Novel generation mycobacterial adjuvant based on liposome-encapsulated monomycoloyl glycerol from Mycobacterium bovis bacillus Calmette-Guérin.

The immunostimulatory activity of lipids associated with the mycobacterial cell wall has been recognized for several decades and exploited in a large variety of different adjuvant preparations. Previously, we have shown that a mycobacterial lipid extract from Mycobacterium bovis bacillus Calmette-Guérin delivered in cationic liposomes was a particular efficient Th1-inducing adjuvant formulation effective against tuberculosis. Herein, we have dissected the adjuvant activity of the bacillus Calmette-Guérin lipid extract showing that the majority of the activity was attributable to the apolar lipids and more specifically to a single lipid, monomycoloyl glycerol (MMG), previously also shown to stimulate human dendritic cells.

beta1-Integrins determine the dendritic morphology which enhances DC-SIGN-mediated particle capture by dendritic cells.

The morphology of antigen-presenting dendritic cells (DCs) is characterized by the presence of numerous long dendrites. The formation of these processes is shown to require the interaction between the beta1-integrin (CD29) on the surface of the DCs and fibronectin in the extracellular matrix. This interaction occurs at focal contacts formed at the tips of dendrites, which contain high concentrations of the beta1-integrins, actin and the cytoskeletal proteins vinculin, paxillin and talin.