produce immobilized mycolic acids antigens in the form of a mycolic acid antigen-containing self-assembled monolayer coating on a surface of the electrode.

Method of diagnosing tuberculosis

Mycolic acid antigen containing liposomes, and an electrode immobilised antigens of tuberculous mycobacterial origin are produced. A diagnostic sample from a human suspected of having tuberculosis is diluted and divided into first and second samples. A control sample comprising the first sample and a redox probe is exposed to the liposomes. A test sample comprising the second sample and a redox probe is exposed to liposomes not containing mycolic acid antigens. The control sample is contacted with the immobilised antigens to allow antibodies therein to bind to the antigens. The test sample is contacted with the immobilised antigens to allow any antibodies therein to bind to the antigens. The degree of binding in the samples is compared by electrochemical impedance spectroscopy. Any observed lesser binding by the control sample is an indicator of antibodies to the antigens in the diagnostic sample, indicating tuberculosis in the human.

A liposomal composition comprising a sterol-modified lipid and a purified mycobacterial lipid cell wall component or analog or derivative thereof is described. The composition is useful as a lipid antigen-presenting vehicle for the detection of lipid antigen specific biomarker antibodies in antibody containing biological samples in the diagnosis of active tuberculosis. The purified lipid cell wall component is typically a purified mycolic acid or a mixture of mycolic acids from athat produces mycolic acids. The sterol-modified lipid is typically a phospholipid.

Liposomal composition comprising a sterol-modified lipid and a purified mycobacterial lipid cell wall component and its use in the diagnosis of tuberculosis

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Lynnwood Manor, South Africa

Carl Baumeister