Lipids and sugars in Mycobacterium host-pathogen interaction

Pathogenic Mycobacteria are predominantly intracellular parasites capable of replicating within the normally hostile environment of macrophages even in the face of a highly orchestrated host immune response. An important key to the success of pathogenic mycobacteria is their unusual cell wall structure. Also secreted bacterial proteins are reportedly involved in ‘paralyzing’ the mechanism in phagocytic cells that acidify the lysosome, thus ensuring the survival of the bacteria in an immature phagosome. Nevertheless, most of the data sofar are indirect and remain to be confirmed through the generation and study of mutants in the relevant pathways in slow-growing Mycobacteria. To this end, we have generated a large PCR-screenable, ordered M. bovis BCG transposon insertion mutant library. Results obtained with mutants in the ManLAM biosynthesis pathway will be reported, which counter-argue a necessity for this component in phagosomal maturation inhibition, contrary to previously held beliefs in the field.