The pathogenicity of mycobacteria is directly related to their ability to survIve within macrophages, thereby circumventing host defense responses. This ability to resist degradation in macrophage phagosomes/lysosomes derives in large part from the complex structure of the cell wall of Mycobacterium tuberculosis. Surface exposure of lipid and glycolipid components of the mycobacterial cell wall is considered to be a major factor in the virulence of the pathogen by orchestrating the dialogue with host cells. Their interactions and modulating properties on host macrophage functions may contribute to our understanding of the pathogenesis of tuberculosis. In this study the modulating properties on macrophage functions by the major mycobacterial cell wall lipids, mycolic acids, were investigated. The investigation focused not only on the physical changes induced in macrophages as a result of the interaction with mycolic acids but also on the modulation of macrophage functions involved in innate and adaptive immunity. It was concluded that MA was involved both in mechanisms of pathogenesis of M tuberculosis, as in induction of protective immunity. By opening up some of the secrets of pathogenesis and immunity of tuberculosis, it provided new avenues for research to pursue a timeous and efficient solution to the disease. / Dissertation (MSc (Biochemistry))--University of Pretoria, 2005. / Biochemistry / unrestricted